Turbulent anomalous transport and anisotropic electron heating in a return current system

Journal Article · Tue Feb 15 04:00:00 EST 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3553026· OSTI ID:21535158

Lee, Kuang Wu; Buechner, Joerg ^[1]

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1. Max-Planck-Institut fuer Sonnensystemforschung, 37191 Katlenburg-Lindau (Germany)

Anisotropic electron heating due to self-generated electromagnetic turbulences is observed in collisionless return current plasmas. The corresponding energy conversion, electron heating, and associated anomalous momentum transport are investigated by means of a two-dimensional electromagnetic particle-in-cell simulation code. The return current model consists of two counterstreaming electron beams with different temperatures and a stationary ion background. First, a general multifluid dispersion analyzer is presented in a clear matrix form that allows to study electron streaming instabilities. The numerical simulation confirms the predicted electrostatic electron-electron acoustic instability. Generating electromagnetic waves, the system evolves into a nonlinear stage. As a result, the electron drifts are slowed down due to turbulence-induced anomalous momentum exchange. Localized electric and magnetic field fluctuations play major roles in the energy conversion. Perpendicular electron heating follows the growth of magnetic field perturbations and the slowing of the electron drifts. Parallel and perpendicular electron heating occurs at different time scales. It is shown that the longer lasting perpendicular electron heating is caused by preheated parallel electron flows. The deflection of the preheated parallel electron flows in the localized turbulences, which is essentially a two-dimensional effect, leads to perpendicular electron heating even after the saturation of parallel electron heating. We conclude that the self-generated magnetic turbulence dominates the anomalous transport process in the late stage of return current system evolution.

• OSTI ID: 21535158
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 2 Vol. 18; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COLLISIONLESS PLASMA
COMPUTERIZED SIMULATION
CONVERSION
ELECTRIC FIELDS
ELECTROMAGNETIC RADIATION
ELECTRON DRIFT
ELECTRONS
ELEMENTARY PARTICLES
ENERGY CONVERSION
FERMIONS
FLUCTUATIONS
HEATING
INSTABILITY
LEPTONS
MAGNETIC FIELDS
PLASMA
PLASMA HEATING
PLASMA INSTABILITY
RADIATIONS
SIMULATION
TURBULENCE
VARIATIONS