Debye-Onsager-Relaxation-Effect beyond linear Response and Antiscreening in Plasma Systems

The quantum kinetic equation for charged particles in strong electric fields is derived and analyzed with respect to the particle flux. It is found that the applied electric field is screened nonlinearly. The relaxation field is calculated completely quantum mechanically and up to any order in the applied field. The classical limit is given in analytical form. In the range of weak fields the deformation of the screening cloud is responsible for the Debye-Onsager relaxation effect. The result beyond linear response presented here allows to investigate a field regime where no screening cloud is present. The descreening field is determined as a function of thermal energy density of the plasma. For stronger fields the moving charge is accelerated by accumulated opposite charges in front of the particle. This can be understood in analogue to the accoustic Doppler effect. A critical field strength is presented up to which value a thermalized plasma is possible. The range of applicability of the treatment is discussed with respect to applied field strength and space gradients.