Accession Number : ADA062703

Title :   Study of Electrostatic Probes in Nonequilibrium Plasmas.

Descriptive Note : Final rept. 1 Sep 73-31 Mar 75,


Personal Author(s) : Shkarofsky,I P ; Bonnier,A

PDF Url : ADA062703

Report Date : Jun 1975

Pagination or Media Count : 228

Abstract : The response of electrostatic probes (plane, sphere, and cylinder) in a nonequilibrium plasma, whose electron energy distribution function is neither Maxwellian nor isotropic, is studied with application to diagnostics of a lasing medium. First, the situation of a collisionless sheath is considered. The current-voltage characteristics of probes are derived, for given arbitrary variations for the first three Cartesian tensor components of the distribution function. The inverse problem is then solved, and analytical and numerical means to deduce these details of the distribution function from the currents are provided, based on using a plane probe whose orientation is varied. Next, the quasicollisional sheath is analyzed. We generalize the works of Swift and Lukovnikov and Novgorodov to include the anisotropic contribution from the distribution function. Finally, we use a hybrid moment approach to analyze the continuum regime. This approach uses our previous results to match properly (including anisotropic terms) at the boundary between the collisionless and collisional parts of the sheath and improves the works of Waymouth and Wilkins and Katra. (Author)

Descriptors :   *Plasma diagnostics, *Langmuir probes, Nonequilibrium flow, Anisotropy, Distribution functions, Plasma sheaths, Boltzmann equation

Subject Categories : Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE