Interplanetary transport of solar electrons and protons: Effect of dissipative processes in the magnetic field power spectrum
Abstract
Quasilinear theory describing charged particle transport in interplanetary space within the framework of a slab turbulence picture was for a long time confronted with the problem that the theoretically predicted mean free path for scattering at magnetic field fluctuations was too small when compared with the corresponding parameter derived from fits to observed intensity and anisotropy profiles of solar energetic particles. The theory up to now has neglected the dispersiveness of some of the scattering plasma waves and the effects resulting from the finite temperature of the plasma through which the particles propagate. We have therefore attempted to give a more realistic model of an observed interplanetary turbulence spectrum. The most simple picture we find requires the dissipation range to be constituted by parallel dispersive whistler, electron and ion cyclotron waves in a warm plasma (β~1). The dispersion relation of heavily thermally affected ion cyclotron waves needed in this model is calculated for the first time. The model is fitted to the turbulence spectrum measured on June 7, 1980, by ISEE 3 (ICE). The derived model parameters are used in a quasilinear calculation of both proton and electron mean free paths. As a first step resonance broadening due to wave damping is neglected. The results are compared with typical empirical proton mean free paths and with electron mean free paths obtained from fits to electron intensity and anisotropy profiles observed simultaneously by the same satellite. In both cases the theoretical values seem to be systematically larger than the empirical ones. Thus scattering enhancements by nonlinear or thermal resonance broadening or oblique waves now bear the hope to remove the discrepancy between theory and observation.
 Publication:

Journal of Geophysical Research
 Pub Date:
 August 1993
 DOI:
 10.1029/93JA00450
 Bibcode:
 1993JGR....9813261A
 Keywords:

 Interplanetary Medium;
 Ion Cyclotron Radiation;
 Particle Motion;
 Solar Electrons;
 Solar Protons;
 Mathematical Models;
 Particle Trajectories;
 Wave Dispersion;
 Whistlers;
 Solar Physics;
 Interplanetary Physics: Cosmic rays;
 Interplanetary Physics: Plasma waves and turbulence;
 Space Plasma Physics: Transport processes;
 Space Plasma Physics: Wave/particle interactions