DIFFUSION TENSOR IN ELECTRON-TRANSPORT IN GASES IN A RADIOFREQUENCY FIELD

Electron transport theory in gases in a radio-frequency field is devel oped in the hydrodynamic regime from the density gradient expansion me thod of the Boltzmann equation. Swarm parameters for the radio-frequen cy (rf) field with periodic time modulation are derived as functions o f both reduced effective field strength and reduced angular frequency from the time dependent velocity distribution function. The rf electro n transport in phase space is analyzed from the series of governing eq uations by a direct numerical procedure (DNP). Electron velocity distr ibution function and corresponding swarm parameters obtained from DNP agree with those of the Monte Carlo simulation in the frequency range 10-200 MHz at 10 Td for Reid's inelastic ramp model gas. The temporal modulation of the ensemble average of energy and the diffusion tensor an discussed. The appearance of the anomalous time behavior of the lon gitudinal diffusion coefficient is discussed in particular detail, and we provide an explanation of the observed effect.