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Solar Origin of energetic particle events Near-relativistic impulsive electron events observed at 1 AU M. Pick, D. Maia, S.J. Wang, A. Lecacheux, D. Haggery, S. E. Hawkins COSPAR 2002
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CONTEXT Association with radio type III bursts (Lin, 1981) In-situ observations IP type III 2-20 KeV Above 25-50 keV Release often delayed up to 30 min Krucker et al., 1999: ¾ delayed events associated EIT wave without radio signature 2classes Role of the moving wave front? Triggering or acceleration? Haggerty et al.: 2001 Acceleration by CME driven shock and injection at about 1Rs Coronal sites of acceleration Magnetic restructuring during CME development ( Buttighoffer et al. 1996 Maia et al., 1999, 2001; Pojholainen et al., 2001: Klein et al., 2001)
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DATA ANALYSIS EPAM/ACE 38-315 keV (Haggerty and Roelof, 2001) 18 February 2002 Pitch angle distribution strongly collimated along IMF At Sun: Intensity maxima no dispersed, scatter- free propagation
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DATA ANALYSIS Coronal 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
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Radio signatures and CME + DAM NRH: 09:19 UT Source of electrons in region of interaction, First shock is the triggering agent ( 1400 km/s) Importance of the wide spectral range (Klassen, 01) V=898 (± 18) km/s t1Rs =09:06 ± 3min UT
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May 31, 1999 Coronal and IP Radio signatures Source of electrons associated with long duration stationary storm in corona. Vicinity of one CME leg (Kerdraon et al., 1983). Access to IP medium Electrons produced during magnetic reconnection during newly formed streamers? (Kahler and Hundhausen, 1992)
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May 01, 2000 is not a CME event Electrons Radio ejecta 1470 km/s V=1335 ± 70 km/s
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CONCLUSIONS Radio signatures found for the 5 « delayed events » Source of quasi-relativistic electrons associated with reconfiguration of coronal magnetic field during flare/CME events Present study suggests two kinds with distinct radio signatures Interaction with some triggering disturbance ( coronal wave, bow shock,….) Consistency with Krucker et al., 1999 Magnetic reconfiguration (post event, long duration). Evidence that electrons escape Altitude of this region highly variable from one event to the other one Opening of the magnetic field during CME development Importance of wide spectral and imaging coverage
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Energetic electron beam events November 28 1997 WIND/WAVES NRH E-W plot Three similar radio events located on the western limb. Each event includes two successive type III groups separated by 4 or 5 minutes D. Maia, M. Pick, S. E. Hawkins, S. Krucker, The Astrophys., 500, 1058, 2001
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Electron injection 04 April 2000
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Near-relativistic solar electron events ACE/EPAM 13:46:32 UT ( - 13.7 min propagation + 500s) Signature Ejecta radio 13:40 UT 750 km/s Near relativistic electrons Injection at 0.42 RS (~15 min delay if onset of EM radiation, no estimate of V shock)
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Near-relativistic solar electron events ACE/EPAM 10:23:55 UT ( - 13.7 min propagation + 500s) Signature Ejecta radio 10:21:30 UT 1470 km/s Near relativistic electrons Injection at 0.3 RS 1470 km/S
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