Jupiter's Radiation Belts.
Abstract
Close encounters of Pioneer 10 (December 1973) and Pioneer 11 (December 1974) with the planet Jupiter provided the first in situ observations of zenomagnetically trapped particle radiation. These observations have stimulated continuing theoretical efforts to understand the reported findings and to extrapolate from them to other planets and other epochs. The observed radiation belts seem to be populated by radial diffusion from an external source. The diffusion coefficient seems to be that derived from fluctuations in the polarization electric field produced by neutral winds in the Jovian ionosphere, which is coupled to the magnetosphere by equipotential B-field lines. Radiation-belt electrons lose energy and change their equatorial pitch angles by virture of synchrotron emission. Radiation-belt ions and electrons both may be subject to pitch-angel diffusion caused by waves that the respective particle anisotropies have created through plasma instabilities. Finally, radiation-belt ions and electrons seem to experience absorption by the inner Jovian satellites (moons) in a manner that may depend upon the species and energy of the incident radiation-belt particle. It is not yet known whether satellite-associated clouds of sodium and sulfur contribute substantially to the inferred particle absorption. Also still open is the question of whether the satellites provide a substantial source of radiation-belt particles.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 28, 1978
- Accession Number
- ADA063014
Entities
People
- Michael Schulz
Organizations
- The Aerospace Corporation