Accession Number : AD0733328

Title :   The Effect of Condensation on the Breakdown Strength of a Helium-Mercury Mixture,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DIV OF SPONSORED RESEARCH

Personal Author(s) : Fink,Daniel J.

Report Date : AUG 1971

Pagination or Media Count : 80

Abstract : The effect of condensation on the DC breakdown strength of a helium-mercury mixture (helium at a reference pressure of one atmosphere with up to ten percent by weight of mercury) was calculated. The breakdown condition was determined by considering the electron current produced by ion bombardment of the cathode. The first Townsend coefficient was used as the parameter to describe breakdown. The first Townsend coefficient was computed by taking moments of the electron distribution function. The distribution function was calculated using a first order expansion in spherical harmonics of the distribution function in Boltzman's equation. The resulting equation for the distribution function was solved using integral and differential equation techniques in an iterative scheme. It was found that the presence of drops increased the breakdown strength by up to 88% over that of helium (with the Penning effect) without drops. Also, an analytical form for the contribution of drops to the first Towsend coefficient and an analytical method of estimating the increase in breakdown strength are presented. (Author)

Descriptors :   (*GAS DISCHARGES, MIXTURES), (*PLASMA GENERATORS, ELECTRIC FIELDS), HELIUM, MERCURY, ELECTRODES, ION BOMBARDMENT, DISTRIBUTION FUNCTIONS, PARTIAL DIFFERENTIAL EQUATIONS, GAS IONIZATION, ELECTRIC POWER PRODUCTION, NUMERICAL ANALYSIS, COMPUTER PROGRAMS

Subject Categories : Electric Power Production and Distribution
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE