The Seed Population for Energetic Particles Accelerated by CME-Driven Shocks |
| |
Authors: | M I Desai G M Mason J E Mazur J R Dwyer |
| |
Institution: | (1) Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238-5166, USA;(2) Applied Physics Laboratory, Johns Hopkins University, Johns Hopkins Road, Laurel, MD 20723-6099, USA;(3) The Aerospace Corporation, Space Sciences Department-Chantilly, 15049 Conference Center Drive, CH3/210 Chantilly, VA 20151, USA;(4) Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901-6975, USA |
| |
Abstract: | Understanding properties of solar energetic particle (SEP) events associated with coronal mass ejections has been identified
as a key problem in solar-terrestrial physics. Although recent CME shock acceleration models are highly promising, detailed
agreement between theoretical predictions and observations has remained elusive. Recent observations from ACE have shown substantial
enrichments in the abundances of 3He and He+ ions which are extremely rare in the thermal solar wind plasma. Consequently, these ions act as tracers of their source material,
i.e.,
3He ions are flare suprathermals and He+ ions are interstellar pickup ions. The average heavy ion composition also exhibits unsystematic differences when compared
with the solar wind values, but correlates significantly with the ambient suprathermal material abundances. Taken together
these results provide compelling evidence that CME-driven shocks draw their source material from the ubiquitous but largely
unexplored suprathermal tail rather than from the more abundant solar wind peak. However, the suprathermal energy regime has
many more contributors and exhibits much larger variability than the solar wind, and as such needs to be investigated more
thoroughly. Answers to fundamental new questions regarding the preferred injection of the suprathermal ions, the spatial and
temporal dependence of the various sources, and the causes of their variability and their effects on the SEP properties are
needed to improve agreement between the simulations and observations. |
| |
Keywords: | Sun: energetic particles Sun: coronal mass ejections Sun: flares |
本文献已被 SpringerLink 等数据库收录! |
|