Accession Number : AD0718412

Title :   The Effects of Spatial Nonuniformities on High-Temperature Microwave Breakdown.

Descriptive Note : Rept. for Aug 69-Jun 70,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Light,Glenn C.

Report Date : 02 FEB 1971

Pagination or Media Count : 40

Abstract : Microwave breakdown over an X-Band waveguide aperture in a ground plane is studied experimentally and theoretically. Experimental data are presented for cw and pulsed breakdown in air and in nitrogen. Calculations based on recent analyses for the effects of nonuniformities on breakdown are made for this geometry and results are compared with experimental data. Calculations of breakdown are compared using first, the classical phenomenological data set for the fundamental breakdown parameters and second, recently reported values for these parameters from a numerical integration of the Boltzman equation with cross sections for air. The effects of the unsteady laminar compressible boundary layer on breakdown in recent shock tube experiments are evaluated. Calculations are made for breakdown in typical conical reentry vehicle boundary layers including the effects of boundary layer and electric field nonuniformities; results are compared for various simplifying assumptions. The major conclusions are that recent theories for the effects of nonuniformities on breakdown are entirely adequate and that the effects of boundary layers in recent shock tube breakdown experiments were generally negligible. (Author)

Descriptors :   (*PLASMA MEDIUM, MICROWAVES), (*ATMOSPHERE ENTRY, BLACKOUT(PROPAGATION)), BOUNDARY LAYER, ELECTRON DENSITY, IONIZATION, ANTENNAS, ELECTRIC FIELDS, TRANSPORT PROPERTIES, DIFFERENTIAL EQUATIONS, X BAND

Subject Categories : Plasma Physics and Magnetohydrodynamics
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE