Enrichment of suprathermal 3He++ associated with interplanetary coronal mass ejection events
Abstract
Three types of suprathermal helium are identified by the CELIAS/(H)STOF mass spectrometer onboard SOHO: 1) solar wind 4He++, 2) 4He+ pick-up ions, and 3) 3He from impulsive flares (Bamert et al, 2003, Kallenbach et al., 2003). In this work we analyze the spectra of the He isotopes, and their ratio in the energy range 0.035--2 MeV/amu associated with coronal mass ejection events. We study the fractionation during propagation in interplanetary space, and during injection and acceleration at coronal mass ejection driven shocks. The 3He/4He ratio strongly depends on the energy per mass. It varies from 0.01 at 50 keV/amu to almost 1 above 600 keV/amu. The 3He spectrum matches a model on stochastic acceleration in electron firehose waves in the source plasma of impulsive flares (Paesold et al., 2002) and subsequent transport through interplanetary space.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2003
- Bibcode:
- 2003AGUFMSH11D1146B
- Keywords:
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- 2111 Ejecta;
- driver gases;
- and magnetic clouds;
- 2118 Energetic particles;
- solar;
- 2139 Interplanetary shocks