Kinetic plasma instabilities due to charge exchange and elastic collisions

15th Latin American Workshop on Plasma Physics; 21st IAEA TM on Research Using Small Fusion Devices

Horký, M.^1,2 ; Miloch, W.J.^3

Department of Physics, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague

166 27, Czech Republic^1

Astronomical Institute, Czech Academy of Sciences, Boní II 1401/1a, Prague

141 00, Czech Republic^2

Department of Physics, Univeristy of Oslo, P. O. Box 1048, Blindern, Oslo

N-0316, Norway^3

关键词: Charge exchange collision;    Collisional process;    Elastic collision;    Laboratory experiments;    Low frequency oscillations;    Particle-in-cell simulations;    Saturation levels;    Two stream instability;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/591/1/012034/pdf
DOI  :  10.1088/1742-6596/591/1/012034

来源: IOP

【 摘 要 】

With numerical particle-in-cell simulations, we study kinetic plasma instabilities induced by collisions between plasma particles and neutral background in magnetized drifting plasmas. We consider the role of charge exchange as well as elastic collisions in the evolution of the system. Charge exchange collisions can give rise to velocity distributions in the form of loss- cone or ring shaped distributions that can become linearly unstable. Elastic collisions also lead to the instability, but in this case the principal mechanism may be attributed to the generalized two-stream instability. We investigate the growth rates and saturation levels for instabilities associated with these collisional processes, and find higher saturation levels and stronger fluctuations for the case with charge exchange collisions. Characteristics of the studied system are similar to the E- and F-regions of the Earth's ionosphere. Our results are relevant for explaining some of the low frequency oscillations observed in the lower parts of the Earth's ionosphere, and are also relevant for some laboratory experiments.