
Accession Number : ADP006513
Title : Plasma Density Enhancements Created by the Ionization of the Earth's Upper Atmosphere by Artificial Electron Beams,
Corporate Author : STANFORD UNIV CA SPACE TELECOMMUNICATIONS AND RADIOSCIENCE LAB
Personal Author(s) : Neubert, Torsten ; Banks, Peter M.
Report Date : OCT 1990
Pagination or Media Count : 6
Abstract : Abstract. We present analytical calculations and experimental observations relating to the interaction with the Earth's upper atmosphere of electron beams emitted from low altitude spacecraft. The problem is described by two coupled nonlinear differential equations in the upgoing (along a magnetic field line) and downgoing differential energy flux. The equations are solved numerically, using the MSIS atmospheric model and the IRI ionospheric model. The results from the model compare well with recent observations from the CHARGE 2 sounding rocket experiment. Two aspects of the beamneutral atmosphere interaction are discussed: First we investigate the limits on the electron beam current that can be emitted from a space. craft without substantial spacecraft charging. This question is important because the charging of the spacecraft to positive potentials limits the current and the escape energy of the beam electrons and thereby limits the ionization of the neutral atmosphere. As an example we find from CHARGE 2 observations and from the model calculations that below about 180 km, secondary electrons generated through the ionization of the neutral atmosphere by 110 keV electron beams from sounding rockets, completely balance the beam current, thereby allowing the emission of very high beam currents, Second, the amount of plasma production in the beamstreak is discussed. Results are shown for selected values of the beam energy, spacecraft velocity, and spacecraft altitude.
Descriptors : *PLASMAS(PHYSICS), *IONOSPHERIC DISTURBANCES, ALTITUDE, ATMOSPHERES, ATMOSPHERICS, BALANCE, ELECTRON BEAMS, EMISSION, INTERACTIONS, IONIZATION, IONOSPHERIC MODELS, LINEAR DIFFERENTIAL EQUATIONS, LOW ALTITUDE, MAGNETIC FIELDS, MODELS, NEUTRAL, PRODUCTION, SECONDARY, SOUNDING ROCKETS, SPACECRAFT, SPACECRAFT CHARGING, UPPER ATMOSPHERE, VALUE, VELOCITY, ION DENSITY, ELECTRON ENERGY, IONIZATION.
Subject Categories : Atmospheric Physics
Distribution Statement : APPROVED FOR PUBLIC RELEASE