Solar Cycle Variations of Suprathermal Fe/O and He3/He4 Abundance Ratios Associated With CME-driven Interplanetary Shocks
Abstract
CME-driven interplanetary (IP) shocks are presently believed to accelerate material out of a complex and dynamic pool of suprathermal material that is apparently ubiquitous in the inner heliosphere under all types of solar activity conditions. We survey the elemental abundances of suprathermal (200 keV/nucleon) heavy ions from 3He through Fe associated with ~80 such CME-driven IP shocks observed by the Ultra-Low-Energy Isotope Spectrometer (ULEIS) on board the Advanced Composition Explorer (ACE) and by the SupraThermal-through-Energetic Particle (STEP) instrument on board the Wind spacecraft from October 1997 through June 2008. In particular, we examine the dependences of these abundances on the phase of the solar cycle. Finally, we discuss our results in terms of the origin of the suprathermal seed populations through the various phases of the solar cycle and their relationship with various shock acceleration mechanisms.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMSH23C..03A
- Keywords:
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- 2101 Coronal mass ejections (7513);
- 2114 Energetic particles (7514);
- 2139 Interplanetary shocks