Shock Acceleration of Solar Energetic Protons: The First 10 Minutes
Abstract
Proton acceleration at a parallel coronal shock is modeled with self-consistent Alfvén wave excitation and shock transmission. 18-50 keV seed protons at 0.1% of plasma proton density are accelerated in 10 minutes to a power-law intensity spectrum rolling over at 300 MeV by a 2500 km s-1 shock traveling outward from 3.5 r⊙, for typical coronal conditions and low ambient wave intensities. Interaction of high-energy protons of large pitch angles with Alfvén waves amplified by low-energy protons of small pitch angles is key to rapid acceleration. Shock acceleration is not significantly retarded by sunward streaming protons interacting with downstream waves. There is no significant second-order Fermi acceleration.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2008
- DOI:
- 10.1086/592996
- Bibcode:
- 2008ApJ...686L.123N
- Keywords:
-
- acceleration of particles;
- shock waves;
- Sun: coronal mass ejections;
- Sun: particle emission