Mike Lockwood STFC/Rutherford Appleton Laboratory & Southampton University
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Transcript of Mike Lockwood STFC/Rutherford Appleton Laboratory & Southampton University
Mike Lockwood
STFC/Rutherford Appleton Laboratory & Southampton University
Our life-giving star: the flow of energy from the Sun to the Earth
BA Festival of Science, York, Monday 10th September 2007
How the Sun Influences Modern Life
How the Sun Influences Modern Life
Galactic Cosmic Rays
Solar Energetic Particles
Satellite Damage
Human Spaceflight Hazards
Sun and Climate Change
How the Sun Influences Modern Life
Galactic Cosmic Rays
Solar Energetic Particles
Satellite Damage
Human Spaceflight Hazards
Sun and Climate Change
The Solar Wind Plasma
A Coronograph is a man-made eclipse with an occulting disc
blocking out the visible surface of the Sun (the Photosphere).
Allows us to observe the hot solar atmosphere, the Corona
Continuous outflow of ionised gas (“plasma”), The Solar
Wind, 1014 kg per day
Events CMEs eject ~1013 kg at about 350 km s-1
(PS watch the comet!)
The “Frozen-in flux” Theorem
Charged particle motions
Magnetic Field
B
( by definition of B )
Lorentz ForceB
B
Emergence of Coronal Magnetic Flux
Loops of magnetic flux
emerge through the surface in
active (sunspot) regions
Some of this flux is “open” rises through
the corona and is frozen-in to the solar wind
outflow
Parker Spiral(an example of frozen-in)
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Parker Spiral(an example of frozen-in)
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Parker Spiral(an example of frozen-in)
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Parker Spiral(an example of frozen-in)
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Parker Spiral(an example of frozen-in)
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Parker Spiral(an example of frozen-in)
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Parker Spiral(an example of frozen-in)
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Parker Spiral(an example of frozen-in)
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Parker Spiral(an example of frozen-in)
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Parker Spiral(an example of frozen-in)
Sun
Solar wind flow is radial
Solar rotation and radial solar wind generates a Parker spiral field structure
Field is “frozen-in” to the solar wind flow
Parker Spiral(an example of frozen-in)
Interplanetary scintillation is the “twinkling” if radio stars caused by irregularities in the solar wind Tomographic reconstructionfrom interplanetary scintillations
Solar rotation and radial solar wind generates a Parker spiral field structure
Co-rotates with the solar corona (every 27 days in Earth’s frame)
Parker Spiral(an example of frozen-in)
A Stellar Heliosphere
interstellar wind
bow shock
heliopause
heliosheath
Hubble observations of the heliosheath behind the bow shock where the heliosphere of LL Ori heliosphere meets its (dense) local interstellar wind in the Orion nebula
Galactic Cosmic Rays
The coronal source flux is dragged out by the solar wind flow to
give the heliospheric
field which shields Earth from galactic cosmic rays
Cosmic Rays Anticorrelation with sunspot numbers
Sunspot Number
Huancauyo – Hawaii neutron monitor counts
(>13GV)
Climax neutron monitor counts
(>3GV)
A Stellar HeliosphereCosmic ray tracks in a bubble chamber
How the Sun Influences Modern Life
Galactic Cosmic Rays
Solar Energetic Particles
Satellite Damage
Human Spaceflight Hazards
Sun and Climate Change
Solar Energetic Protons(SEPs)
Energised at the shock fronts of CMEs (and CIRs)
Follow heliospheric field lines
Seen here striking the imager CCD plate of the LASCO coronograph on the SoHO spacecraft
Sun
Parker Spiral(an example of frozen-in)
Sun
SEPs generated at front of CMEs
Guided along IMF
Parker Spiral(an example of frozen-in)
CME
How the Sun Influences Modern Life
Galactic Cosmic Rays
Solar Energetic Particles
Satellite Damage
Human Spaceflight Hazards
Sun and Climate Change
Spacecraft Damage
spacecraft
penetrating radiation
electronics box
sensitive component
charge buried in insulator can discharge
floating circuit trace can collect charge and
discharge
radiation environment damage:
Surface charging 0.1 – 100 keV electrons
Single event upsets MeV ions
Cumulative radiation dose Limits spacecraft lifetime
Internal charging (“deep dielectric charging”)
MeV electrons
Tomographic reconstruction from interplanetary scintillations
The Bastille Day Storm CMEs seen by IPS
► Ground-level enhancement (GLE) of solar energetic particles seen between Forbush decreases of galactic cosmic rays caused by shielding by the two CMEs
► Here seen at stations in both poles (McMurdo and Thule)
Neutron Monitor counts
Forbush decrease caused by 1st CME
GLEForbush decrease caused by
CME associated with GLE
nm
co
un
ts
The Bastille Day Storm GCRs and SEPs
▲▼ = Single event upsets (SEUs) suffered by satellites in geostationary and high altitude orbits
several satellites were powered down to protect them
The Bastille Day Storm SEPs seen at Geostationary Orbit
How the Sun Influences Modern Life
Galactic Cosmic Rays
Solar Energetic Particles
Satellite Damage
Human Spaceflight Hazards
Sun and Climate Change
BIOLOGICAL EFFECTSBIOLOGICAL EFFECTS
Heavy ions
breaks molecular links
&
can cause nuclear reactions so (e.g.) C converted to N and O in molecules
The Apollo Missions
Above annual dose
Above annual dose
SEPs: just how lucky were the lunar astronauts?
SEPs during the era of the Apollo Missions
Raised cancer risk
Raised cancer risk
Severe radiation sickness
Severe radiation sickness
Instantly fatal
Instantly fatal
Average annual dose at Earth’s surface
Max. annual dose for a radiation worker
SEPs: what’s the space weather been like?
Above annual doseRaised cancer risk
Severe radiation sickness
Instantly fatal
SEPs and Galactic cosmic rays since the Apollo Missions
How the Sun Influences Modern Life
Galactic Cosmic Rays
Solar Energetic Particles
Satellite Damage
Human Spaceflight Hazards
Sun and Climate Change
Total Solar Irradiance
best composite of observations (by PMOD, Davos)
shows 0.1% solar cycle variation
damped out by large thermal capacity of Earth’s oceans but are there century- scale changes which would not be damped?
Total solar irradiance changes and magnetic field emergence
Dark sunspots and bright faculae are where magnetic field threads the solar surface
TSI reconstructions
Open Solar Flux, FS
TSI (for 3 assumptions for the Maunder Minimum)
A. [Fp]MM = [Fp]now
B. [Fp]MM = 0
C. [Fp]MM = [Fp]now /2
Recent trends - revealed by averaging over solar cycle length, L
► sunspot number, R
► FS from IMF data
► GCR counts C (Climax n.m.)
► PMOD composite of TSI data
► solar cycle length, L
running mean over T=[9:(1/4):13] yrs
running mean over T=L yrs