EVALUATION OF THE REAL SPACE ELECTRON DRIFT VELOCITY IN GASES USING MOMENT EQUATIONS PERFORMED IN VELOCITY SPACE

摘要

The centroid drift velocity W-r and the mean electron velocity W-v of electron swarms in gases have different values even under the same electric field when electron-impact ionization and/or electron attachment processes are present. A new evaluation technique for W-r is proposed based on moment equations, in which the quantitative difference between W-r and W-v is described as a function defined in velocity space. W-r values are derived from calculations using a propagator method performed in velocity space without the electron distribution in real space. The effects of ionization and attachment on W-r are quantitatively analysed for F-2 and SF6, and the mechanism producing the difference between W-r and W-v is illustrated. [References: 17]