Quasilinear waveparticle interactions in the earth's radiation belts
Abstract
A selfconsistent theory on the interaction of magnetospheric particles with ducted electromagnetic cyclotron waves is presented. The main contribution is to calculate the coupling coefficients for the ray equations describing the temporal evolution of the cyclotron instability. These are obtained within the framework of quasilinear interaction of waves and particles. A set of equations is derived based on the FokkerPlanck theory of pitch angle diffusion, describing the evolution time of the number of particles in the flux tube and the energy density of waves for the interaction of Alfven waves with protons and of whistler waves with electrons. The coupling coefficients are obtained, based on a quasilinear analysis after averaging over the particle bounce motion. It is found that the equilibrium solutions for particle fluxes and wave amplitudes are stable under small local perturbations. The reflection of the waves in the ionosphere is discussed. A stability analysis around the equilibrium solutions for precipitating particle fluxes and wave intensity indicates that an actively excited ionosphere can cause the development of explosive instabilities.
 Publication:

Journal of Geophysical Research
 Pub Date:
 November 1989
 DOI:
 10.1029/JA094iA11p15243
 Bibcode:
 1989JGR....9415243V
 Keywords:

 Magnetohydrodynamic Stability;
 Magnetohydrodynamic Waves;
 Particle Interactions;
 Radiation Belts;
 Terrestrial Radiation;
 Wave Interaction;
 Cyclotron Frequency;
 Earth Ionosphere;
 Electrons;
 FokkerPlanck Equation;
 Protons;
 Wave Reflection;
 Space Radiation