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Title: Numerical study on the stability of weakly collisional plasma in E×B fields

Abstract

Plasma stability in weakly collisional plasmas in the presence of E×B fields is studied with numerical simulations. Different types of ion-neutral collisions are considered in a fully magnetized regime. We study the influence of ion-neutral collisions and the role of collision types on the stability of plasma. It is found that the stability of plasma depends on the type of ion-neutral collisions, with the plasma being unstable for charge exchange collisions, and stable for the elastic scattering. The analysis focuses on the temporal evolution of the velocity phase space, RMS values of the potential fluctuations, and coherent structures in potential densities. For the unstable case, we observe growth and propagation of electrostatic waves. Simulations are performed with a three-dimensional electrostatic particle in cell code.

Authors:
 [1];  [2];  [3]
  1. Department of Physics, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, 166 27 Prague (Czech Republic)
  2. (Czech Republic)
  3. Department of Physics, University of Oslo, P.O. Box 1048 Blindern, N-0316 Oslo (Norway)
Publication Date:
OSTI Identifier:
22408062
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 2; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CHARGE EXCHANGE; COLLISIONAL PLASMA; COLLISIONS; COMPUTERIZED SIMULATION; ELASTIC SCATTERING; ELECTRIC FIELDS; MAGNETIC FIELDS; NUMERICAL ANALYSIS; PHASE SPACE; PLASMA INSTABILITY; PLASMA WAVES; THREE-DIMENSIONAL CALCULATIONS

Citation Formats

Horký, M., E-mail: miroslav.horky@fel.cvut.cz, Astronomical Institute, Czech Academy of Sciences, Boční II 1401/1a, 141 00 Prague, and Miloch, W. J. Numerical study on the stability of weakly collisional plasma in E×B fields. United States: N. p., 2015. Web. doi:10.1063/1.4906887.
Horký, M., E-mail: miroslav.horky@fel.cvut.cz, Astronomical Institute, Czech Academy of Sciences, Boční II 1401/1a, 141 00 Prague, & Miloch, W. J. Numerical study on the stability of weakly collisional plasma in E×B fields. United States. doi:10.1063/1.4906887.
Horký, M., E-mail: miroslav.horky@fel.cvut.cz, Astronomical Institute, Czech Academy of Sciences, Boční II 1401/1a, 141 00 Prague, and Miloch, W. J. Sun . "Numerical study on the stability of weakly collisional plasma in E×B fields". United States. doi:10.1063/1.4906887.
@article{osti_22408062,
title = {Numerical study on the stability of weakly collisional plasma in E×B fields},
author = {Horký, M., E-mail: miroslav.horky@fel.cvut.cz and Astronomical Institute, Czech Academy of Sciences, Boční II 1401/1a, 141 00 Prague and Miloch, W. J.},
abstractNote = {Plasma stability in weakly collisional plasmas in the presence of E×B fields is studied with numerical simulations. Different types of ion-neutral collisions are considered in a fully magnetized regime. We study the influence of ion-neutral collisions and the role of collision types on the stability of plasma. It is found that the stability of plasma depends on the type of ion-neutral collisions, with the plasma being unstable for charge exchange collisions, and stable for the elastic scattering. The analysis focuses on the temporal evolution of the velocity phase space, RMS values of the potential fluctuations, and coherent structures in potential densities. For the unstable case, we observe growth and propagation of electrostatic waves. Simulations are performed with a three-dimensional electrostatic particle in cell code.},
doi = {10.1063/1.4906887},
journal = {Physics of Plasmas},
number = 2,
volume = 22,
place = {United States},
year = {Sun Feb 15 00:00:00 EST 2015},
month = {Sun Feb 15 00:00:00 EST 2015}
}
  • It has been demonstrated that in the presence of weak collisions, described by the Lenard-Bernstein (LB) collision operator, the Landau-damped solutions become true eigenmodes of the system and constitute a complete set [C.-S. Ng et al., Phys. Rev. Lett. 83, 1974 (1999) and C. S. Ng et al., Phys. Rev. Lett. 96, 065002 (2004)]. We present numerical results from an Eulerian Vlasov code that incorporates the Lenard-Bernstein collision operator [A. Lenard and I. B. Bernstein, Phys. Rev. 112, 1456 (1958)]. The effect of collisions on the numerical recursion phenomenon seen in Vlasov codes is discussed. The code is benchmarked againstmore » exact linear eigenmode solutions in the presence of weak collisions, and a spectrum of Landau-damped solutions is determined within the limits of numerical resolution. Tests of the orthogonality and the completeness relation are presented.« less
  • Recently, Zawaideh {ital et} {ital al}. published a paper (Phys. Fluids B {bold 2}, 647 (1990)) asserting that they had obtained, from a more accurate set of fluid equations, physically reasonable plasma sheath solutions of an oscillating nature violating Bohm's criterion. In contrast to this statement, it is shown here that the violation of Bohm's criterion is based on an incorrect interpretation of the plasma sheath concept and that the oscillations are due to an incorrect initial condition in the calculations.
  • Electrostatic ion cyclotron wave fields are determined in a magnetized and weakly collisional plasma. A phased-locked Laser Induced Fluorescence (LIF) diagnostic is used to directly measure the wave perturbed ion velocity distribution. Comparing these local LIF measurements with a theoretical model uniquely determines the wave parameters, such as the wave potential, the three-dimensional wave vector, and the effective wave damping. The self-consistent wave{endash}particle interaction is modeled by Boltzmann{endash}Poisson equations in the limit of weak collisions. The wave parameters determined from local measurements agree with those determined from spatial scans. {copyright} {ital 1996 American Institute of Physics.}
  • The stability of weakly ionized and magnetized plasma in the presence of transverse (to the magnetic field) neutral wind is investigated in the present work. The collisional coupling of ambient background flow to the magnetized plasma gives rise to an electric field. In the presence of charged unmagnetized dust, electrostatic fluctuations in such plasma become unstable, with the growth rate dependent on the plasma thermal speed as well as on the dust charge and collision frequencies. This instability is similar to the Farley-Buneman instability. However, unlike Farley-Buneman, where the growth rate is directly dependent on the background flow, this dependencemore » in the present case is only indirect. It is shown that this instability can grow over few seconds in the Earth's lower ionosphere and thus could play an important role in the structure formation.« less
  • The low-frequency instability of a cylindrical poorly magnetized plasma with an inward-directed radial electric field is studied changing the gas pressure and the ion cyclotron frequency. The unstable frequency always decreases when the gas pressure is increased indicating collisional effects. At a fixed pressure, the unstable frequency increases with the magnetic field when the B-field is low and decreases at larger magnetic field strength. We find that the transition between these two regimes is obtained when the ion cyclotron frequency equals the ion-neutrals collision frequency. This is in agreement with the theory of the slow-ion drift instability induced by themore » collisional slowing of the electric ion drift [A. Simon, Phys. Fluids 6, 382 (1963)].« less