Electrostatic Wave Observation during a Space Simulation Beam-Plasma-Discharge.
Abstract
In continuing the investigation of a series of space simulation experiments in the large vacuum chamber at the Johnson Space Center, the authors have analyzed observed extremely low frequency waves through associated measurements of electron density, electron temperature, plasma potential, power spectral density, and cross-correlation spectra. The experimental condition was that of a Beam-Plasma-Discharge with an electron gun voltage of 1.6 keV and a beam current of 40 ma in an external magnetic field of 1.5 gauss. Phase delays (obtained from cross-correlation measurements of density fluctuations) along with the measurements of plasma potential and frequency as a function of radius have been used to compare results to a zero-order slab model of non-local azimuthal drift wave propagation. Based on the results of plasma potential measurements, the laboratory rotational velocities obtained from frequency observations have been corrected for E X B Doppler shift to compare with theory in the plasma frame. In particular the inferred wave phase velocity in the plasma frame is found to be near one-half the electron diamagnetic drift velocity based on observations and the equilibrium drift correction. Although the authors' measurements do no uniquely define a propagation mode, they discuss a model of azimuthal drift wave propagation which is consistent with their observations. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 19, 1984
- Accession Number
- ADA147480
Entities
People
- D. N. Walker
- Edward P. Szuszczewicz
Organizations
- United States Naval Research Laboratory