A perturbation approach to coherent propagation of energetic charged particles in random magnetic fields.
Abstract
The FokkerPlanck equation describing the propagation of charged particles in magnetic fields that consist of a dominant constant guiding field and superposed random fluctuations is solved by applying the perturbation method of dividing the total particle density into an averaged isotropic and a small anisotropic component. A particle transport equation is derived which describes the 'coherent' propagation of a particle pulse whose center moves at half the constant total particle velocity in either the positive or negative direction. The range of validity of the coherent solution is examined, and the general formulas for coherent propagation are applied to the slab, isotropic, and Alfvenwave models of magneticfield fluctuations. Ranges of magneticfluctuation spectral indices are identified over which diffusive and coherent particletransport modes can exist in the three models considered.
 Publication:

The Astrophysical Journal
 Pub Date:
 January 1977
 DOI:
 10.1086/154967
 Bibcode:
 1977ApJ...211..587K
 Keywords:

 Charged Particles;
 Cosmic Rays;
 Interplanetary Magnetic Fields;
 Magnetic Field Configurations;
 Particle Motion;
 Perturbation Theory;
 Astronomical Models;
 Coherent Radiation;
 FokkerPlanck Equation;
 Particle Density (Concentration);
 Particle Energy;
 Random Processes;
 Transport Properties;
 Space Radiation