skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Anomalous resistivity of current-driven isothermal plasmas due to phase space structuring

Abstract

The anomalous electric resistivity of collisionless plasmas is an important issue in the physics of hot plasmas, e.g., in the context of auroral particle acceleration and of reconnection in the solar corona. The linear stability theory of isothermal current driven space plasmas predicts an ion-acoustic instability if the relative drift velocity of the current carrying particles exceeds a certain threshold, which, generally, depends on the plasma parameters. The spectrum of waves, excited by a marginal instability, is very narrow. Hence, the wave power at saturation and the corresponding electric resistivity due to wave-particle interaction cannot be obtained by means of a quasilinear, weak turbulence approach and the nonlinear single mode theory provides too small saturation amplitudes. To solve the nonlinear problem a newly developed unsplit conservative Eulerian Vlasov code is applied to simulate a strongly magnetized current driven plasma, which can be considered in 1D1V (one spatial, one velocity space direction). Instead of periodic boundary conditions, usually used as they are simpler to treat, open boundaries are implemented which allow to maintain a constant current flow. Simulated is a typical almost isothermal (T{sub e}=2T{sub i}) hot ({kappa}T{sub i}=1 keV) space plasma for the real mass ratio m{sub i}/m{sub e}=1836. Themore » initial spontaneous instability is followed by a three-stage nonlinear evolution: First electron trapping leads to the formation of electron phase space holes. Due to a steepening of the leading edges of the potential wells the electron phase space holes gradually become asymmetric, they grow in size and deepen. The phase space holes accelerate until they move much faster than the initial ion-acoustic waves. The interaction of the current carriers with the asymmetric potential wells and causes a nonvanishing net momentum transfer between the particles and the self-generated electric field. After a few ion plasma periods ion trapping starts until, finally, an electrostatic double layer arises. It is found that the nonlinear saturated state of the system is dominated by the particle interaction with coherent phase space structures. The corresponding anomalous resistivity is slightly modulated with an oscillation period {tau}{approx_equal}{omega}{sub pi}{sup -1}). For a macroscopic description its major part can be parameterized by means of an effective collision rate {nu}{sub eff} of the order of 10{sup -2}{omega}{sub pe}{approx_equal}0.5{omega}{sub pi}, where {omega}{sub pe} is the electron and {omega}{sub pi} the ion plasma frequency.« less

Authors:
;  [1]
  1. Max-Planck-Institut fuer Sonnensystemforschung, 37191 Katlenburg-Lindau (Germany)
Publication Date:
OSTI Identifier:
20860180
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 13; Journal Issue: 8; Other Information: DOI: 10.1063/1.2209611; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ASYMMETRY; BOLTZMANN-VLASOV EQUATION; BOUNDARY CONDITIONS; COLLISIONLESS PLASMA; COLLISIONS; CURRENTS; ELECTRIC CONDUCTIVITY; ELECTRIC FIELDS; ELECTRONS; HOT PLASMA; ION ACOUSTIC WAVES; IONS; KEV RANGE; LANGMUIR FREQUENCY; LAYERS; NONLINEAR PROBLEMS; PARTICLE INTERACTIONS; PERIODICITY; PHASE SPACE; PLASMA INSTABILITY; PLASMA SHEATH; PLASMA SIMULATION; POTENTIALS; SOLAR CORONA; TRAPPING; TURBULENCE; VELOCITY; WAVE POWER

Citation Formats

Buechner, Joerg, and Elkina, Nina. Anomalous resistivity of current-driven isothermal plasmas due to phase space structuring. United States: N. p., 2006. Web. doi:10.1063/1.2209611.
Buechner, Joerg, & Elkina, Nina. Anomalous resistivity of current-driven isothermal plasmas due to phase space structuring. United States. https://doi.org/10.1063/1.2209611
Buechner, Joerg, and Elkina, Nina. Tue . "Anomalous resistivity of current-driven isothermal plasmas due to phase space structuring". United States. https://doi.org/10.1063/1.2209611.
@article{osti_20860180,
title = {Anomalous resistivity of current-driven isothermal plasmas due to phase space structuring},
author = {Buechner, Joerg and Elkina, Nina},
abstractNote = {The anomalous electric resistivity of collisionless plasmas is an important issue in the physics of hot plasmas, e.g., in the context of auroral particle acceleration and of reconnection in the solar corona. The linear stability theory of isothermal current driven space plasmas predicts an ion-acoustic instability if the relative drift velocity of the current carrying particles exceeds a certain threshold, which, generally, depends on the plasma parameters. The spectrum of waves, excited by a marginal instability, is very narrow. Hence, the wave power at saturation and the corresponding electric resistivity due to wave-particle interaction cannot be obtained by means of a quasilinear, weak turbulence approach and the nonlinear single mode theory provides too small saturation amplitudes. To solve the nonlinear problem a newly developed unsplit conservative Eulerian Vlasov code is applied to simulate a strongly magnetized current driven plasma, which can be considered in 1D1V (one spatial, one velocity space direction). Instead of periodic boundary conditions, usually used as they are simpler to treat, open boundaries are implemented which allow to maintain a constant current flow. Simulated is a typical almost isothermal (T{sub e}=2T{sub i}) hot ({kappa}T{sub i}=1 keV) space plasma for the real mass ratio m{sub i}/m{sub e}=1836. The initial spontaneous instability is followed by a three-stage nonlinear evolution: First electron trapping leads to the formation of electron phase space holes. Due to a steepening of the leading edges of the potential wells the electron phase space holes gradually become asymmetric, they grow in size and deepen. The phase space holes accelerate until they move much faster than the initial ion-acoustic waves. The interaction of the current carriers with the asymmetric potential wells and causes a nonvanishing net momentum transfer between the particles and the self-generated electric field. After a few ion plasma periods ion trapping starts until, finally, an electrostatic double layer arises. It is found that the nonlinear saturated state of the system is dominated by the particle interaction with coherent phase space structures. The corresponding anomalous resistivity is slightly modulated with an oscillation period {tau}{approx_equal}{omega}{sub pi}{sup -1}). For a macroscopic description its major part can be parameterized by means of an effective collision rate {nu}{sub eff} of the order of 10{sup -2}{omega}{sub pe}{approx_equal}0.5{omega}{sub pi}, where {omega}{sub pe} is the electron and {omega}{sub pi} the ion plasma frequency.},
doi = {10.1063/1.2209611},
url = {https://www.osti.gov/biblio/20860180}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 8,
volume = 13,
place = {United States},
year = {2006},
month = {8}
}