Self-limitation of Stably-trapped Particle Fluxes in Planetary Magnetospheres
Abstract
The Kennel-Petschek concept of self-limitation of stably-trapped particle fluxes in a planetary magnetosphere is re-examined. In contrast to the original Kennel-Petschek formulation,we carry out a fully relativistic analysis. Further,we replace the wave reflection criterion in the Kennel-Petschek theory by the condition that the limit on the stably-trapped particle flux is attained in the steady-state condition of marginal stability when electromagnetic waves generated at the magnetic equator acquire a specified gain over a given convective growth length. We derive relativistic formulae for the limiting electron integral and differential fluxes for a general planetary radaiation belt. The formulae depend explicitly on the spectral index and pitch-angle index of the assumed particle distribution,and on the ratio of the electron gyrofrequency to the electron plasma frequency. We compare the theoretical limits on the trapped flux with observed energetic electron fluxes at the Earth,and also at Jupiter and Uranus.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFMSM23A1573T
- Keywords:
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- 2716 MAGNETOSPHERIC PHYSICS / Energetic particles: precipitating;
- 2720 MAGNETOSPHERIC PHYSICS / Energetic particles: trapped;
- 2730 MAGNETOSPHERIC PHYSICS / Magnetosphere: inner;
- 2774 MAGNETOSPHERIC PHYSICS / Radiation belts