Nonlocal effects in a bounded afterglow plasma with fast electrons

Abstract

Effects connected with nonlocality of the electron energy distribution function (EEDF) in a bounded, afterglow plasma with fast electrons can lead to a significant (many times of Te/e) increase in the near-wall potential drop, even if the density of this fast group is only a small fraction of the total electron density. This can substantially change the near-wall sheath thickness and electric field. Nonlocal fast electrons which are partially trapped in the plasma volume can increase the rate of stepwise excitation, supply additional heating to slow electrons and reduce their diffusion cooling rate. Altering the source terms of these fast electrons, to change their production rate will, therefore, alter the near-wall sheath and, through modification of the EEDF, a number of plasma parameters. Another possibility of modifying the EEDF is by application of a negative potential to a portion of the plasma boundary. This can allow modification of the fast part of the EEDF. The above effects and methods can be used in various research and technical applications