Collisional Relaxation of an Ion-Electron Plasma in a Strong Magnetic Field

by Snir Cohen

Bgu
at Astrophysics and Cosmology Seminar

Wed, 03 Apr 2019, 11:10
Sacta-Rashi Building for Physics (54), room 207

Abstract

Collisional relaxation processes in plasmas has been studied extensively under various conditions. However, when a background magnetic field is presented, the analysis gets substantially harder since a closed form solution of the equations of motion does not exist for arbitrarily strong magnetic fields. Accordingly, when the gyromotion of the particles is taken into account, there is a need for further study.
The case of a strong (but finite) magnetic field is particularly relevant in antihydrogen experiments. In the ALPHA experiment (CERN), antiproton and positron plasmas are first held and later mixed together under ~1 T background fields. Due to the shallow potential well, only the slowest antiatoms are captured, so it is of highly importance to learn about the cooling/heating processes these plasmas undergo while they mix.
I will present a model of binary collisions for the interaction between a gyrating ion and a plasma electron and solve the equations of motion using perturbation theory. From the velocity transfers in the parallel and perpendicular directions relative to the magnetic field, the diffusion coefficients will be constructed. Then, in the framework of the kinetic theory in the diffusion approximation, the ion temperature relaxation times and the energy loss of a test ion in an electron plasma will be obtained.

Created on 30-03-2019 by Zitrin, Adi (zitrin)
Updaded on 30-03-2019 by Zitrin, Adi (zitrin)