Stochastic acceleration of solar flare protons.
Abstract
The acceleration of solar flare protons by the cyclotron damping of intense Alfven wave turbulence in a magnetic trap is considered. The energy diffusion coefficient is computed for a nearisotropic distribution of superAlfvenic protons, and a steadystate solution for the particle spectrum is found for both transittime and diffusive losses out of the ends of the trap. The acceleration time to a characteristic energy of about 20 MeV per nucleon can be as short as 10 sec. On the basis of phenomenological arguments, it is inferred that the Alfven wave spectrum typically has an inverse square frequency dependence and that the correlation time of the turbulence lies in the range between 0.5 and 50 msec.
 Publication:

The Astrophysical Journal
 Pub Date:
 October 1979
 DOI:
 10.1086/157399
 Bibcode:
 1979ApJ...233..383B
 Keywords:

 Magnetohydrodynamic Waves;
 Particle Acceleration;
 Solar Flares;
 Solar Protons;
 Boundary Value Problems;
 Diffusion Coefficient;
 Magnetohydrodynamics;
 Mathematical Models;
 Nucleons;
 Transit Time;
 Solar Physics;
 Solar Flares:Protons