Consequences of using nonlinear particle trajectories to compute spatial diffusion coefficients

Technical Report · Wed Sep 01 04:00:00 EDT 1976

OSTI ID:7223000

Goldstein, M L

The propagation of charged particles through interstellar and interplanetary space has often been described as a random process in which the particles are scattered by ambient electromagnetic turbulence. In general, this changes both the magnitude and direction of the particles' momentum. Some situations for which scattering in direction (pitch angle) is of primary interest were studied. A perturbed orbit, resonant scattering theory for pitch-angle diffusion in magnetostatic turbulence was slightly generalized and then utilized to compute the diffusion coefficient for spatial propagation parallel to the mean magnetic field, kappa. All divergences inherent in the quasilinear formalism when the power spectrum of the fluctuation field falls off as K to the minus Q power (Q less than 2) were removed. Various methods of computing kappa were compared, and limits on the validity of the theory, discussed. For Q less than 1 or 2, the various methods give roughly comparable values of kappa, but use of perturbed orbits systematically results in a somewhat smaller kappa than can be obtained from quasilinear theory. (auth)

• Research Organization: National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center
• OSTI ID: 7223000
• Report Number(s): N-76-32087; NASA-TM-X-71188; X-692-76-200
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
640107 -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHARGED PARTICLES
COSMIC RAY PROPAGATION
INTERPLANETARY SPACE
INTERSTELLAR SPACE
NONLINEAR PROBLEMS
SCATTERING
SPACE
TRAJECTORIES