A kinetic model of transient effects in tokamak edge plasmas

Fluid descriptions are not adequate for edge plasma studies when the high collision frequency assumption fails in the presence of rapid transient processes. The results of analytic and numerical modeling of some of the non-Maxwellian features of edge plasma transport associated with transient heating and cooling phenomena in the scrape-off layer are presented, It is found that kinetic effects alter the heat conduction coefficient and lead to interesting critical behavior of the distribution function. The numerics are performed with the recently developed time-dependent Fokker-Planck code ALLA. (C) 1996 American Institute of Physics.