Propagation of Galactic Cosmic Rays under Diffusive Reacceleration
Abstract
The propagation of cosmic rays in the galaxy is understood as a diffusive process where the magnetic field irregularities serve as scattering center. In this paper we pursue the idea that particles which interact with turbulent magnetic fields should naturally also gain energy due to a stochastic secondorder Fermi type of acceleration. This link between diffusion and reacceleration is based on general physical principles, and we can show that the cosmicray data can be explained in this 'Diffusive Reacceleration Model.' As a consequence, the escape length lambda_{esc}(E), which defines the particles path in the galaxy, becomes a powerlaw in rigidity with an exponent of 1/3, which would indicate a Kolmogorovtype spectrum of magnetic turbulences. The increase of lambda_{esc}(E) combined with the increase of the amount of reacceleration to low energies in then interpreted as a decrease of the diffusion coefficient or an increase of the frequencies of scattering center.
 Publication:

The Astrophysical Journal
 Pub Date:
 March 1995
 DOI:
 10.1086/175350
 Bibcode:
 1995ApJ...441..209H
 Keywords:

 Astronomical Models;
 Cosmic Rays;
 Diffusion;
 Particle Acceleration;
 Turbulence;
 Kolmogorov Theory;
 Magnetohydrodynamics;
 Mathematical Models;
 Radiative Transfer;
 Stochastic Processes;
 Transport Theory;
 Astrophysics;
 ACCELERATION OF PARTICLES;
 DIFFUSION;
 ISM: COSMIC RAYS;
 MAGNETOHYDRODYNAMICS: MHD;
 TURBULENCE