Accession Number:

AD0765927

Title:

Evaluation of an Orifice Probe for Plasma Diagnostics,

Descriptive Note:

Corporate Author:

YORK UNIV TORONTO (ONTARIO) CENTRE FOR RESEARCH IN EXPERIMENTAL SPACE SCIENCE

Report Date:

1972-09-01

Pagination or Media Count:

9.0

Abstract:

An orifice probe is described which permits determination of bulk plasma parameters, including temperatures, number densities and space potential, and which also permits simultaneous use of a mass spectrometer sampling through the same orifice. This probe combines a small, sharp-edged orifice located in a conducting wall with a planar internal geometry which is amenable to calculation. A detailed current-collection theory for a collisionless plasma is described. Experimental orifice probe characteristics are analysed for low-pressure RF plasmas in argon operating at 90 MHz with power levels of less than 60 W. The effects of secondary electron emission, electron reflection, field penetration, plasma inhomogeneities, and collisions in the sheath are examined. The electron and ion saturation regions and the electron-retarding region of the characteristics are found to indicate the properties of the bulk plasma. Modified author abstract

Subject Categories:

  • Plasma Physics and Magnetohydrodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE