Solar radio emission at solar maximum
description
Transcript of Solar radio emission at solar maximum
Solar radio emission at solar maximum
CME development in the corona
M. Pick, D. Maia and Ch. MarquéLESIA, Observatoire de Paris
Cospar 2002
Context
• Nançay Radioheliograph (NRH)– Multiwavelength observations (dm-m)– High cadence < second
• Radio survey– NRH and WAVES/WIND spectrograph (dam-km)
– Use for many objectives
• Coordinated observations– SOHO, TRACE, ACE, WIND, YOHKOH, Ulysse and
Ground facilities (Halpha and radio)– Interest of disk observations
Context
• Flare/CME events– Non thermal emission– Energetic electrons tracers of B field– Search for weak emission often occulted by
NT emission
• CMEs in the absence of large flares– Association with noise storms (NT emission)– Thermal emission and eruptive prominences
Radio signatures
Maia et al., 1999
Fast progression in latitudeFull extend: 9 min ≥1000 km/sSuccessive loop interactionsSuper-alfvenic disturbance
CME lateral expansion
Full expansion < 10 min.Signatures of these interactions step by step. Follow in space and time CME progression
Maia et al., 1999November 06 1997
On-disk event
Pohjolainen et al., 2001
Moreton wavecoronal shock waveM-type IIAssociation in time and space
Full expansion 15 min.
Bastille event
Maia et al. 2001
Proxies of CMEs Lateral progression of CME development in the early stage Full development reached within 10 min. or often lessSimilar shape seen by NRH-LASCO(Gopalswamy and Kundu,1992) Identification of different scenarios Starting point :study of individual events
Maia, Aulanier, S. J. Wang et al., 2002
Cospatial south loopsEast and West Quasi simultaneous
South part of the CME: Breakout type instability Null point 26OOO km, B reconnection, MHD wave triggers activity. S Loops pushing up and interconnecting with multiple B systems.North part of the CME (F sources):Null points western part 6000km
Other class of CME development
Coronal null point
October 25, 2000
Radio signature ofB reconfiguration
Bastian et al., 2001: « Radio CME »Maia et al., 2001 Plasma front , CME-Driven shock
Dynamics of CMEs: Detection of weak NT emissions
Gyrosynchrotron emissionRadio V 1570 ± 390 km/sLASCO V 980± 70 km/sDeacceleration in the corona <4 Rs (Gopalswamy et al., 02)
C2
NRH
C3
C2
Thermal emission and CME development
Marqué et al., 2002
Type III like bursts above the parasitic polarity
Radio depression appears ~40 mn later
Dynamical continuity radio depression and CME substructures
Continuity with radio depression CAVITYOn-disk and limb observations Traces the motion at low altitudeLink between EIT and LASCO
CONCLUSION
Multifrequency radio imaging observationsOn-disk and limb behaviour of CME Link with coronographic observationsPerspective :systematic studies using the survey
CMEs, origin of energetic electron events…
LimitationsNeed of high dynamic range Hardly difficult to observe both weak and strong emissionPresently No sufficient frequency coverage
NEED for FASR
Narrow band horizontal features (Reiner et al;, 2000)
DATA ANALYSISCoronal and IP Radio signatures
Wide spectral coverage
Radio source (dm-m)
5 /11events: complex evolution (spectral, spatial and temporal)
WIND
DAM
NRH
18 February 2000
09:28
Radio signatures and CME
+ DAM NRH: 09:19 UT
Source of electrons in region of interaction,First shock is the triggering agentImportance of the wide spectral range (Klassen, 01)
Role of Moreton wave in flare/CME development
• Moreton wave and coronal m-type II burst
• Subsequent B interaction
Observations: agreement with P.F. Chen et al. (2002)Piston-driven shock along envelope of CMELegs Moreton waveMoving wave-like (enhanced plasma region ahead) EIT wave
succesive opening of B (Delannée et al., 99)
Role of Moreton wave in flare/CME development
Flare/CME events involving multi-magnetic structuresFull expansion < 10 min.
Moreton waves: causal association with CMEs : lateral expansion
BUT NOT ALWAYS Maia et al., 1999; Maia et al, 2001
Moreton waves and Flare/CME events
AD
C E
F
Complex of activity
Filament eruption
Moreton wave, 1400 km/s
Cospatialsouth loops
East and WestQuasi simultaneous
Moreton waves and Flare/CME events
South part of the CME: Breakout type instability
Null point 26OOO km, B reconnection, MHD wave triggers activity. S Loops pushing up and interconnecting with multiple B systems.North part of the CME (F sources):Null points western part 6000kmAlternatively, shock but no evidence in the north partMoreton wave and eruptive prominence no significant role
October 14 1999
Maia, Aulanier, S. J. Wang et al., 2002
Radio event
•Faint type III-like bursts above the parasitic polarity: beginning of the eruption in EIT (slow evolution phase).•Radio depression to appear ~40 mn later (acceleration phase)•Dynamical continuity between radio depression and CME substructures.
AD
C E
F
Cospatialsouth loops
East and WestQuasi simultaneous
South part of the CME: Breakout type instability Null point 26OOO km, B reconnection, MHD wave triggers activity. S Loops pushing up and interconnecting with multiple B systems.
North part of the CME (F sources):Null points western part 6000km
15 April 2001
Dynamics of CMEs: Detection of weak NT emissionsBastian et al., 2001: « Radio CME »(Maia et al., 2001 Plasma front , CME-Driven shock
Moreton waves and flare/CME events• Moreton wave• Pohjolainen, Maia, Pick, Vilmer
et al., 2001
Disk event
• (Bastian et al.,2001)
CME Radio imaging
CME-Driven shockPlasma front (Maia et al., 2001
Detection of weak emissions
eruptive scenario (non thermal/thermal emission), observational continuity between eruptive site and coronagraph f.o.v.
Feb 28th 2002
• Low energetical release event: ~B4 GOES event, faint type III like bursts.• Dark sigmoïd structure for the initial eruptive filament.•Eruption is triggered by the birth of a small parasitic polarity, a few hours before the D.B.
Ref: Marqué, Lantos, Delaboudinière, A&A, 2002, 387,317