Solar energetic particles: Shock acceleration and transport through self-amplified waves
Abstract
This article reviews our work on the powerful influence of self-amplified Alfvén waves on the interplanetary (IP) transport and shock acceleration of solar energetic particles (SEPs). In large gradual events, a huge number of shock-accelerated protons stream through the IPmediumand amplify ambient Alfvén waves by orders of magnitude. Nonlinear models that take account of selfamplified waves semi-quantitatively explain many intriguing SEP observations at 1 AU: (a) upper limits to early SEP intensities, (b) flat intensity energy spectra up to ~ 30 MeV/amu before shock arrival, and (c) complex temporal, energy, and event-to-event variations of elemental abundances. Streaming limit complicates estimation of the number and energy of SEPs accelerated in a solar event but provides a safety window for astronauts to seek shelter before a potential hazardous intensity rise at shock passage. Self-amplified waves help bootstrap shock acceleration and the high near-shock SEP intensity predicted at <= 20rsolar. is relevant to inner heliospheric space missions.
- Publication:
-
Physics of the Heliosphere: A 10 Year Retrospective
- Pub Date:
- May 2012
- DOI:
- 10.1063/1.4723610
- Bibcode:
- 2012AIPC.1436..212N
- Keywords:
-
- element relative abundance;
- interplanetary matter;
- magnetohydrodynamic waves;
- shock waves;
- solar radiation;
- solar spectra;
- solar wind;
- 96.50.Fm;
- 96.50.Tf;
- 96.60.Tf;
- 96.60.Vg;
- Planetary bow shocks;
- interplanetary shocks;
- MHD waves;
- plasma waves turbulence;
- Solar electromagnetic emission;
- Particle emission solar wind