Satellite particle exospheres of planets: Application to Earth
Abstract
Neutral planetary exospheres are built up by three different kinds of gas particles, namely ballistic, hyperbolic and elliptic particles. Elliptic particles have their origin exclusively in exospheric regions of the planet where they are fed into satellite orbits by different physical processes. It has been suggested that elliptic particles that do not enter the collisiondominated planetary gas regions represent an important fraction of the particles constituting the outer parts of planetary exospheres. Here we develop a theoretical concept for a rigorous calculation of elliptic particle distributions using Boltzmann equation kinetic approaches. Taking into account realistic gain and loss processes a general procedure for the determination of satellite particle densities for the terrestrial case is presented. We give representative height profiles of the satellite particle density in the exosphere for weak and strong solar activity. Our results are compared with those obtained by simplified theoretical approaches; pronounced deviations are obvious. It is shown that satellite particles are more relevant in low temperature exospheres leading to an orderofmagnitude difference above 1500 km between the densities for weak and strong solar activity. There is a general tendency for satellite particles to become increasingly important with increasing height.
 Publication:

Planetary and Space Science
 Pub Date:
 September 1979
 DOI:
 10.1016/00320633(79)901363
 Bibcode:
 1979P&SS...27.1163R
 Keywords:

 Elliptical Orbits;
 Exosphere;
 Natural Satellites;
 Particle Size Distribution;
 Particle Trajectories;
 Boltzmann Transport Equation;
 Density Distribution;
 Distribution Functions;
 Ion Density (Concentration);
 Ion Temperature;
 Lyman Alpha Radiation;
 Positive Ions;
 Solar Activity;
 Lunar and Planetary Exploration