Accession Number : ADP005700

Title :   Electron Beam Experiments at High Altitudes,

Corporate Author : ALABAMA UNIV IN HUNTSVILLE DEPT OF PHYSICS

Personal Author(s) : Olsen, R. C.

Report Date : MAY 1987

Pagination or Media Count : 8

Abstract : Experiments with the electron gun on the SCATHA satellite produced evidence of beam-plasma interactions, and heating of the low energy electrons around the satellite. These experiments were conducted near geosynchronous orbit, in the dusk, bulge, and plasma sheet, with one short operation in the lobe regions, providing a range of ambient plasma densities. The electron gun was operated at 50 eV, with beam currents of 1, 10 and 100 microAmps. Data from electrostatic analyzers and the DC electric field experiment show that the satellite charged to near the beam energy in sunlight, if the beam current was distribution functions which had peaks, or plateaus at energies greater than the satellite potential. These measurements indicate heating of the ambient plasma, at several Debye lengths from the satellite (several 10's of meters), with the heated plasma then accelerated into the satellite. It is likely that the 'ambient' plasma is in fact the photoelectron sheath generated by the satellite.

Descriptors :   *SYNCHRONOUS SATELLITES, *PLASMAS(PHYSICS), SCIENTIFIC SATELLITES, DENSITY, ELECTRON BEAMS, HEATING, INTERACTIONS, ELECTRON GUNS, PHOTOELECTRONS, PLASMA SHEATHS, SUNLIGHT, HIGH ALTITUDE, ELECTRIC CHARGE, ELECTROSTATIC ANALYZERS.

Subject Categories : Unmanned Spacecraft
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE