8-12 August 2016
Novosibirsk
Asia/Novosibirsk timezone

Periodical plasma structures controlled by oblique magnetic field

11 Aug 2016, 11:20
20m
Novosibirsk

Novosibirsk

Board: 55
Oral Plasma-wall interaction Plasma-wall interaction

Speaker

Dr Irina Schweigert (ITAM SB RAS)

Description

A series of stationary two-dimensional (both parallel and transverse to the magnetic field) weak double layers with three, four, or more potential steps has been observed in a laboratory experiment in magnetized plasma in Ref. [1]. In this work, we present the results of kinetic and experimental study of the effect of magnetic field configuration on the nonthermal plasma ($T_i$=0.1 eV, $T_e$=1-10 eV) at low gas pressure (P=0.1 mTorr) bounded by cylindrical chamber. The periodical plasma structures with peaked plasma density were found both in 2D Particle in cell Monte Carlo collision (PIC MCC) simulations and in the experiment for the condition when the electron Larmor radius is comparable to the Debye length. We calculated the electron and ion densities, charge distributions, electrical potential distribution and etc for different angles between magnetic field and wall. We solved the system of equations which includes Boltzmann equations for electron and ion distribution functions (with elastic and inelastic collisions) and Poisson equation for the electric potential distribution. The calculations were performed with PlasmaNov code developed by Schweigert V. A. and Schweigert I. V. (see, for example [2]) with PIC MCC method. The intense electrical current was found to flow along the magnetic field lines in narrow periodical channels. The multiple weak double layers (electrical potential steps) were associated with the peaked plasma (charge) distribution. The transverse spatial size scales of the periodical plasma structure depend on the oblique magnetic field magnitude (B $<$ 200G), magnetic field angle relative to the axis of symmetry of the chamber and mean electron energy. 1. T. Intrator, J. Menard, and N. Hershkowitz, Multiple magnetized double layers in the laboratory Physics of Fluids B 5, 806 (1993); doi: 10.1063/1.860933 2. I.V. Schweigert, S.J. Langendorf, M. L. R. Walker, M. Keidar, Sheath structure transition controlled by secondary electron emission. Plasma Sources Sci. Technol. 24 (2) (2015) 025012

Primary author

Dr Irina Schweigert (ITAM SB RAS)

Co-authors

Dr Joseph Lukas (GWU, Washington, USA) Dr Michael Keidar (GWU, Washington, USA)

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