Hydromagnetic waves and cosmic ray diffusion theoryPitch angle diffusion of cosmic rays in hydromagnetic wave fields is considered strictly within the quasilinear approximation. It is shown that the popular assumption of an isotropic power spectrum tensor of magnetic fluctuations requires in this case equal forms and magnitudes of Alfven and magnetosonic wave spectra - a situation which is generally unlikely. The relative contributions to the pitch angle diffusion coefficient from the cyclotron resonances and Landau resonance due to the different types of waves are evaluated for a typical situation in the solar wind. Since in this approximation also the Landau resonance does not lead to particle reflections a proper consideration of the nonlinear particle orbits is indeed necessary to overcome the well known difficulties of quasilinear scattering theory for cosmic rays near 90 degrees pitch angle.
Document ID
19760043933
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Lee, M. A. (McDonnell Center for the Space Sciences; Washington University St. Louis, Mo., United States)
Voelk, H. J. (Max-Planck-Institut fuer Kernphysik Heidelberg, Germany)