Bonn 2000 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
P: Plasmaphysik
P 22: Theorie (Poster)
P 22.7: Poster
Donnerstag, 6. April 2000, 17:00–19:30, Aula
Nonlinear energy loss of ions in magnetized electron plasmas — •G. Zwicknagel, M. Walter, C. Toepffer, and P.-G. Reinhard — Institut für Theoretische Physik, Universität Erlangen, Staudtstr. 7, 91058 Erlangen
The transport properties of a plasma in an external magnetic field still raises many questions. For example, the energy loss of highly charged, slow ions involves a nonlinear regime where perturbative treatments are not applicable. We investigated in detail this nonlinear energy loss for the case of nonmagnetized electron targets by using numerical simulations as an essential tool [1]. We briefly report on the major results of these studies like e.g. the dependence of the energy loss on the ion charge Z. This changes with increasing coupling strength from a scaling like Z2 to a Zx-behaviour with x ≈ 1.2 … 1.5. In a first step to extend this work to magnetized electron plasmas we concentrate on the relevant transport cross sections for binary ion–electron collisions in the presence of a homogeneous magnetic field. Here, in view of the nonlinear energy loss, special attention is paid to situations where a highly charged ion is moving in arbitrary directions with respect to the magnetic field while the relative ion-electron velocity is low. This requires a fully numerical evaluation of the desired cross sections which is done by calculating individual trajectories combined with a Monte-Carlo method for the integration over the possible initial conditions. The results of this approach will be presented and discussed.
[1] G. Zwicknagel, C. Toepffer and P.-G. Reinhard, Stopping of heavy ions in plasmas at strong coupling, Physics Reports 309 (1999) 117.