Boltzmann Equation Analysis of Electron Swarm Development in Model Gases with Power-Law Elastic Scattering

概要

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The electron swarm behaviors in model gases with elastic momentum transfercross-section of the l'orm y(e)ccz' (r= - l /2, 0, 1 /2 and l) are analyzed by the timeof-flight method of a Boltzmann equation. The velocity distribution functions are ap-prroximated by three term expansion. Here e is the electron energy. The ratios D./D,are calculated to study an anisotropy in real space. Here D.. and D. are thelongitudinal and the transverse diffusion coefficients to an electric field E. The valuesof electron-to-atom mass ratios m/M are changed from 10 ' to 5 X 10 ' and thevalues of E/N are taken as 2.8, 14 and 28 Td respectively. Here N is the gas numberdensity. The present result shows that the anisotropy in real space depends uponm7M regardless of E/N. The discrepancy between the electron diffusion coefficientD. as defined in velocity space and D., and the validity of the usual two-term methodto calculate the time-of-flight parameters are discussed in detail.[Boltzmann equation, electron swarm, time-of-flight, anisotropy, diffusion ll coefficient, elastic cross-sectionl
社団法人日本物理学会の論文
1992-02-15