Impact of cosmic rays and solar energetic particles on the ... · Impact of cosmic rays and solar...

Impact of cosmic rays and solar energetic particles on the

Earthrsquos ionosphere and atmosphere

Peter IY Velinov1 Simeon Asenovski1 Karel Kudela2 Jan Lastovicka3 Lachezar Mateev1 Alexander Mishev45

and Peter Tonev1

1 Institute for Space Research amp Technology Academy of Sciences 1113 Sofia BulgariaCorresponding author e-mail lnmateevbasbg

2 Institute of Experimental Physics SAS Watsonova 47 04001 Kosice Slovakia3 Institute of Atmospheric Physics ASCR Bocni II 14131 Prague Czech Republic4 Institute for Nuclear Research and Nuclear Energy Academy of Sciences 1784 Sofia Bulgaria5 Sodankyla Geophysical Observatory University of Oulu unit Finland

Received 5 June 2012 Accepted 4 March 2013

ABSTRACT

A brief review of the study during COST Action ES0803 of effects due to cosmic rays (CR) and solar energetic particles (SEP) inthe ionosphere and atmosphere is presented Models CORIMIA (COsmic Ray Ionization Model for Ionosphere and Atmosphere)and application of CORSIKA (COsmic Ray SImulations for KAscade) code are considered They are capable to compute the cos-mic ray ionization profiles at a given location time solar and geomagnetic activity Intercomparison of the models as well as com-parison with direct measurements of the atmospheric ionization validates their applicability for the entire atmosphere and for thedifferent levels of the solar activity The effects of CR and SEP can be very strong locally in the polar cap regions affecting thephysical-chemical and electrical properties of the ionosphere and atmosphere Contributions here were also made by the anomalousCR whose ionization is significant at high geomagnetic latitudes (above 65ndash70) Several recent achievements and application ofCR ionization models are briefly presented This work is the output from the SG 11 of the COST ES0803 action (2008ndash2012) andthe emphasis is given on the progress achieved by European scientists involved in this collaboration

Key words cosmic rays ndash solar energetic particles ndash ionization ndash ionosphere ndash atmosphere ndash solar activity ndash solar-terrestrialrelationships

1 Introduction

The investigation of ionization processes in the ionosphere andatmosphere is important for better understanding of spaceweather mechanisms The galactic cosmic rays (CR) influencethe ionization and therefore the electrical parameters in theplanetary atmospheres (Singh et al 2011) They change alsochemical processes ndash for example ozone creation and depletionin the Earthrsquos stratosphere (Brasseur amp Solomon 2005) In thisway CR transfer the impact of solar activity into the atmosphere(Singh et al 2010)

The lower part (50ndash80 km) of the ionospheric D-region isformed by the galactic CR which create there an independentCR layer (Velinov 1968 Nestorov 1969 Velinov et al 1974)However the cosmic rays ionize the whole atmosphere up to100 km Above this altitude the contribution of the electromag-netic X and UV radiations dominates In such a way cosmicrays influence the ionization chemical and electrical state inthe region 5ndash100 km Near ground (0ndash5 km) there is an addi-tional ionization source via natural radioactivity of the soil thatmay be important in some regions related to radon gas emission(Usoskin et al 2011)

Three main components are important for the particle ioni-zation (1) high-energy galactic CR (GCR with energies ~109ndash1021 eV) that are always present in the Earth environment and

are subject to 11-year solar modulation (Kudela 2009) (2)anomalous CR (ACR with lower energies ~106ndash108 eV) at highgeomagnetic latitudes above 65ndash70 and (3) sporadic solarenergetic particles (SEP) of energy ~106ndash1010 eV) Over theyears solar energetic particles have been referred by a numberof descriptive names such as solar cosmic rays solar protonevents and others (Miroshnichenko 2001 2008 Dorman2004 Mertens et al 2012) The effect of the three components(GCR ACR and SEP) is quantitatively studied in the presentpaper

This year 2012 marks the centenary anniversary of the dis-covery of cosmic rays by Victor Hess (Nobel Prize in Physics in1936) Since then the scientific community is interested in theionization effects of space radiation on the atmosphere andEarthrsquos environment The V2 rocket measurements in the mid-dle of the 20th century by James Van Allen (1952) led to thefirst empirical profiles of the ionization effects until 100 km(Velinov et al 1974) After that the first quantitative modelsaiming to calculate the atmospheric ionization were developed(eg Velinov 1966 1968 OrsquoBrien 1971 Dorman ampKrupitskaya 1975) These models used a simplified approachbased on an analytical approximation of the cosmic ray ioniza-tion losses Therefore this approach was not so precise andaccurate Further improvement of these investigations was

J Space Weather Space Clim 3 (2013) A14DOI 101051swsc2013036 P Velinov et al Published by EDP Sciences 2013

OPEN ACCESSRESEARCH ARTICLE

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (httpcreativecommonsorglicensesby20)which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

made by Velinov (1970 1974) Dorman amp Kozin (1983)Velinov amp Mateev (1990) etc

However at altitudes below 30 km the primary cosmic raysinitiate a nucleonic-electromagnetic cascade in the atmospherewith the main energy losses resulting in ionization dissociationand excitation of molecules (see eg Dorman 2004) A princi-pally new approach is the full Monte-Carlo CORSIKA (COs-mic Ray SImulations for KAscade) simulation tool used formodelling the atmospheric nucleonic-electromagnetic cascade(Heck et al 1998)

In the framework of the previous COST-724 action (2003ndash2007) three numerical CR ionization models have been devel-oped (Usoskin et al 2008 2009)

1 The Sofia model includes an analytical approximation ofthe direct ionization by CR primaries above 30 km(Velinov et al 2004 2005a 2005b 2006 2008Buchvarova amp Velinov 2005) as well as the CORSIKAMonte-Carlo package extended by FLUKA package tosimulate the low-energy nuclear interactions below30 km (Velinov amp Mishev 2007 2008a 2008b Mishevamp Velinov 2007 2008)

2 The Oulu CRAC (Cosmic Ray Atmospheric Cascade)model is based on the CORSIKAFLUKA Monte-Carlosimulations and explicitly accounting for direct ionizationby primary CR particles (Usoskin et al 2004 2005Usoskin amp Kovaltsov 2006 Usoskin et al 2008 2009)

3 The Bern model (ATMOCOSMICSPLANETOCOS-MICS code) is based on the GEANT-4 Monte-Carlo sim-ulation package (Agostinelli et al 2003) The mainresults are obtained by Desorgher et al (2005) Schereret al (2007) Usoskin et al (2008 2009) etc

Both codes (CORSIKA and GEANT-4) permit realisticstudy of the cascade evolution in the atmosphere simulatingthe interactions and decays of various nuclei hadrons muonselectrons and photons The result of the simulations is detailedinformation about the type energy momenta location and arri-val time of the produced secondary particles at given selectedaltitude above sea level (asl) (Usoskin et al 2008 2009)

Here we present some developments of these models (inparticular the Sofia model) during the COST ES0803 action(2008ndash2012) their validation and comparison with direct obser-vations and other results We also discuss effects caused bysolar and galactic particles in the atmosphere

2 Model CORIMIA for CR ionization above 30 km

In contrast to the lower atmosphere the ionization of the middleand upper atmosphere where the cascade is not developedallows a relatively simple analytical solution This is relatedto the fact that the atmospheric depth at the altitude of 30 kmis about 10 gcm2 (at 50 km is 1 gcm2) which is much lessthan the nuclear free path of protons and a particles (70and 30 gcm2 respectively) Therefore one can neglect nuclearinteractions in the middle atmosphere above 30 km (upperstratosphere and ionosphere) and consider only ionizationlosses of the primary CR particles (Velinov et al 1974 Usoskinet al 2009) Moreover for the altitude above 50 km one can

further neglect changes of the energy of energetic particles thusreducing the computation of CR ionization to an analytical thintarget model (Velinov 1966 1967a 1968)

In the altitude range from 25ndash30 to 50 km an intermediatetarget model needs to be used that accounts also for the parti-clersquos deceleration due to ionization losses (eg Velinov 1967bVelinov amp Mateev 1990) This model was applied for calcula-tion of electron density and atmospheric electrical conductivi-ties in the middle atmosphere for different particles GCRACR and SEP The intermediate target ionization model wasfurther developed with account of the Chapman function valuesfor the inclined penetrating particles in the spherical atmosphere(Velinov amp Mateev 2008a 2008b Velinov et al 2008 2009)

The program CORIMIA (COsmic Ray Ionization Modelfor Ionosphere and Atmosphere) is developed for calculationof the electron and ion production rate profiles due to cosmicrays using ionization losses (Bohr-Bethe-Bloch function)approximation in six characteristic energy intervals includingthe charge decrease interval for electron capturing (Velinovet al 2011a 2011b 2012)

Here some of results of the detailed model for calculation ofCR ionization rates q ndash the number of electron-ion pairs incm3 per second at given altitude h (km) in the ionosphereand middle atmosphere are presented The mathematicalexpression of the fully operational program CORIMIA is thefollowing (Velinov 1966)

q heth THORN frac14X

i

qi heth THORN

frac14 1

Q

Xi

Z 1

Ei

Z 2p

Afrac140

Z p2thornh

hfrac140Di Eeth THORN dE

dh

i

sin h dh dA dE eth1THORNwhere Di(E) is the CR differential spectrum(cm2 s1 st1 MeV1) (dEdh) are ionization losses(Sternheimer 1961) of particles of type i A is the azimuthangle h is the angle towards the vertical Dh takes intoaccount that at a given height h the particles can penetratefrom the space angle (0 hmax = 90 + Dh) which is greaterthan the upper hemisphere angle (0 90) for flat model Ei

are the energy cut-off which correspond to the geomagneticcut-off rigidity Rc The summation in the ionization integral(1) is made on the groups of nuclei (i = 1 6) protonsp Helium (a particles) Light L (3 Z 5) Medium M(6 Z 9) Heavy H (Z 10) and Very Heavy VH (Z 20) nuclei in the composition of cosmic rays Z is the chargeof the nuclei Q = 35 eV is the energy which is necessary forformation of one electron-ion pair (Porter et al 1976)

21 Model description

Five main characteristic energy intervals and one chargedecrease interval for electron capturing in the approximationof ionization losses (MeV g1 cm2) according to Bohr-Bethe-Bloch formula using experimental data (Sternheimer 1961)are introduced (Velinov et al 2008 2009) The approximationfor CR nuclei (Z gt 1) is the following (Velinov et al 2011b2012)

J Space Weather Space Clim 3 (2013) A14

A14-p2

Here interval 2 of the expression (2) is the charge decreaseinterval for CR nuclei (Z gt 1) For protons (Z = 1) this intervalis not necessary and it falls off E is expressed in MeVnucl Inthis way the accuracy of the obtained results is improved incomparison with the previous three- and four-interval approxi-mations (Velinov amp Mateev 2008a 2008b Velinov et al2011a)

The model can be realized in submodels which evaluate theGCR ACR and SEP contributions with account of the ioniza-tion in the middle atmosphere and lower ionosphere Otherstructures in these submodels are the different characteristicenergy interval contributions in the total ionization This modelcan investigate the impact of random differential spectrumenergy intervals on the ionization in the ionosphere and middleatmosphere For this purpose satellite measurements of differen-tial spectra are used

In this paper we investigate particularly the GCR ionizationfor minimal moderate and maximal solar activity becauseobservations cover this whole range of variability That iscaused by the cosmic ray modulation by the solar wind(Dorman 2004) We perform decomposition for differentgroups of GCR nuclei and for different characteristic energyintervals The properties of the model towards the ionizationlosses function boundaries are realized and studied

22 CR spectra

The differential spectrum of GCR is described by power law

D Eeth THORN frac14 KEc eth3THORNwith the spectral coefficient c 275 for protons and slightlysmaller in magnitude for nuclei (Ginzburg amp Syrovatskii1964 Hillas 1972 Berezinsky et al 1984) Particles withenergy below 20 GeV are subject to solar modulation HereD(E) deviates from the power law (3) and the spectrum hasthe following form (Velinov 1991 Velinov et al 2001)

D Eeth THORN frac14 Keth0939thorn ETHORNc 1thorn aE

b eth4THORN

The constant 0939 is the energy of rest of proton K a and bare parameters of the spectrum which must be determinedThese parameters for protons and for solar minimum have thefollowing values K 185 a 164 and b 078 Theyshow the influence of solar wind modulation into the GCRspectrum It is clear that by relativistic energies of the particlesE raquo 0939 GeV formula (4) becomes (3)

Buchvarova amp Velinov (2010) and Buchvarova et al (2011)propose an empirical model for differential spectra D(E) of

cosmic rays during different phases of solar cycle In this modelparameters are related to the observed CR intensity The empir-ical model proposed here approximates theoretical and experi-mental CR spectra during 11-year solar cycle In the modeldata are used which cover three solar cycles 20 22 and 23

We use the local interstellar spectrum (LIS) from Burgeret al (2000) with modification by Usoskin et al (2005) Exper-imental data for protons and a particles for the ascending part ofsolar cycle 20 (1965ndash1969) are from Hillas (1972) and Simpson(1992) The measurements with LEAP87 (Seo et al 1991)IMAX92 (Menn et al 2000) and CAPRICE94 (Boezio et al1999) are related to solar cycle 22 (1986ndash1996) LEAP87 con-cerns the ascending phase and IMAX92 and CAPRICE94 ndash thedescending phase of solar cycle 22 near solar minimumAMS98 (Alcaraz et al 2000a 2000b) experimental spectrumis near the solar minimum of cycle 23 (1996ndash2008) The mod-elled differential spectra D(E) are compared with BESS mea-surements (Shikaze et al 2007) covering the solar cycle 23(1996ndash2008) These experimental spectra are fitted to the pro-posed empirical model The modulated CR differential spectraare compared with force-field approximation to the one-dimen-sional transport equation and with solutions of two-dimensionalCR transport equation (Buchvarova amp Velinov 2010)

For experimental spectra the calculation of the modelparameters is performed by Levenberg-Marquardt algorithm(Press et al 1991) applied to the special case of least squaresThe proposed model gives practical possibility for constructionof CR spectra on the basis of experimental data from measure-ments From solar minimum to solar maximum the value of aincreases and b remains almost constant (Buchvarova ampVelinov 2010) In general the used by us GCR spectra are prac-tically equal to the spectra of Usoskin et al (2005) and Usoskinamp Kovaltsov (2006)

23 Results for GCR ionization

Model CORIMIA is capable to compute the cosmic ray ioniza-tion profiles at a given location time solar and geomagneticactivity First we will show the calculations in the cusp region(Rc = 0 GV) at different altitudes h (30ndash120 km) In fact theseare the maximum values of ionization in the atmosphere of theEarth The results for ionization rate profiles for the differentgroups of GCR nuclei are presented in Figure 1 The total ion-ization rate (Fig 1B) is composed by the ionization rates frommain groups of the GCR nuclei protons Helium (a particles)Light and Medium (Fig 1A) Heavy and Very Heavy (Fig 1B)

The computational results are obtained with the well-knownWolfram Mathematica computer algebra system version 70(Wolfram Mathematica 2008) The input data are involved in

1

qdEdhfrac14

257 103E05 if kT E 015MeV=n interval 1

1540E023 if 015 E Ea frac14 015Z2 MeV=n interval 2

231 Z2E077 if Ea E 200MeV=n interval 3

68 Z2E053 if 200 E 850MeV=n interval 4

191 Z2 if 850 E 5 103 MeV=n interval 5

066 Z2E0123 if 5 103 E 5 106 MeV=n interval 6

8gtgtgtgtgtgtgtgtgtgtgtltgtgtgtgtgtgtgtgtgtgtgt

eth2THORN

PIY Velinov et al Impact of CR and SEP on the Earthrsquos ionosphere and atmosphere

A14-p3

special input window The output data are displayed in thecorresponding output window They show the inner structureof the model The ionization profiles which are shown inFigures 1A and 1B show the maximal ionization in the Earthrsquosionosphere and atmosphere

The calculations give a decrease of the ionization rates withthe latitude (Fig 2) because of increase of geomagnetic cut-offrigidity from geomagnetic poles (Rc = 0 GV) to the geomag-netic equator (Rc 15 GV) In Figure 2 are presented resultsfor electron production rate q(h) profiles for cusp (geomagneticlatitude k = 90) middle latitudes (k = 41) and equator(k = 0) at minimal moderate and maximal solar activityExperimental data () from rocket measurements (40ndash100 km) are taken from Brasseur amp Solomon (2005) By rea-son of influence of solar wind modulation into the GCR theatmospheric ionization decreases with growth of solar activity

24 Results for ACR ionization

The ionization rates by the different ACR constituents are pro-portional to the magnitude of the corresponding differential

spectrum neutral air density and the ionization rate energyinterval values Figure 3 presents the ionization rate profilesq(h) calculated with CORIMIA from the ACR main constitu-ents Nitrogen (N) Oxygen (O) and Neon (Ne) (Leske et al2011) For comparison GCR ionization q(h) profile at minimalsolar activity (Fig 1) is also given We take recent experimentaldata for the ACR differential spectra from measurements ofAdvanced Composition Explorer (ACE) spacecraft at 1 AUduring the cycle 2324 solar minimum (19 April 2009 to 20November 2009 Leske et al 2011)

The Cosmic Ray Isotope Spectrometer (CRIS) and SolarIsotope Spectrometer (SIS) onboard the ACE have been mea-suring GCR and ACR respectively since the launch of ACEin August 1997 These instruments provide a continuoushigh-precision data set spanning allowing detailed comparisonsof cosmic ray modulation effects throughout more than anentire solar cycle (Leske et al 2011)

For periods near the launch of ACE during the cycle 2223solar minimum in 19971998 and at the cycle 2324 minimumin 2009 the constituents N O and Ne have large ACR compo-nents however C Si and Fe are without significant ACRcontributions

Fig1 Electron production rate q(h) profiles due to GCR in cusp region for A p a L and M groups of nuclei and B H and VH groups of nucleiand the total GCR ionization during minimal solar activity

Fig 2 Electron production rate q(h) profiles due to GCR for cuspmiddle latitudes (k = 41) and equator at minimal moderate andmaximal solar activity Experimental data () are taken fromBrasseur amp Solomon (2005)

Fig 3 Electron production rate q(h) profiles calculated withCORIMIA for ACR main constituents Nitrogen (N) Oxygen (O)and Neon (Ne) (Leske et al 2011) GCR ionization q(h) profile is atminimal solar activity (Fig 1)


A14-p4

Figure 4 presents the resultant ionization profile q(h) fromthe ACR main constituents O + N + Ne shown in Figure 3For comparison GCR ionization q(h) profiles for minimal mod-erate and maximal solar activity for cusp region (Fig 2) are alsogiven From Figure 4 it can be seen that the ACR contributionin the atmospheric ionization dominates over the GCR contri-bution at heights above 65 km at solar maximum and above75 km at solar minimum

The ACR spectrum is different for every ACR occurrenceIn Figure 5 are shown results obtained with CORIMIA fromanother spacecraft data ndash from Voyager measurements in thebeginning of its flight at AU 13 We can use these dataaccording to McDonald et al (2002) From their investigationsit can be seen that the spectrum changes for this case in com-parison with AU = 1 are small

Here are presented electron production rate q(h) profiles forACR main constituents Helium (He) Nitrogen (N) Oxygen(O) and Neon (Ne) (Cummings et al 1984) We have used datafrom the CR subsystem on the Voyager spacecraft during solarminimum conditions near the end of 1977 when there mini-mum modulation of CR fluxes

As Voyager has no data for protons for this period we usedother satellite data compiled by Simpson (1992) during similarconditions The ACR spectra are obtained using the fitting pro-cedure of Mathematica program system (Fit procedure whichgives their analytical expressions) with the experimental datafrom spacecraft measurements (Wolfram Research 2008) Wecompute ACR spectra for H+ He+ N+ O+ and Ne+ with chargeZ = 1 ie singly ionized

The ionization rate is calculated with CORIMIA code as asubroutine in the Mathematica program system (WolframResearch 2008) which generates expressions for the corre-sponding input spectra for CORIMIA code which is startedin it

From Figure 5 is seen that the proton and Helium constitu-ents have significant contributions in the total ACR ionizationFor comparison GCR ionization q(h) profile for minimal solaractivity for cusp region (Fig 1) is also shown The ACR impacton the ionosphere and atmosphere is confined predominantly tothe polar cap regions above geomagnetic latitude approxi-

mately km = 65ndash70 The ACR spectra are effective below100 MeV The GCR spectra have independent contributionabove 100 MeV

25 Results for SEP ionization

Occasionally the Sun emits relativistic energetic particles of suf-ficient energy and intensity to raise radiation levels on Earthrsquossurface to the degree that they are readily detected by neutronmonitors Actually they cause Ground Level Enhancements(GLE) of cosmic rays Since the energies of these solar relativ-istic particles (up to ~109ndash1010 eV) are commensurate with theenergies of galactic cosmic rays sometimes they are calledsolar cosmic rays

The present paper shows the results from CORIMIA pro-gram (Velinov et al 2012) with application to the GLE 69 on20 January 2005 and GLE 05 on 23 February 1956 (Reid1961 Velinov et al 1974) The corresponding differential spec-tra for GLE 69 are taken from the available GOES satellite dataWe investigate the SEP effects in the polar cap region at geo-magnetic latitudes 65ndash80 during two of the most powerfulsolar events which have been observed since 28 February1942 Then was registered GLE 01 and then began the studyof SEP impacts In this way the extreme influence of solaractivity on ionization state of the ionosphere and middle atmo-sphere will be calculated

Unlike the cases of GCR SEP differential spectra varyessentially in time during the course of the investigated eventIt is difficult to make a generalization of global solar influenceon ionization chemistry and electrical conductivities in atmo-sphere for the whole time period That is why it is appropriateto consider more than one moment of SEP impact For the caseof GLE 69 we include two characteristic time points ndash at thebeginning 800 UT and 2300 UT The corresponding differen-tial spectrum in cm2 s1 MeV1 outside of the atmosphere(according GOES data) for the time point at 800 UT is

D Eeth THORN frac14 155 106E232 eth5THORNand for the time point at 2300UT the spectrum is

D Eeth THORN frac14 107E343 eth6THORN

Fig 4 Electron production rate q(h) profiles in the cusp regioncalculated with CORIMIA for resultant (N + O + Ne from Fig 3)ACR ionization and GCR ionization for minimal moderate andmaximal solar activity for cusp region from Figure 2

Fig 5 Electron production rate q(h) profiles calculated withCORIMIA for ACR main constituents protons (p) (Simpson1992) Helium (He) Nitrogen (N) Oxygen (O) and Neon (Ne)(Cummings et al 1984) GCR ionization q(h) profile is at minimalsolar activity for cusp region (Fig 1)


A14-p5

The differential spectrum for GLE 05 (Reid 1961) is

D Eeth THORN frac14 24 1010E5 eth7THORN

The energy E in Eqs (5)ndash(7) is expressed in MeVnucl Thesespectra are obtained in the following way Two data points aretaken from the GOES data lists for protons in Internet for everyspectrum They belong to different energy intervals of measure-ment as given in these data lists After that a system of equa-tions is solved towards both unknown parameters ofspectrum the magnitude and exponent

For the first time CORIMIA program is applied to the GLEand results show that it is suitable for the calculations of the ion-ization effects from solar particles The model embedded in thisprogram includes the full approximation (2) of the Bohr-Bethe-Bloch formula (Velinov et al 2011b 2012 Dorman 2004)using six characteristic energy intervals for CR nuclei groups

We investigate the case of solar proton penetration (chargeZ = 1) in the Earthrsquos atmosphere That means interval 2 is nottaken into account On the other hand we find out that the lastthree high-energy intervals (above 200 MeV) do not have con-tributions to the ionization rate (GLE 69 at 2300 UT and GLE05) (NOAA Space Weather Prediction Center ndash GOES satel-lite) The last two intervals approximately (the energies above2 GeV) for GLE 69 at 800 UT are also without contributionThe dependence of number of particles on the characteristicenergy intervals influences the ionization rate profiles (3)

The SEP submodel for calculation of ionization rates causedby solar particles in the ionosphere and atmosphere withaccount of first three characteristic energy intervals is appliedfor the GLE 69 and GLE 05 events In Figures 6 7 and 8the main results are presented as calculated with CORIMIAprogram Figures 6 and 7 give the ionization rate q(h) profilescaused by SEP during GLE 69 with spectra measured on 20January 2005 at 800 UT and 2300 UT These profiles reflectthe ionization state in the polar oval region for km = 6570 75 80 and the corresponding geomagnetic cut-offs thereThe altitude range includes the height interval 30ndash120 km As itcan be seen in Figures 6 and 7 the profile maxima altitudesgrow with latitude

Figure 8 presents the results of electron production rate cal-culation of the GLE 05 on 23 February 1956 This is the mostpowerful solar proton event which has ever been observed inthe history of space research Similar to other two spectra from20 January 2005 in this case there is an increase of maximumaltitude with increasing latitude

The CORIMIA program is able to calculate the ionizationrates stably and accurately for the effects of any SEP impacton the lower ionosphere and middle atmosphere Its structureis user friendly developed with detailed description of inputand output data in corresponding windows In the future wewill develop and improve the CORIMIA program as directlyapplicable routine for the goals of the space weatherinvestigation

3 Recent Monte-Carlo models for CR ionization

The full Monte-Carlo simulations of CR ionization are relatedto explanation and modeling of different processes in the

Fig 6 Electron production rate q(h) profiles due to SEP eventduring GLE 69 with spectrum measured on 20 January 2005 at 0800UT ER is energy corresponding to geomagnetic cut-off for protons Fig 7 Electron production rate q(h) due to SEP event during GLE

69 with spectrum measured on 20 January 2005 at 2300 UT ER isenergy corresponding to geomagnetic cut-off for protons

Fig 8 Electron production rate q(h) profiles due to SEP eventduring GLE 05 ER is energy corresponding to geomagnetic cut-offfor protons


A14-p6

atmosphere (Bazilevskaya et al 2008) as well as their complexexperimental study (Mishev 2010) At present with the devel-opment of numerical methods and evolution of the knowledgeof high-energy interactions and nuclear processes an essentialprogress in models for cosmic ray ionization processes in theEarth atmosphere is carried out (Desorgher et al 2005 Usoskinamp Kovaltsov 2006 Mishev amp Velinov 2007 Velinov et al2009 2011b) These precise models are based on full Monte-Carlo simulation of the atmospheric cascade The models agreewith 10ndash20 the difference is mainly due to the various had-ron generators and atmospheric models (Usoskin et al 2009)

The Monte-Carlo codes permit to follow the longitudinalcascade evolution in the atmosphere and obtain the energydeposit by different shower components and particles fromground till the upper atmosphere These full target models applythe formalism of ionization yield function Y(h E) (the numberof ion pairs produced at altitude h by one primary cosmic raynucleus with kinetic energy E on the top of the atmosphere)The estimation of atmospheric ion rate production is based onequation (Usoskin et al 2009)

q h kmeth THORN frac14Z 1

E0

D E kmeth THORNY hEeth THORNq heth THORNdE eth8THORN

where D(E) is the differential primary cosmic ray spectrum ata given geomagnetic latitude for a given component of pri-mary cosmic ray Y is the yield function and q(h) is the atmo-spheric density (g cm3)

31 An extension of CRAC ionization model to the upperatmosphere

Ionization of the upper atmosphere is important for the atmo-spheric chemistry and dynamics (Krivolutsky et al 2005Lastovicka amp Krizan 2005) The ionization in the upper atmo-sphere is usually computed using an analytical approximation(Vitt amp Jackman 1996) and is typically focused upon the energyrange of primary cosmic rays below 500 MeV (Wissing ampKallenrode 2009) These models are applicable on sporadicand highly temporary variable ionization effect of solar ener-getic particles and are less suitable to study galactic cosmicrays

In this connection the Oulu model was extended to theupper atmosphere (Usoskin et al 2010) The extension of themodel is based on a well-known full Monte-Carlo simulationof the atmospheric cascade and an additional thin target analyt-ical approach In the model the elastic scattering is neglectedand it is assumed that the particle moves straight but losesits energy due to ionization of the ambient air or to nuclearinelastic processes The full details as well as comparisonsare given by Usoskin et al (2010) A detailed comparison forlevel of 100 g cm2 of the atmosphere due to galactic cosmicray protons computed for solar maximum and minimum is car-ried out It is demonstrated that considering only low-energyprotons (lt500 MeV) the ionization effect is underestimatedby a factor of 2 for the solar minimum and a factor of 5 forthe solar maximum conditions even in the uppermost part ofthe atmosphere The difference is larger for the solar maximumbecause of the harder energy spectrum of galactic cosmic rays

When a simplified analytical model is used instead of a fullsolution the underestimation of the ionization rate at01 g cm2 is 10 at 1 g cm2 is 20ndash25 and at 10 g cm2

ndash by a factor of 2 At the atmospheric depth greater than a fewtens of g cm2 (altitudes below about 20 km) the analytical

model is not correct Another significant result from this studyis related to modeling of ionization effect due to solar energeticparticles As was demonstrated the analytical model consideringonly protons with energy below 500 MeV well correspondswith full model computation at about 40 km altitude Belowthe analytical model progressively underestimates the ionizationeffect

32 Effect of model assumptions on computations of CRionization in atmosphere

As it was recently shown various Monte-Carlo models agreewithin 10ndash20 (Usoskin et al 2009) In this connection theirinvestigation is crucial for further modeling of various pro-cesses The largest uncertainties in numerical simulation ofatmospheric cascades are due to the assumed models for hadroninteractions Therefore the influence of low-energy hadroninteraction models in CORSIKA code on the energy depositionrespectively ionization is very important In the past mostlyGHEISHA (Fesefeldt 1985) routines have been used for simu-lations of atmospheric cascades However it is known thatGEANT-GHEISHA suffers from deficiencies in handling thereaction kinematics properly (Ferrari amp Sala 1996) As exampleGHEISHA and FLUKA (Battistoni et al 2007) predict differentmomentum distributions of secondary p plusmn mesons

The largest differences are observed between the energyspectra amount (up to 15) at El 08 GeV and they areclearly correlated with the differences in the predicted distribu-tions of p-mesons at xlab 015 Another difference of 10is observed at El 10 GeV related to the distribution ofcharged pions in p plusmn 14N collisions at xlab 06 While theelectron densities of simulated cascades show no significantdependence on the low-energy model used its influence onthe hadronic and muonic component is obvious

A comparison between GHEISHA 2002 (Fesefeldt 1985)and FLUKA 2006b (Battistoni et al 2007) was carried out(Mishev amp Velinov 2007) It was demonstrated by Mishev ampVelinov (2010 Fig 2) that the largest differences are observedfor the contribution of hadron and muon component specificallyfor 10 GeVnucleon and 1 TeVnucleon energy of the primaryproton However the difference in total ionization is not so cru-cial and both models are applicable specifically below the Pfot-zer maximum (Fig 9) This is mainly due to the cascadeprocess multiplicity (Figs 9C and 9D) the hard steep spectrumof GCR and the dominant contribution of various secondarycomponents as a function of altitude and rigidity cut-off(Figs 9Andash9D)

Similar comparison is performed for various atmosphericprofiles (Mishev amp Velinov 2008) The comparison is carriedout for summer winter and US standard atmospheric profile(Fig 10) The main reason to compare the cosmic ray inducedionization is the observed seasonal variation of the atmosphericprofiles and the observed differences in altitudes of showermaximum (Keilhauer et al 2004 2006) The obtained ioniza-tion yield functions Y are the same below 200 g cm2 for win-ter summer and US standard atmospheric profiles in the case of1 GeV incoming protons (Fig 10A) In the region of Pfotzermaximum the ionization rate tends to slightly increase for win-ter profile (Figs 10B and 10C) Generally the ionization rate forUS standard atmospheric profile lies between the rates for win-ter and summer profiles The obtained results permit a realisticmodeling of a given event


A14-p7

33 Normalization of ionization yield function

As was recently shown the specific ionization yield functionsare different for various primary nuclei particularly in the upperatmosphere (Mishev amp Velinov 2007 2009 Velinov amp Mishev2007) This is due to specifics of atmospheric cascade develop-ment and direct ionization of the initiated particles For correctestimation the contribution to the ionization of each nucleon ofthe cascade it is necessary to simulate large variety of prima-ries An issue is the normalization of ionization yield functionproposed by Usoskin amp Kovaltsov (2006) The normalizationconsists of presentation of ionization yield function Y as ionpairs per nucleon (Mishev amp Velinov 2010 2011a 2011b2012)

The normalized ionization yield functions are still differentin the upper atmosphere They are the same below 24 kmabove sea level for 1 GeVnucleon primary nuclei (Fig 11A)below about 23 km asl for 10 GeVnucleon primary nuclei(Fig 11B) and 22 km asl for 100 GeVnucleon primary

nuclei (Fig 11C) Therefore in the sense of produced ionizationbelow these levels heavier nuclei can be considered as identicalto the corresponding number of a particles ie an oxygennucleus can be substituted by 4 a-particles an iron nucleuscan be substituted by 14 a-particles respectively (Usoskin ampKovaltsov 2006 Mishev amp Velinov 2011a 2011b) Hencefor quantitative studies especially at low altitudes it is possibleto apply this convention which simplifies considerably the sim-ulation However in the region of the upper atmosphere the dif-ference is essential and the contribution of various nuclei to theatmospheric ionization should be considered individually(Mishev amp Velinov 2011a 2011b)

34 Ionization effect in the atmosphere during GLE

In addition to continuous ionization in the Earthrsquos atmospherecaused by galactic cosmic rays a sporadic ionization occurs dur-ing solar energetic particle events potentially affecting the

0 200 400 600 800 1000101

102

103

104

105

0 200 400 600 800 1000

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

Yie

ld fu

nctio

n Y

[ion

pai

rs s

r cm

2 g-1]

Protons 15 GV cut-off

Protons 15 GV cut-offDC

B

Yie

ld fu

nctio

n Y

[Ion

pai

rs s

r cm

2 g-1]

Atmospheric Depth [g cm-2]



A

Fluka Total ionization EM ionization Muon ionization Hadron ionization

Gheisha Total ionization EM ionization Muon ionization Hadron ionization


Fig 9 Ionization yield function Y for primary proton induced atmospheric cascades with different cut-offs (15 5 9 and 15 GV) simulated withFLUKA and GHEISHA hadron generators


A14-p8

Earthrsquos environment (Miroshnichenko 2008 Vainio et al2009) In general such events are low energy and are not ableto initiate atmospheric cascades Their ionization effect is lim-ited to the upper polar atmosphere Hence the studies of theeffects caused by SEP are usually limited to the upper atmo-

sphere above 30 km However as was recently demonstrated(Mishev et al 2010 Usoskin et al 2011) during GLE whichare characterized by very high energy of solar particles capableto induce the atmospheric cascade the ionization effect isimportant specifically in polar atmosphere

0 200

40x10 4

80x10 4

12x10 5

0 300

20x105

40x105

60x105

0 200 400

00

20x106

40x106

Ioni

zatio

n Yi

eld

func

tion

Y [s

r cm

2 g-1]


1 GeVProtons

10 GeV CB

summer profile winter profile US standard

100 GeV

A

Fig 10 Ionization yield function Y computed for winter summer and US standard atmospheric profile as a function of the energy (1 10 and100 GeV) of primary proton nuclei

10 100 1000103

104

105

106

10 100 1000

106

107

10 100

10 0

10 1

10 2

10 3

10 4

10 5

10 6

10 GeVnucleon

Observation depth [ g cm-2]

B C 100 GeVnucleonA 1 GeVnucleon

YIron

YOxygen

YHelium

Norm

alize

d Io

niza

tion

Yiel

d fu

nctio

n Y

[cm

2 g-1 sr

]

Fig 11 Normalization of ionization yield function Y for various nuclei as a function of the energy of the primary nuclei


A14-p9

Awell-studied GLE 69 event on 20 January 2005 was con-sidered for analysis (Butikofer et al 2008) The spectrum ofsolar protons is expressed in two different moments at 0800UT a high energy part with a slope of 232 and at 2300 UTlow-energy part with a slope of 343 (5 6) It is demonstrated(Mishev et al 2010 2011) that the ionization effect on eventonset at 0800 UT (Fig 12A) is greater than that producedby delayed component at 2300 UT (Fig 12B) Since the eventon 20 January 2005 occurred during the recovery phase of theForbush decrease and in the following days an additional sup-pression of the cosmic ray intensity was observed leading to acomplicated time profile of CR flux the net ionization effect iscalculated as a superposition of ion rate from solar particles andreduced galactic CR

In the case of 40 N latitude the effect at 0800 UT is com-parable to the average of galactic CR (Fig 12A) However theion rates quickly decrease with altitude (below 5 km asl) Theionization effect due to low-energy component of the SEP spec-trum namely at 2300 UT is negligible (Fig 12B) In this casethe ion rates are due mostly to reduced galactic CR (ie theeffect is negative after 2300 UT) The situation is quite differ-ent for latitude 60 N (Mishev et al 2011 Fig 7) The ioniza-tion effect due to SEP at 0800 UT is significant The ion ratesfrom solar particles are larger than ion rates from galactic CRby roughly an order of magnitude The effect is significant at

altitudes above about 12 km asl and decreases in the tropo-sphere The effect at 2300 UT due to a low-energy componentas in a previous case is negligible Therefore the ionizationeffect decreases after 2300 UT for 60 N latitude In the caseof 80 N latitude both components at 0800 UT and at 2300UT cause a significant excess of ionization rates in the atmo-sphere The effect at 0800 UT is due mainly to solar protons(Fig 12C) It is significant at altitudes above 10ndash12 km aslAt 2300 UT the effect of solar particles is significant at alti-tudes above 12 km asl and decreases in the troposphereThe ionization effect in this case is due to a reduced galacticCR (Fig 12D) Taking into account the time evolution of theobtained ion rates the conclusion is the ionization effect is neg-ative for 40 N especially in the troposphere and small for60 N due to the accompanying Forbush decrease during theevent The ionization effect is important only in the sub-polarand polar atmosphere at high altitudes during major groundlevel enhancement of 20 January 2005 (Usoskin et al 2011)

Quite recently it was demonstrated that the contribution oflight nuclei specifically Helium could be important for totalionization even at middle latitudes during GLE 69 (Mishev ampVelinov 2012) The estimated ion rate production due to Heliumnuclei is comparable to the average ion rate due to galactic cos-mic rays (Figs 13A and 13B) at 40 N It is above the ion rateproduction due to galactic CR at 60 N (Figs 13C and 13D)

0

20

40

100 101 102 103

0

20

40

10-6 10-5 10-4 10-3 10-2 10-1 100 101 102

0

5

10

15

20

25

30

35

40

101 102 103 104 105-5

0

5

10

15

20

25

30

35

40

101 102 103 104-5

0

5

10

15

20

25

30

35

40

Q [ion pairs s-1 cm-3]

Altit

ude

[ km

as

l]

Average GCR Reduced GCR SEP SEP+Reduced GCR

Q [ion pairs s-1 cm-3atm-1]

Altit

ude

[ km

as

l]

BA40N

0800 UT 2300 UT

2300 UT0800 UT

80N

DC

Fig 12 Time evolution of ionization effect during GLE 69 on 20 January 2005 as function of latitude


A14-p10

and 80 N (Figs 13E and 13F) In addition the ion rate produc-tion due to Helium nuclei is comparable to hard proton spec-trum ion rate production at 60 N (Fig 13C) and soft solarproton spectrum ion rate production at 80 N (Fig 13E) Theion rate due to oxygen and iron nuclei is negligible especiallyin a middle and low atmosphere at 60 N (Figs 13C and 13D)The medium and heavy nuclei contribute to atmospheric ioniza-tion only in the upper atmosphere at 80 N (Figs 13E and 13F)In this respect the SEP event abundant on light and heavy ionsdeserves a special interest and further studies (Mishev et al2012)

4 Applications of ionization models for estimation

of CR influence on atmosphere

Considerations of the role of CR and their variations in generallead to observations in last decades of different types of correl-ative relations between GCR and atmospheric processesresponsible for climate formation An important fact is the pres-ence of correlation between the GCR flux and the global cloudcoverage which controls the albedo (Svensmark 1998) the cov-erage is larger by higher GCR flux ie during low solar activ-ity The existence of this correlation may thus express a link

between solar activity and climate However the relationbetween cloudness and GCR is still a matter of debate andsome recent results particularly those related to the last deepand long solar minimum make this relation questionable(eg Agee et al 2012)

41 CR influence on minor atmospheric constituents

The influence of GCR ACR and SEP should not be neglectedin investigations of the tropospheric and stratospheric chemistryand dynamics The CR ionization models show that the effectsof these particles on the atmosphere are statistically significantin large geographic regions and for a number of relevant atmo-spheric species

In a recent study (Calisto et al 2011) based on applicationof 3-D Chemistry Climate Model SOCOL v20 (Egorova et al2005) and CRAC ionization model (Usoskin amp Kovaltsov2006) statistically significant effects of GCR on troposphericand stratospheric ozone O3 NOx HOx (on annual time scale)were found It was estimated (Vitt amp Jackman 1996) thatGCR produce 30ndash37 middot 1033 molecules of odd nitrogen peryear in the global stratosphere which amounts to about 10of the NOx production following N2O oxidation In addition

Fig 13 Electron production rate q(h) profiles on 20 January 2005 due to SEP and galactic CR for various latitudes as a function of altitude andtime


A14-p11

the northern subpolar stratosphere is supplied with NOx inequal amounts by GCR (71ndash96 middot 1032 molecules yr1) andby N2O oxidation (94ndash107 middot 1032 molecules yr1)

Comparing annual mean response of the zonal mean(Calisto et al 2011) demonstrates that the GCR-induced NOxincrease to exceed 10 in the tropopause region (20 in apolar region) whereas HOx decreases of about 3 caused byenhanced conversion into HNO3 As a consequence ozone isincreasing by up to 3 in the relatively unpolluted southern tro-posphere where its production is sensitive to additional NOxfrom GCRs Conversely in the northern polar lower strato-sphere GCR are found to decrease O3 by up to 3 causedby the additional heterogeneous chlorine activation viaClONO2 + HCl

The modelling of the ionization state of the atmospherehelps to study different aspects of the CR influence on the Earthatmosphere and respectively Earthrsquos climate The statisticallydetermined relations between GCR and climate (on the one site)and lower stratospheric ozone (on the other) hint on the role ofO3 as a mediator of GCR influence on climate Kilifarska(2012a 2012b) This idea has been evolved further in twodirections (i) detailed inventory of the lower stratosphericion-molecular chemistry in order to determine the energeticallyeffective reactions (ii) suggestion of a new mechanism translat-ing the ozone influence down to the surface Kilifarska (2013)suggests that the long-term variations of CR intensity and CRionization appear to be a real driver of O3 variability in thelower stratosphere

Another cosmic ray effect influencing on ozone are the For-bush decreases of GCR The Forbush decreases are causing thegeomagnetic storms which are a primary phenomenon amongspace weather phenomena Strong geomagnetic storms are asa rule associated with Forbush decreases of galactic CR Theyproduce large disturbances in the ionosphere but they affectalso the neutral atmosphere including the total ozone in themiddle atmosphere and troposphere (Lastovicka amp Krizan2005 2009)

Sufficiently strong statistically significant effects of geo-magnetic storms appear to occur in the total ozone at the north-ern higher middle latitudes only for strong events (Ap gt 60) inwinter and under the high solar activity and the east phase ofthe QBO (hereafter E-max) conditions They occur aroundthe 50 N latitudinal circle but not around 40 N and 60 NThe effect is very regional it is strongest and statistically signif-icant at the 3-r level only in the North Atlantic-European sec-tor where it occurs as a substantial increase of total ozone by40ndash50 DU and more not in other longitudinal sectors Thenumber of events under E-max conditions is small but theobserved effect repeats in all events without exception Thetotal ozone is enhanced for about 4ndash5 days It should be men-tioned that small changes of total ozone of the order of 5ndash10 DU are not reliably detectable with respect to noisy back-ground (Lastovicka amp Krizan 2005 2009) Figure 14 illustratesfor Europe 50 N how with more favourable conditions theeffect of strong Forbush decreasesgeomagnetic storms in totalozone is becoming better pronounced

So the Forbush decreases of galactic cosmic rays seem toplay a very important likely decisive role in the effects of geo-magnetic storms on total ozone Strong geomagnetic stormsoccur very rarely without a corresponding Forbush decreasewe found only one such event under E-max winter conditionsover 25 years but in this case a detectable effect in total ozonewas absent On the other hand a few events were found when

the strong Forbush decrease occurred without a stronger geo-magnetic storm and their effects in total ozone were compara-ble with effects of strong geomagnetic storms accompanied bystrong Forbush decreases (Lastovicka amp Krizan 2005 2009)

42 CR influence on atmospheric electric processes

By searching of physical mechanisms responsible for the solar-terrestrial relationships the global atmospheric electric circuit(AEC) (Bering III et al 1998 Rycroft et al 2000 2007Williams 2009) was first put forward as a candidate for a mech-anism responsible for Sun-weather relationships by Markson ampMuir (1980) This suggestion received strong observationalsupport by Tinsley amp Heelis (1993) and was developed furtherin a series of studies (eg Tinsley 2000 Harrison 2004 Tinsley2012) Climate formation processes have been considered asdepending on the rate of creation of electric charges at cloudtops by the ionosphere-ground (air-earth) current in AEC whichcan be sensitive to CR variations These results demonstrate theneed for studying the response of AEC to the modulations ofCR by solar wind

The influence of CR on AEC is realized mainly through theatmospheric conductivity which is a result of ionization GCRof energies lt1011 eV are the only factor of ionization of theair between 5 km and 35 km and have a contribution to theionization up to 90 km in the daytime and up to 100 km atnight ie GCR are necessary for creation and maintenance ofAEC Their 11-year variations during the solar cycle lead tochanges in stratospheric conductivity so that it is larger duringsolar minimum than during solar maximum respectively Therelative factor of solar cycle change of the stratospheric conduc-tivity is about 3 at equatorial 10 at tropics 20 at middle

Fig 14 Total ozone (Europe ndash near 50 N) deviations from averagelevel over days 3 to 15 for major geomagnetic storms under thehigh solar activity conditions in winter All events under high solaractivity (bottom curve) events under the E-phase of QBO (E-QBOmiddle curve) very strong storms (Ap gt 60) under the E-QBO (topcurve) Vertical lines ndash error bars n ndash number of events


A14-p12

and 50 at high and polar latitudes (according to the results ofVelinov amp Mateev 1990) This leads to a small decrease of theaverage air-earth current at polar latitudes during solar maxi-mums compared to solar minimums At equatorial and low lat-itudes the variation of the air-earth current will be yet smallerLarger atmospheric conductivity changes involving largerrange of altitudes (possibly tropospheric) take place during aForbush decreases of GCR and especially during a SEP events

For the goal of investigations of complex relations betweenthe solar activity cosmic rays and AEC which can be a part ofmechanisms of Sun-climate links a numerical model CO-RIAEC (COsmic Radiation Influence on AEC) is developed(Velinov amp Tonev 2008 Tonev amp Velinov 2011 Tsagouriet al 2013) This model serves to evaluate the electric fieldsand currents superimposed to AEC generated as a result ofthe transpolar ionospheric potential difference

The model CORIAEC is designed to evaluate the combinedinfluence of both the cosmic rays and the solar wind to the elec-tric currents and fields superimposed to AEC due to the trans-polar potential CORIAEC is a 3D physically based simulationmodel which estimates the influence of the solar wind on thesuperimposed electric characteristics These last depend onthe parameters of IMF and solar wind on one hand and onconductivity of the ionosphere (which is sensitive to the SEPand ACR) and mesostratosphere (where GCR has a contribu-tion) To represent the link of the IMF and solar wind to thetranspolar electric potentials and fields in CORIAEC the modelof Weimer (1996) is used which provides real-time evaluationsof these characteristics in the ionosphere above the modeldomain It is estimated by CORIAEC that in the polar meso-sphere the superimposed electric field can have variations ofup to tens of mVm and the air-earth current density at surfacecan vary by few tens of percent (Tonev amp Velinov 2011)

The observations of the air-earth current density in balloonmeasurements by Olson (1983) over Lake Superior in the USA(situated at high geomagnetic latitude) showed 20ndash40changes over a solar cycle These experimentally obtainedchanges are somewhat larger than those estimated by the CO-RIAEC model The difference between the model and theexperimental results may take place possibly due to the over-idealized representation of the conductivity in the model whereclean air conductivity is assumed Actually at polar latitudesthe conductivity in the upper troposphere and lower strato-sphere is dramatically reduced due to the presence of aerosolsin those regions especially after volcanic eruptions (Tinsleyamp Zhou 2006) One can also note that because of the strongreduction of the stratospheric conductivity the contribution ofits variations during a solar cycle due to the GCR flux modula-tion significantly increases since the stratospheric conductivitybecomes important in formation of the ionosphere-groundcolumnar resistance

43 CR influence on technological systems

The investigation of impact of cosmic rays and solar energeticparticles on the Earthrsquos environment is important not only forthe atmospheric processes but also for the technological andeven biological systems Ions accelerated to several tens to hun-dreds of MeVare very important for the radiation hazard effectsduring solar radiation storms with electronic element failures onsatellites communication and biological consequences (Kudelaet al 2000) Before their arrival a network by several stationsoperating in real time can provide useful alerts several minutesto tens of minutes in advance CR and SEP of lower energy

interact with the material of the satellites spacecrafts and air-planes and may cause the failures There is variety of effectswith consequences on the reliability of the electronic elementsThe energy deposition in materials results in permanent damagein silicon semiconductor devices This is another reason tostudy in detail the cosmic ray variability and the correspondingionization effects (Kudela et al 2010)

5 Conclusion

In this paper we present the results from CORIMIA and COR-SICA programs and their application to calculations of theGCR ACR and SEP ionization in ionosphere and atmosphereBecause of the different differential spectra of these types ofparticles three main submodels are created These differentspectra determined different impact on the ionization in theEarthrsquos environment

The ionization rate profile values which are calculated withCORIMIA depend on the altitude neutral density atmosphericcut-offs ionization losses geomagnetic cut-offs and spectra ofthe particles

CORIMIA is able to compute profiles for experimentallymeasured differential spectra The evaluation of the spectraand the basic statement of the model have been discussed byVelinov et al (2011a 2011b 2012) In the case with six char-acteristic energy intervals we reach the accuracy which is inaccordance with experimental data (Brasseur amp Solomon2005 Velinov amp Mateev 2008a 2008b) The model can beapplied for different input spectra in interactive mode and fordifferent planetary atmospheres

The SEP spectra at lower latitudes cause smaller values ofthe ionization rate profiles (Figs 6ndash8 and 13) because of thehigher geomagnetic cut offs The maxima do not occur herebecause the atmospheric cut offs value switching appears atlower altitudes It must be noted that the magnitude of differen-tial spectrum dominates at higher altitudes while at lower alti-tudes the number of particles with smaller exponent dominatesThis is due to the greater atmospheric cut-offs which dominateover geomagnetic cut-offs for low altitudes The powerful eventGLE05 has characteristic maximum for geomagnetic latitudekm = 75

In the region below 30 km the nuclear interactions of cos-mic rays with air molecules must be taken into account It isrealized with the program CORSIKA (Sect 3) Above 30 kmwe use the CORIMIA program because the CORSIKA resultsare not reliable owing to the small statics In the transitionregion (25ndash30 km) the CORSIKA results are in accordancewith those from CORIMIA

The simulations from CORIMIA and CORSICA are usedfor quantitative interpretation of CR impact on the ionizationchemical (ozone and other minor constituents) and electricalstate of the ionosphere and atmosphere

The application of Monte-Carlo methods for investigationof cosmic ray ionization is important because it is possible toconsider explicitly the hadron component and therefore to esti-mate effects in the lower (0ndash10 km) and middle (10ndash100 km)atmosphere As was recently demonstrated their applicationin specific realistic conditions (Mishev amp Velinov 20082010) permits detailed study of the ionization effect especiallyat different altitudes (Mishev et al 2010 Usoskin et al 2011)

In addition to the well-studied significant upper atmosphereionization effect during GLE 69 on 20 January 2005 it is


A14-p13

shown that ionization effect is significant at sub-polar and polaratmosphere (Mishev et al 2011 Usoskin et al 2011) with fasttropospheric decrease Moreover it is demonstrated that theionizaton effect at low altitudes may be negative due to Forbushdecrease of GCR at middle latitudes Therefore the effect ofsporadic solar energetic particle events is limited on a globalscale but most energetic events could be strong locally partic-ularly in sub-polar and polar region affecting the physical-chemical properties of the upper atmosphere Since the largeSEP events leading to GLEs are different in spectra and compo-sition their detailed study is connected with detailed informa-tion about heliospheric and geospace conditions In thisconnection extension of the existing models to the upper atmo-sphere is very important as well as their comparison with ana-lytical models

General agreement exists that cosmic ray ionization due toCR and SEP influences the ozone concentration in the atmo-sphere As mentioned above the ionization effect due to SEPsis important only in a sub-polar and polar atmosphere This isimportant for studies of the variations of minor atmosphericconstituents The 20 January 2005 SEP event caused largeenhancements in the northern polar HOx and NOx constituentsin the mesosphere which lead to ozone decrease of the order of40 However on the basis of the obtained ion rates it is dem-onstrated that the tropospheric and stratospheric ionizationeffects due to SEP are important on short to medium time scalesin polar atmosphere and they are almost negative compared tothe average GCR ionization on medium time scales at middlelatitudes due to the accompanying Forbush decrease Additionalmore detailed studies on the influence on minor components ofthe atmosphere deserve special interest

Thus a new methodology is presented to study the CR ion-ization of the ionosphere and atmosphere in full detail usingrealistic analytical and numerical models calibrated by directobservations

Acknowledgements This article is the output of SG11 lsquolsquoProgress inscientific understanding of space weatherrsquorsquo of the European COSTAction ES0803 lsquolsquoDeveloping space weather products and servicesin Europersquorsquo The authors are grateful to COST Action ES0803 forthe permanent interest and support to our SWSC studies We thankProf Klaus Scherer and an anonymous referee for reviewing this pa-per and their comments and suggestions which helped us to improvethis paper

References

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Agostinelli S J Allison K Amako J Apostolakis H Araujoet al GEANT 4 ndash a simulation toolkit Nucl Instrum MethodsPhys Res A Accelerators Spectrometers Detectors andAssociated Equipment 506 (3) 250ndash303 2003

Alcaraz J B Alpat G Ambrosi H Anderhub L Ao et al Cosmicprotons AMS collaboration Phys Lett B 490 27 2000a

Alcaraz J BAlpatGAmbrosiHAnderhubag LAo et alHelium innear Earth orbit AMS collaboration Phys Lett B 494 193 2000b

Battistoni G S Muraro PR Sala F Cerutti A Ferrari et al MAlbrow and R Raja The FLUKA code description andbenchmarking in Proc of the Hadronic Shower SimulationWorkshop 2006 Fermilab 6ndash8 September 2006 896 AIPConference Proc 31ndash49 2007

Bazilevskaya GA IG Usoskin EO Fluckiger RG Harrison LDesorgher et al Cosmic ray induced ion production in theatmosphere Space Sci Rev 137 149ndash173 2008

Bering III EA AA Few and JR Benbrook The global electriccircuit Phys Today 51 (10) 24 1998

Boezio M P Carlson T Francke N Weber M Suffert et al Thecosmic ray proton and helium spectra between 04 and 200 GVAstrophys J 518 457 1999

Brasseur G and S Solomon Aeronomy of the Middle AtmosphereSpringer Dordrecht 2005

Buchvarova M and PIY Velinov Modeling spectra of cosmic raysinfluencing on the ionospheres of earth and outer planets duringsolar maximum and minimum J Adv Space Res 36 (11) 2127ndash2133 2005

Buchvarova M and PIY Velinov Empirical model of cosmic rayspectrum in energy interval 1 MeVndash100 GeV during 11-year solarcycle J Adv Space Res 45 (8 1) 1026ndash1034 2010

Buchvarova M PIY Velinov and I Buchvarov Model approx-imation of cosmic ray spectrum Planet Space Sci 59 (4) 355ndash363 2011

Burger RA MS Potgieter and B Heber Rigidity dependence ofcosmic ray proton latitudinal gradients measured by the Ulyssesspacecraft implications for the diffusion tensor J Geophys Res105 27447 2000

Butikofer R EO Fluckiger L Desorgher and MR Moser Theextreme solar cosmic ray particle event on 20 January 2005 andits influence on the radiation dose rate at aircraft altitude SciTotal Environ 391 (2ndash3) 177ndash183 2008

Calisto M I Usoskin E Rozanov and T Peter Influence ofgalactic cosmic rays on atmospheric composition and dynamicsAtmos Chem Phys 11 4547ndash4556 2011

Cummings AC EC Stone and WR Webber Evidence that theanomalous cosmic-ray component is singly ionized Astrophys J287 99ndash103 1984

Desorgher L E Fluckiger M Gurtner MR Moser R Butikoferet al Atmocosmics a GEANT4 code for computing theinteraction of cosmic rays with the Earths atmosphere Int JMod Phys A 20 (29) 6802ndash6804 2005

Dorman LI Cosmic Rays in the Earthrsquos Atmosphere andUnderground Kluwer Academic Publishers Dordrecht 2004

Dorman LI and ID Kozin Cosmic Radiation in the UpperAtmosphere Fizmatgiz Moscow 1983

Dorman LI and TM Krupitskaya Calculation of expected ratio ofsolar cosmic ray ion generation speeds on different altitudes inCosmic Rays Nauka Moscow 15 30ndash33 1975

Egorova T E Rozanov V Zubov E Manzini W Schmutz and TPeter Chemistry-climate model SOCOL a validation of thepresent-day climatology Atmos Chem Phys 5 1557ndash1576DOI 105194acp-8-6365-2005 2005

Ferrari A and P Sala ATLAS Int Note PHYS-No-086 CERNGeneva 1996

Fesefeldt HC GHEISHA program Technical Report PITHA 85-02 III Physikalisches Institut RWTH Aachen Physikzentrum5100 Aachen Germany September 1985

Ginzburg VL and SI Syrovatskii The Origin of the Cosmic RaysPergamon Press Oxford 1964

Harrison RG The global atmospheric electrical circuit and climateSur Geophys 25 (5ndash6) 441ndash484 2004

Heck D J Knapp JN Capdevielle G Schatz and T ThouwCORSIKA A Monte Carlo Code to Simulate Extensive AirShowers Forschungszentrum Karlsruhe Report FZKA 60191998

Hillas AM Cosmic Rays Pergamon Press Oxford 1972Keilhauer B J Blumer R Engel HO Klages and M Risse

Impact of varying atmospheric profiles on extensive air showerobservation atmospheric density and primary mass reconstruc-tion Astropart Phys 22 (3ndash4) 249ndash261 2004

Keilhauer B J Blumer R Engel and HO Klages Impact ofvarying atmospheric profiles on extensive air shower observationfluorescence light emission and energy reconstruction AstropartPhys 25 (4) 259ndash268 2006

Kilifarska NA Climate sensitivity to the lower stratospheric ozonevariations J Atmos Sol Terr Phys 9091 9ndash14 2012a


A14-p14

Kilifarska NA Ozone as a mediator of galactic cosmic rayinfluence on climate Sun Geosphys 7 (2) 97ndash102 2012b

Kilifarska NA An autocatalytic cycle for ozone production in thelower stratosphere initiated by Galactic Cosmic rays CR AcadBulg Sci 66 (2) 243ndash252 2013

Krivolutsky A A Kuminov and T Vyushkova Ionization of theatmosphere caused by solar protons and its influence onozonosphere of the Earth during 1994ndash2003 J Atmos Sol TerrPhys 67 105ndash117 2005

Kudela K On energetic particles in space Acta Phys Slovaca 59537ndash652 2009

Kudela K M Storini MY Hofer and A Belov Cosmic rays inrelation to space weather Space Sci Rev 93 (1ndash2) 153ndash1742000

Kudela K H Mavromichalaki A Papaioannou and M Geronti-dou On mid-term periodicities in cosmic rays Sol Phys 266173ndash180 2010

Lastovicka J and P Krizan Geomagnetic storms Forbushdecreases of cosmic rays and total ozone at northern highermiddle latitudes J Atmos Sol Terr Phys 67 119ndash1242005

Lastovicka J and P Krizan Impact of strong geomagnetic stormson total ozone at southern higher middle latitudes Stud GeophysGeod 53 151ndash156 2009

Leske RA AC Cummings RA Mewaldt and EC Stone Anom-alous and galactic cosmic rays at 1 AU during the cycle 2324 solarminimum Space Sci Rev DOI 101007s11214-011-9772-1 2011

Markson R and M Muir Solar wind control of the Earthrsquos electricfield Science 208 979ndash990 1980

McDonald FB B Klecker RE McGuire and DV ReamesRelative recovery of galactic and anomalous cosmic rays at 1 AUfurther evidence for modulation in the heliosheath J GeophysRes 107 (A8) DOI 1010292001JA000206 2002

Menn W M Hof O Reimer M Simon AJ Davis et al Theabsolute flux of protons and helium at the top of the atmosphereusing IMAX Astrophys J 533 281 2000

Mertens CJ BT Kress M Wiltberger WK Tobiska BGrajewski X Xu in Atmospheric Ionizing Radiation fromGalactic and Solar Cosmic Rays Current Topics in IonizingRadiation Research edited by M Dr Nenoi InTech Availablefrom http wwwintechopencombookscurrent-topics-in-ioniz-ing-radiation-researchatmospheric-ionizing-radiationfrom-galac-tic-and-solar-cosmic-rays 2012

Miroshnichenko LI Solar Cosmic Rays ASSL 260 KluwerAcademic Publishers Dordrecht The Netherlands 2001

Miroshnichenko LI Solar cosmic rays in the system of solar-terrestrial relations J Atmos Sol Terr Phys 70 450ndash4662008

Mishev A A study of atmospheric processes based on neutronmonitor data and Cherenkov counter measurements at highmountain altitude J Atmos Sol Terr Phys 72 (16) 1195ndash11992010

Mishev A and PIY Velinov Atmosphere ionization due to cosmicray protons estimated with CORSIKA code simulations CRAcad Bulg Sci 60 (3) 225ndash230 2007

Mishev A and PIY Velinov Effects of atmospheric profilevariations on yield ionization function Y in the atmosphere CRAcad Bulg Sci 61 (5) 639ndash644 2008

Mishev A and PIY Velinov Normalized atmospheric ionizationyield functions Y for different cosmic ray nuclei obtained withrecent CORSIKA code simulations CR Acad Bulg Sci 62 (5)631ndash640 2009

Mishev A and PIY Velinov The effect of model assumptions oncomputations of cosmic ray induced ionization in the atmosphereJ Atmos Sol Terr Phys 72 476ndash481 2010

Mishev A and PIY Velinov Renormalized ionization yieldfunction Y for different nuclei obtained with full Monte Carlosimulations CR Acad Bulg Sci 64 (7) 997ndash1006 2011a

Mishev A and PIY Velinov Normalized ionization yield functionfor various nuclei obtained with full Monte Carlo simulations JAdv Space Res 48 19ndash24 2011b

Mishev A and PIY Velinov Contribution of cosmic ray nuclei ofsolar and galactic origin to atmospheric ionization during SEPevent on 20 January 2005 CR Acad Bulg Sci 65 (3) 373ndash3802012

Mishev A PIY Velinov and L Mateev Atmospheric ionizationdue to solar cosmic rays from 20 January 2005 calculated withMonte Carlo simulations CR Acad Bulg Sci 63 (11) 1635ndash1642 2010

Mishev A PIY Velinov L Mateev and Y Tassev Ionization effectof solar protons in the Earth atmosphere ndash case study of the 20January 2005 SEP event J Adv Space Res 48 1232ndash1237 2011

Mishev A PIY Velinov L Mateev and Y Tassev Ionizationeffect of nuclei with solar and galactic origin in the earthatmosphere during GLE 69 on 20 January 2005 J Atmos SolTerr Phys 89 1ndash7 2012

Nestorov G Physics of the Lower Ionosphere Publ House of theBulg Acad Sci Sofia 1969

OrsquoBrien K Cosmic-ray propagation in the atmosphere Il NuovoCimento A 3 (4) 521ndash547 1971

Olson DE Interpretation of the solar influence on the atmosphericelectrical parameters in Weather and Climate Responses to SolarVariations edited by BM McCormac Assoc Univ PressBoulder CO 483ndash488 1983

Porter HS CH Jackman and AES Green Efficiencies forproduction of atomic nitrogen and oxygen by relativistic protonimpact in air J Chem Phys 65 154ndash167 1976

Press WH BP Flannery SA Teukolsky and WT VetterlingNumerical Recipes in C++ ndash the Art of Scientific ComputingCambridge University Press Cambridge 1991

Reid GS A study of enhanced ionisation produced by solarprotons during a polar cap absorption event J Geophys Res 664071 1961

Rycroft MJ S Israelson and C Price The global atmosphericelectrical circuit solar activity and climate change J Atmos SolTerr Phys 62 (17ndash18) 1563ndash1576 2000

Rycroft MJ A Odzimek NF Arnold M Fullekrug A Kulakand T Neubert New model simulations of the global atmosphericelectrical circuit driven by thunderstorms and electrified showerclouds the roles of lightning and sprites J Atmos Sol TerrPhys 69 2485ndash2509 2007

Scherer K H Fichtner T Borrmann J Beer L Desorgher EFlukiger and H-J Fahr Interstellar-terrestrial relations variablecosmic environments the dynamic heliosphere and their imprintson terrestrial archives and climate Space Sci Rev 127 327ndash4652007

Seo ES JF Ormes RE Streitmatter SJ Stochaj WV Joneset al Measurement of cosmic-ray proton and helium spectraduring the 1987 solar minimum Astrophys J 371 763 1991

Shikaze Y S Haino K Abe H Fuke T Hams et al Measure-ments of 02ndash20 GeVn cosmic-ray proton and helium spectrafrom 1997 through 2002 with the BESS spectrometer AstropartPhys 28 154 2007

Simpson JA Cosmic radiation particle astrophysics in theheliosphere in Frontiers in Cosmic Physics edited by RBMendell and AI Mincer Ann N York Acad Sci 655 951992

Singh AK D Siingh and RP Singh Space weather physicseffects and predictability Surv Geophys 31 581ndash638 2010

Singh AK D Singh and RP Singh Impact of galactic cosmicrays on Earthrsquos atmosphere and human health Atmos Environ45 3806ndash3818 2011

Sternheimer R in Fundamental Principles and Methods of ParticleDetection Methods of Experimental Physics vol V A NuclearPhysics edited by LCL Yuan and CS Wu New YorkLondon Academic Press 1961


A14-p15

Svensmark H Influence of cosmic rays on Earthrsquos climate PhysRev Lett 81 (22) 5027ndash5030 1998

Tinsley BA Influence of solar wind on the global electric circuitand inferred effects on cloud microphysics temperature anddynamics in the troposphere Space Sci Rev 94 (1ndash2) 231ndash2582000

Tinsley BA A working hypothesis for connections betweenelectrically-induced changes in cloud microphysics and stormvorticity with possible effects on circulation Adv Space Res 50791ndash805 2012

Tinsley BA and RA Heelis Correlations of atmosphericdynamics with solar activity evidence for a connection via thesolar wind atmospheric electricity and cloud microphysics JGeophys Res 98 10375ndash10384 1993

Tinsley BA and L Zhou Initial results of a global circuit modelwith stratospheric and tropospheric aerosols J GeophysRes111 D16205 2006

Tonev PT and PIY Velinov Model study of the influence of solarwind parameters on electric currents and fields in middleatmosphere at high latitudes CR Acad Bulg Sci 64 (12)1733ndash1742 2011

Tsagouri I A Belehaki N Bergeot C Cid V Delouille et alProgress in space weather modeling in an operational environ-ment J Space Weather Space Clim 3 in press 2013

Usoskin IG OG Gladysheva and GA Kovaltsov Cosmic rayinduced ionization in the atmosphere spatial and temporalchanges J Atmos Sol Terr Phys 66 1791ndash1796 2004

Usoskin I K Alanko-Huotari G Kovaltsov and K MursulaHeliospheric modulation of cosmic rays Monthly Reconstructionfor 1951ndash2004 J Geophys Res 110 (A12) CiteID A121082005

Usoskin I L Desorgher PIY Velinov M Storini E FlueckigerR Buetikofer and GA Kovalstov in Solar and Galactic CosmicRays in the Earthrsquos Atmosphere Developing the Scientific Basisfor Monitoring Modeling and Predicting Space Weather editedby Lilensten J COST 724 Final Report COST Office Brussels127ndash135 2008

Usoskin I L Desorgher PIY Velinov M Storini E Flueckiger RBuetikofer and GA Kovalstov Solar and galactic cosmic rays inthe Earthrsquos atmosphere Acta Geophys 57 (1March) 88ndash1012009

Usoskin I and G Kovaltsov Cosmic ray induced ionization in theatmosphere full modeling and practical applications J GeophysRes 111 D21206 2006

Usoskin IG GA Kovaltsov and IA Mironova Cosmic rayinduced ionization model CRAC CRII an extension to the upperatmosphere J Geophys Res 115 D10302 2010

Usoskin IG GA Kovaltsov IA Mironova AJ Tylka and WFDietrich Ionization effect of solar particle GLE events in low andmiddle atmosphere Atmos Chem Phys 11 1979ndash1988 2011

Vainio R L Desorgher D Heynderickx M Storini E Fluckigeret al Dynamics of the Earthrsquos particle radiation environmentSpace Sci Rev 147 187ndash231 2009

Van Allen JA Physics and Medicine of the Upper AtmosphereChapter 14 Albuquerque Univ N Mexico Press 1952

Velinov PIY An expression for ionospheric electron productionrate by cosmic rays CR Acad Bulg Sci 19 (2) 109ndash1121966

Velinov PIY Some results of the rate of electron production in thecosmic layer of low ionosphere CR Acad Bulg Sci 20 (11)1141ndash1144 1967a

Velinov PIY On electron production rates in the polar capionosphere due to solar cosmic rays CR Acad Bulg Sci 20(12) 1278ndash1278 1967b

Velinov PIY On ionization in the ionospheric D region by galacticand solar cosmic rays J Atmos Terr Phys 30 1891ndash1905 1968

Velinov PIY Solar cosmic ray ionization in the low ionosphere JAtmos Terr Phys 32 139ndash147 1970

Velinov PIY Cosmic ray ionization rates in the planetaryatmospheres J Atmos Terr Phys 36 359ndash362 1974

Velinov PIY Effect of the Anomalous Cosmic Ray (ACR)component on the high-latitude ionosphere CR Acad BulgSci 44 (2) 33ndash36 1991

Velinov PIY and L Mateev Response of the middle atmosphereon galactic cosmic ray influence Geomagn Aeronomy 30 (4)593ndash598 1990

Velinov PIY and L Mateev Improved cosmic ray ionizationmodel for the system ionosphere - atmosphere Calculation ofelectron production rate profiles J Atmos Sol Terr Phys 70574ndash582 2008a

Velinov PIY and L Mateev Analytical approach to cosmic rayionization by nuclei with charge Z in the middle atmosphere ndashdistribution of galactic CR effects J Adv Space Res 42 1586ndash1592 2008b

Velinov PIY and A Mishev Cosmic ray induced ionization in theatmosphere estimated with CORSIKA code simulations CRAcad Bulg Sci 60 (5) 495ndash502 2007

Velinov PIY and A Mishev Cosmic ray induced ionization in theupper middle and lower atmosphere simulated with CORSIKAcode in Proceedings of the 30th International Cosmic RayConference Merida Mexico 3ndash11 July 2007 edited by RCaballero et al Universidad Nacional Autonoma de MexicoMexico City Mexico 1 (SH) 749ndash752 2008a

Velinov PIY and A Mishev Solar cosmic ray induced ionizationin the Earthrsquos atmosphere obtained with CORSIKA code simu-lations CR Acad Bulg Sci 61 (7) 927ndash932 2008b

Velinov PIY and P Tonev Electric currents from thunderstorms tothe ionosphere during a solar cycle quasi-static modeling of thecoupling mechanism J Adv Space Res 42 569ndash1575 2008

Velinov PIY G Nestorov and L Dorman Cosmic Ray Influenceon the Ionosphere and on the Radio-Wave Propagation BASPubl House Sofia 1974

Velinov PIY M Buchvarova L Mateev and H Ruder Determi-nation of electron production rates caused by cosmic ray particlesin ionospheres of terrestrial planets J Adv Space Res 27 (11)1901ndash1908 2001

Velinov PIY H Ruder L Mateev M Buchvarova and V KostovMethod for calculation of ionization profiles caused by cosmicrays in giant planet ionospheres from Jovian group J Adv SpaceRes 33 232ndash239 2004

Velinov PIY L Mateev and N Kilifarska 3D model for cosmicray planetary ionization in the middle atmosphere AnnalGeophys 23 (9) 3043ndash3046 2005a

Velinov PIY H Ruder and L Mateev Analytical model forcosmic ray ionization by nuclei with charge Z in the lowerionosphere and middle atmosphere CR Acad Bulg Sci 58897ndash902 2005b

Velinov PIY H Ruder and L Mateev Energy interval coupling inimproved cosmic ray ionization model with three intervals inionization losses function for the system atmosphereionosphereCR Acad Bulg Sci 59 847ndash854 2006

Velinov PIY L Mateev and H Ruder Generalized model ofionization profiles due to cosmic ray particles with charge Z inplanetary ionospheres and atmospheres with 5 energy intervalapproximation of the ionization losses function CR Acad BulgSci 61 (1) 133ndash146 2008

Velinov PIY A Mishev and L Mateev Model for inducedionization by galactic cosmic rays in the Earth atmosphere andionosphere J Adv Space Res 44 1002ndash1007 2009

Velinov PIY S Asenovski and L Mateev Simulation of cosmicray ionization profiles in the middle atmosphere and lowerionosphere on account of characteristic energy intervals CRAcad Bulg Sci 64 (9) 1303ndash1310 2011a

Velinov PIY A Mishev S Asenovski and L Mateev Newoperational models for cosmic ray ionization in space physicsBulg J Phys 38 264ndash273 2011b

Velinov PIY S Asenovski and L Mateev Improved cosmic rayionization model for ionosphere and atmosphere (CORIMIA)with account of 6 characteristic intervals CR Acad Bulg Sci65 (8) 1135ndash1144 2012


A14-p16

Vitt FM and CH Jackman A comparison of sources of oddnitrogen production from 1974 through 1993 in the Earthrsquos middleatmosphere as calculated using a two-dimensional model JGeophys Res 101 6729ndash6740 1996

Weimer DR A flexible IMF dependent model of high latitudeelectric potential having lsquolsquospace weatherrsquorsquo applications GeophysRes Lett 23 2549ndash2552 1996

Williams ER The global electrical circuit a review Atmos Res91 140ndash152 2009

Wissing JM and MB Kallenrode Atmospheric IonizationModule Osnabruck (AIMOS) a 3D model to determine atmo-spheric ionization by energetic charged particles from differentpopulations J Geophys Res 114 A06104 2009

Wolfram Research Inc Mathematica Version 70 Champaign IL2008

Cite this article as Velinov P Asenovski S Kudela K Lastovicka J Mateev L et al Impact of cosmic rays and solar energeticparticles on the Earthrsquos ionosphere and atmosphere J Space Weather Space Clim 2013 3 A14


A14-p17

Introduction

Model CORIMIA for CR ionization above 30km

Model description

CR spectra

Results for GCR ionization

Results for ACR ionization

Results for SEP ionization

Recent Monte-Carlo models for CR ionization

An extension of CRAC ionization model to the upper atmosphere

Effect of model assumptions on computations of CR ionization in atmosphere

Normalization of ionization yield function

Ionization effect in the atmosphere during GLE

Applications of ionization models for estimation of CR influence on atmosphere

CR influence on minor atmospheric constituents

CR influence on atmospheric electric processes

CR influence on technological systems

Conclusion

Acknowledgements

References

made by Velinov (1970 1974) Dorman amp Kozin (1983)Velinov amp Mateev (1990) etc

However at altitudes below 30 km the primary cosmic raysinitiate a nucleonic-electromagnetic cascade in the atmospherewith the main energy losses resulting in ionization dissociationand excitation of molecules (see eg Dorman 2004) A princi-pally new approach is the full Monte-Carlo CORSIKA (COs-mic Ray SImulations for KAscade) simulation tool used formodelling the atmospheric nucleonic-electromagnetic cascade(Heck et al 1998)

In the framework of the previous COST-724 action (2003ndash2007) three numerical CR ionization models have been devel-oped (Usoskin et al 2008 2009)

1 The Sofia model includes an analytical approximation ofthe direct ionization by CR primaries above 30 km(Velinov et al 2004 2005a 2005b 2006 2008Buchvarova amp Velinov 2005) as well as the CORSIKAMonte-Carlo package extended by FLUKA package tosimulate the low-energy nuclear interactions below30 km (Velinov amp Mishev 2007 2008a 2008b Mishevamp Velinov 2007 2008)

2 The Oulu CRAC (Cosmic Ray Atmospheric Cascade)model is based on the CORSIKAFLUKA Monte-Carlosimulations and explicitly accounting for direct ionizationby primary CR particles (Usoskin et al 2004 2005Usoskin amp Kovaltsov 2006 Usoskin et al 2008 2009)

3 The Bern model (ATMOCOSMICSPLANETOCOS-MICS code) is based on the GEANT-4 Monte-Carlo sim-ulation package (Agostinelli et al 2003) The mainresults are obtained by Desorgher et al (2005) Schereret al (2007) Usoskin et al (2008 2009) etc

Both codes (CORSIKA and GEANT-4) permit realisticstudy of the cascade evolution in the atmosphere simulatingthe interactions and decays of various nuclei hadrons muonselectrons and photons The result of the simulations is detailedinformation about the type energy momenta location and arri-val time of the produced secondary particles at given selectedaltitude above sea level (asl) (Usoskin et al 2008 2009)

Here we present some developments of these models (inparticular the Sofia model) during the COST ES0803 action(2008ndash2012) their validation and comparison with direct obser-vations and other results We also discuss effects caused bysolar and galactic particles in the atmosphere

2 Model CORIMIA for CR ionization above 30 km

In contrast to the lower atmosphere the ionization of the middleand upper atmosphere where the cascade is not developedallows a relatively simple analytical solution This is relatedto the fact that the atmospheric depth at the altitude of 30 kmis about 10 gcm2 (at 50 km is 1 gcm2) which is much lessthan the nuclear free path of protons and a particles (70and 30 gcm2 respectively) Therefore one can neglect nuclearinteractions in the middle atmosphere above 30 km (upperstratosphere and ionosphere) and consider only ionizationlosses of the primary CR particles (Velinov et al 1974 Usoskinet al 2009) Moreover for the altitude above 50 km one can

further neglect changes of the energy of energetic particles thusreducing the computation of CR ionization to an analytical thintarget model (Velinov 1966 1967a 1968)

In the altitude range from 25ndash30 to 50 km an intermediatetarget model needs to be used that accounts also for the parti-clersquos deceleration due to ionization losses (eg Velinov 1967bVelinov amp Mateev 1990) This model was applied for calcula-tion of electron density and atmospheric electrical conductivi-ties in the middle atmosphere for different particles GCRACR and SEP The intermediate target ionization model wasfurther developed with account of the Chapman function valuesfor the inclined penetrating particles in the spherical atmosphere(Velinov amp Mateev 2008a 2008b Velinov et al 2008 2009)

The program CORIMIA (COsmic Ray Ionization Modelfor Ionosphere and Atmosphere) is developed for calculationof the electron and ion production rate profiles due to cosmicrays using ionization losses (Bohr-Bethe-Bloch function)approximation in six characteristic energy intervals includingthe charge decrease interval for electron capturing (Velinovet al 2011a 2011b 2012)

Here some of results of the detailed model for calculation ofCR ionization rates q ndash the number of electron-ion pairs incm3 per second at given altitude h (km) in the ionosphereand middle atmosphere are presented The mathematicalexpression of the fully operational program CORIMIA is thefollowing (Velinov 1966)

q heth THORN frac14X

i

qi heth THORN

frac14 1

Q

Xi

Z 1

Ei

Z 2p

Afrac140

Z p2thornh

hfrac140Di Eeth THORN dE

dh

i

sin h dh dA dE eth1THORNwhere Di(E) is the CR differential spectrum(cm2 s1 st1 MeV1) (dEdh) are ionization losses(Sternheimer 1961) of particles of type i A is the azimuthangle h is the angle towards the vertical Dh takes intoaccount that at a given height h the particles can penetratefrom the space angle (0 hmax = 90 + Dh) which is greaterthan the upper hemisphere angle (0 90) for flat model Ei

are the energy cut-off which correspond to the geomagneticcut-off rigidity Rc The summation in the ionization integral(1) is made on the groups of nuclei (i = 1 6) protonsp Helium (a particles) Light L (3 Z 5) Medium M(6 Z 9) Heavy H (Z 10) and Very Heavy VH (Z 20) nuclei in the composition of cosmic rays Z is the chargeof the nuclei Q = 35 eV is the energy which is necessary forformation of one electron-ion pair (Porter et al 1976)

21 Model description

Five main characteristic energy intervals and one chargedecrease interval for electron capturing in the approximationof ionization losses (MeV g1 cm2) according to Bohr-Bethe-Bloch formula using experimental data (Sternheimer 1961)are introduced (Velinov et al 2008 2009) The approximationfor CR nuclei (Z gt 1) is the following (Velinov et al 2011b2012)


A14-p2




22 CR spectra




b eth4THORN









1

qdEdhfrac14








eth2THORN


A14-p3












A14-p4

















A14-p5















A14-p6




E0















A14-p7







0 200 400 600 800 1000101

102

103

104

105

0 200 400 600 800 1000

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

Yie

ld fu

nctio

n Y

[ion

pai

rs s

r cm

2 g-1]



B

Yie

ld fu

nctio

n Y

[Ion

pai

rs s

r cm

2 g-1]




A






A14-p8



0 200

40x10 4

80x10 4

12x10 5

0 300

20x105

40x105

60x105

0 200 400

00

20x106

40x106

Ioni

zatio

n Yi

eld

func

tion

Y [s

r cm

2 g-1]


1 GeVProtons

10 GeV CB


100 GeV

A


10 100 1000103

104

105

106

10 100 1000

106

107

10 100

10 0

10 1

10 2

10 3

10 4

10 5

10 6

10 GeVnucleon



YIron

YOxygen

YHelium

Norm

alize

d Io

niza

tion

Yiel

d fu

nctio

n Y

[cm

2 g-1 sr

]



A14-p9





0

20

40

100 101 102 103

0

20

40

10-6 10-5 10-4 10-3 10-2 10-1 100 101 102

0

5

10

15

20

25

30

35

40

101 102 103 104 105-5

0

5

10

15

20

25

30

35

40

101 102 103 104-5

0

5

10

15

20

25

30

35

40


Altit

ude

[ km

as

l]



Altit

ude

[ km

as

l]

BA40N

0800 UT 2300 UT

2300 UT0800 UT

80N

DC



A14-p10











A14-p11













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References




22 CR spectra




b eth4THORN









1

qdEdhfrac14








eth2THORN


A14-p3












A14-p4

















A14-p5















A14-p6




E0















A14-p7







0 200 400 600 800 1000101

102

103

104

105

0 200 400 600 800 1000

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

Yie

ld fu

nctio

n Y

[ion

pai

rs s

r cm

2 g-1]



B

Yie

ld fu

nctio

n Y

[Ion

pai

rs s

r cm

2 g-1]




A






A14-p8



0 200

40x10 4

80x10 4

12x10 5

0 300

20x105

40x105

60x105

0 200 400

00

20x106

40x106

Ioni

zatio

n Yi

eld

func

tion

Y [s

r cm

2 g-1]


1 GeVProtons

10 GeV CB


100 GeV

A


10 100 1000103

104

105

106

10 100 1000

106

107

10 100

10 0

10 1

10 2

10 3

10 4

10 5

10 6

10 GeVnucleon



YIron

YOxygen

YHelium

Norm

alize

d Io

niza

tion

Yiel

d fu

nctio

n Y

[cm

2 g-1 sr

]



A14-p9





0

20

40

100 101 102 103

0

20

40

10-6 10-5 10-4 10-3 10-2 10-1 100 101 102

0

5

10

15

20

25

30

35

40

101 102 103 104 105-5

0

5

10

15

20

25

30

35

40

101 102 103 104-5

0

5

10

15

20

25

30

35

40


Altit

ude

[ km

as

l]



Altit

ude

[ km

as

l]

BA40N

0800 UT 2300 UT

2300 UT0800 UT

80N

DC



A14-p10











A14-p11













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References












A14-p4

















A14-p5















A14-p6




E0















A14-p7







0 200 400 600 800 1000101

102

103

104

105

0 200 400 600 800 1000

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

Yie

ld fu

nctio

n Y

[ion

pai

rs s

r cm

2 g-1]



B

Yie

ld fu

nctio

n Y

[Ion

pai

rs s

r cm

2 g-1]




A






A14-p8



0 200

40x10 4

80x10 4

12x10 5

0 300

20x105

40x105

60x105

0 200 400

00

20x106

40x106

Ioni

zatio

n Yi

eld

func

tion

Y [s

r cm

2 g-1]


1 GeVProtons

10 GeV CB


100 GeV

A


10 100 1000103

104

105

106

10 100 1000

106

107

10 100

10 0

10 1

10 2

10 3

10 4

10 5

10 6

10 GeVnucleon



YIron

YOxygen

YHelium

Norm

alize

d Io

niza

tion

Yiel

d fu

nctio

n Y

[cm

2 g-1 sr

]



A14-p9





0

20

40

100 101 102 103

0

20

40

10-6 10-5 10-4 10-3 10-2 10-1 100 101 102

0

5

10

15

20

25

30

35

40

101 102 103 104 105-5

0

5

10

15

20

25

30

35

40

101 102 103 104-5

0

5

10

15

20

25

30

35

40


Altit

ude

[ km

as

l]



Altit

ude

[ km

as

l]

BA40N

0800 UT 2300 UT

2300 UT0800 UT

80N

DC



A14-p10











A14-p11













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References

















A14-p5















A14-p6




E0















A14-p7







0 200 400 600 800 1000101

102

103

104

105

0 200 400 600 800 1000

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

Yie

ld fu

nctio

n Y

[ion

pai

rs s

r cm

2 g-1]



B

Yie

ld fu

nctio

n Y

[Ion

pai

rs s

r cm

2 g-1]




A






A14-p8



0 200

40x10 4

80x10 4

12x10 5

0 300

20x105

40x105

60x105

0 200 400

00

20x106

40x106

Ioni

zatio

n Yi

eld

func

tion

Y [s

r cm

2 g-1]


1 GeVProtons

10 GeV CB


100 GeV

A


10 100 1000103

104

105

106

10 100 1000

106

107

10 100

10 0

10 1

10 2

10 3

10 4

10 5

10 6

10 GeVnucleon



YIron

YOxygen

YHelium

Norm

alize

d Io

niza

tion

Yiel

d fu

nctio

n Y

[cm

2 g-1 sr

]



A14-p9





0

20

40

100 101 102 103

0

20

40

10-6 10-5 10-4 10-3 10-2 10-1 100 101 102

0

5

10

15

20

25

30

35

40

101 102 103 104 105-5

0

5

10

15

20

25

30

35

40

101 102 103 104-5

0

5

10

15

20

25

30

35

40


Altit

ude

[ km

as

l]



Altit

ude

[ km

as

l]

BA40N

0800 UT 2300 UT

2300 UT0800 UT

80N

DC



A14-p10











A14-p11













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References















A14-p6




E0















A14-p7







0 200 400 600 800 1000101

102

103

104

105

0 200 400 600 800 1000

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

Yie

ld fu

nctio

n Y

[ion

pai

rs s

r cm

2 g-1]



B

Yie

ld fu

nctio

n Y

[Ion

pai

rs s

r cm

2 g-1]




A






A14-p8



0 200

40x10 4

80x10 4

12x10 5

0 300

20x105

40x105

60x105

0 200 400

00

20x106

40x106

Ioni

zatio

n Yi

eld

func

tion

Y [s

r cm

2 g-1]


1 GeVProtons

10 GeV CB


100 GeV

A


10 100 1000103

104

105

106

10 100 1000

106

107

10 100

10 0

10 1

10 2

10 3

10 4

10 5

10 6

10 GeVnucleon



YIron

YOxygen

YHelium

Norm

alize

d Io

niza

tion

Yiel

d fu

nctio

n Y

[cm

2 g-1 sr

]



A14-p9





0

20

40

100 101 102 103

0

20

40

10-6 10-5 10-4 10-3 10-2 10-1 100 101 102

0

5

10

15

20

25

30

35

40

101 102 103 104 105-5

0

5

10

15

20

25

30

35

40

101 102 103 104-5

0

5

10

15

20

25

30

35

40


Altit

ude

[ km

as

l]



Altit

ude

[ km

as

l]

BA40N

0800 UT 2300 UT

2300 UT0800 UT

80N

DC



A14-p10











A14-p11













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References




E0















A14-p7







0 200 400 600 800 1000101

102

103

104

105

0 200 400 600 800 1000

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

Yie

ld fu

nctio

n Y

[ion

pai

rs s

r cm

2 g-1]



B

Yie

ld fu

nctio

n Y

[Ion

pai

rs s

r cm

2 g-1]




A






A14-p8



0 200

40x10 4

80x10 4

12x10 5

0 300

20x105

40x105

60x105

0 200 400

00

20x106

40x106

Ioni

zatio

n Yi

eld

func

tion

Y [s

r cm

2 g-1]


1 GeVProtons

10 GeV CB


100 GeV

A


10 100 1000103

104

105

106

10 100 1000

106

107

10 100

10 0

10 1

10 2

10 3

10 4

10 5

10 6

10 GeVnucleon



YIron

YOxygen

YHelium

Norm

alize

d Io

niza

tion

Yiel

d fu

nctio

n Y

[cm

2 g-1 sr

]



A14-p9





0

20

40

100 101 102 103

0

20

40

10-6 10-5 10-4 10-3 10-2 10-1 100 101 102

0

5

10

15

20

25

30

35

40

101 102 103 104 105-5

0

5

10

15

20

25

30

35

40

101 102 103 104-5

0

5

10

15

20

25

30

35

40


Altit

ude

[ km

as

l]



Altit

ude

[ km

as

l]

BA40N

0800 UT 2300 UT

2300 UT0800 UT

80N

DC



A14-p10











A14-p11













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References







0 200 400 600 800 1000101

102

103

104

105

0 200 400 600 800 1000

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

0 200 400 600 800 1000

102

103

104

105

106

Yie

ld fu

nctio

n Y

[ion

pai

rs s

r cm

2 g-1]



B

Yie

ld fu

nctio

n Y

[Ion

pai

rs s

r cm

2 g-1]




A






A14-p8



0 200

40x10 4

80x10 4

12x10 5

0 300

20x105

40x105

60x105

0 200 400

00

20x106

40x106

Ioni

zatio

n Yi

eld

func

tion

Y [s

r cm

2 g-1]


1 GeVProtons

10 GeV CB


100 GeV

A


10 100 1000103

104

105

106

10 100 1000

106

107

10 100

10 0

10 1

10 2

10 3

10 4

10 5

10 6

10 GeVnucleon



YIron

YOxygen

YHelium

Norm

alize

d Io

niza

tion

Yiel

d fu

nctio

n Y

[cm

2 g-1 sr

]



A14-p9





0

20

40

100 101 102 103

0

20

40

10-6 10-5 10-4 10-3 10-2 10-1 100 101 102

0

5

10

15

20

25

30

35

40

101 102 103 104 105-5

0

5

10

15

20

25

30

35

40

101 102 103 104-5

0

5

10

15

20

25

30

35

40


Altit

ude

[ km

as

l]



Altit

ude

[ km

as

l]

BA40N

0800 UT 2300 UT

2300 UT0800 UT

80N

DC



A14-p10











A14-p11













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References



0 200

40x10 4

80x10 4

12x10 5

0 300

20x105

40x105

60x105

0 200 400

00

20x106

40x106

Ioni

zatio

n Yi

eld

func

tion

Y [s

r cm

2 g-1]


1 GeVProtons

10 GeV CB


100 GeV

A


10 100 1000103

104

105

106

10 100 1000

106

107

10 100

10 0

10 1

10 2

10 3

10 4

10 5

10 6

10 GeVnucleon



YIron

YOxygen

YHelium

Norm

alize

d Io

niza

tion

Yiel

d fu

nctio

n Y

[cm

2 g-1 sr

]



A14-p9





0

20

40

100 101 102 103

0

20

40

10-6 10-5 10-4 10-3 10-2 10-1 100 101 102

0

5

10

15

20

25

30

35

40

101 102 103 104 105-5

0

5

10

15

20

25

30

35

40

101 102 103 104-5

0

5

10

15

20

25

30

35

40


Altit

ude

[ km

as

l]



Altit

ude

[ km

as

l]

BA40N

0800 UT 2300 UT

2300 UT0800 UT

80N

DC



A14-p10











A14-p11













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References





0

20

40

100 101 102 103

0

20

40

10-6 10-5 10-4 10-3 10-2 10-1 100 101 102

0

5

10

15

20

25

30

35

40

101 102 103 104 105-5

0

5

10

15

20

25

30

35

40

101 102 103 104-5

0

5

10

15

20

25

30

35

40


Altit

ude

[ km

as

l]



Altit

ude

[ km

as

l]

BA40N

0800 UT 2300 UT

2300 UT0800 UT

80N

DC



A14-p10











A14-p11













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References











A14-p11













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References













A14-p12








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References








5 Conclusion










A14-p13





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References





References
































A14-p14











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References











































A14-p15











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References











































A14-p16








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References








A14-p17

Introduction


Model description

CR spectra













Conclusion

Acknowledgements

References

Impact of cosmic rays and solar energetic particles on the ... · Impact of cosmic rays and solar...

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