QUASI-LINEAR THEORY OF COLLISIONLESS ELECTRON HEATING IN RADIO-FREQUENCY GAS-DISCHARGES

On the basis of quasilinear kinetic theory,. the. electron heating,of rf discharges is treated for characteristic scale lengths of the heati ng field much shorter than the electron mean free path. The analysis c onsiders plasmas bounded by walls providing specular reflection, The e xpressions for the coefficients of electron diffusion in energy space are obtained and analyzed for inductively and capacitively coupled pla smas. Accounting for the oscillatory spatial structure of the penetrat ing electric field in the regime of anomalous skin effect leads to a d ecrease of the diffusion coefficient for high, and an increase for low , energy electrons, It is shown that the presence of a second boundary in the case of collisionless plasma slabs results in a similar effect . The formation of energy distribution functions in various regimes of collisionless heating is discussed. The diffusion coefficients are pr esented taking into account ambipolar electric fields. (C) 1997 Americ an Institute of Physics.