Accession Number : ADA130116

Title :   Electron Beam-Induced Electromagnetic Waves in a Magnetospheric Plasma.

Descriptive Note : Technical rept.,


Personal Author(s) : Donatelli,D E ; Chang,T S

PDF Url : ADA130116

Report Date : 15 May 1983

Pagination or Media Count : 22

Abstract : A theoretical interpretation of waves detected by the SCATHA satellite near geostationary altitude during electron beam operations is presented. The observations consist of emission bands at or between harmonics of the electron gyrofrequency, combining background and beam-induced emissions. Beam-induced emissions often broaden and/or intensify the emission band. A magnetic field component is detected along with the electric field component for most of the emissions. Therefore, these emissions are assumed to be electromagnetic waves. The linearized Vlasov equation is used to derive the dispersion relation for electromagnetic waves in a warm, homogeneous, uniformly magnetized plasma. The ambient plasma is represented as a Maxwellian distribution and the electrom beam as a delta-function in velocity space. The dispersion relations is solved analytically for non-resonant, perpendicularly propagating, electromagnetic waves. Using observational data to quantitatively define the plasma parameters, unstable solutions are found at frequencies consistent with those of the observed emissions. (Author)

Descriptors :   *Electron beams, *Electromagnetic wave propagation, *Plasmas(Physics), *Magnetosphere, *Wave propagation, Emission spectra, Frequency bands, Gyroscopes, Magnetic fields, Electric fields, Detection, Spacecraft, Wave propagation

Subject Categories : Electricity and Magnetism
      Particle Accelerators
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE