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Title: Hall assisted forced magnetic reconnection

Abstract

The role of the Hall effect in forced magnetic reconnection is investigated analytically for the so-called Taylor problem. In the latter, a tearing stable slab plasma equilibrium, which is chosen here to be a simple magnetic field reversal, is subjected to a small-amplitude boundary deformation that drives magnetic reconnection (hence the adjective 'forced') at the neutral surface within the plasma. It is shown that such reconnection becomes substantially accelerated by the Hall effect when the nondimensional parameter d{sub i}=(c/{omega}{sub pi})/a exceeds S{sup -1/5}. Here, c/{omega}{sub pi} is the ion inertial skin depth, a is the width of the plasma slab, and S>>1 is the Lundquist number of a highly conducting plasma. Two different types of external perturbation are considered. In the case of continuous quasistatic driving, with a frequency {omega} such that {omega}{tau}{sub A}<<1, {tau}{sub A} being the Alfven transit time, various reconnection regimes are identified. The corresponding heating rates, which are determined by the parameters d{sub i}, S, and {omega}{tau}{sub A}, are derived. In the case of a 'one-off' reconnection event, we demonstrate when and how the transition from the Hall regime to the magnetohydrodynamic regime occurs in the course of the reconnection process. It is found that themore » peak instantaneous reconnection rate scales as d{psi}{sub 1}(0)/dt{approx}d{sub i}{sup 1/2}S{sup -1/2}(B{sub 0}{delta}{sub 0}/{tau}{sub A}), where {psi}{sub 1}(0) is the reconnected magnetic flux, B{sub 0} is the magnetic field strength, and {delta}{sub 0} is the amplitude of the boundary deformation.« less

Authors:
;  [1]
  1. School of Physics and Astronomy, University of Manchester, Manchester M60 1QD (United Kingdom)
Publication Date:
OSTI Identifier:
20860422
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 13; Journal Issue: 12; Other Information: DOI: 10.1063/1.2398933; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALFVEN WAVES; AMPLITUDES; BOUNDARY LAYERS; DEFORMATION; DISTURBANCES; EQUILIBRIUM; HALL EFFECT; HEATING RATE; MAGNETIC FIELD REVERSAL; MAGNETIC FIELDS; MAGNETIC FLUX; MAGNETIC RECONNECTION; MAGNETOHYDRODYNAMICS; PLASMA; RADIATION TRANSPORT; TEARING INSTABILITY

Citation Formats

Vekstein, G., and Bian, N. H. Hall assisted forced magnetic reconnection. United States: N. p., 2006. Web. doi:10.1063/1.2398933.
Vekstein, G., & Bian, N. H. Hall assisted forced magnetic reconnection. United States. doi:10.1063/1.2398933.
Vekstein, G., and Bian, N. H. Fri . "Hall assisted forced magnetic reconnection". United States. doi:10.1063/1.2398933.
@article{osti_20860422,
title = {Hall assisted forced magnetic reconnection},
author = {Vekstein, G. and Bian, N. H.},
abstractNote = {The role of the Hall effect in forced magnetic reconnection is investigated analytically for the so-called Taylor problem. In the latter, a tearing stable slab plasma equilibrium, which is chosen here to be a simple magnetic field reversal, is subjected to a small-amplitude boundary deformation that drives magnetic reconnection (hence the adjective 'forced') at the neutral surface within the plasma. It is shown that such reconnection becomes substantially accelerated by the Hall effect when the nondimensional parameter d{sub i}=(c/{omega}{sub pi})/a exceeds S{sup -1/5}. Here, c/{omega}{sub pi} is the ion inertial skin depth, a is the width of the plasma slab, and S>>1 is the Lundquist number of a highly conducting plasma. Two different types of external perturbation are considered. In the case of continuous quasistatic driving, with a frequency {omega} such that {omega}{tau}{sub A}<<1, {tau}{sub A} being the Alfven transit time, various reconnection regimes are identified. The corresponding heating rates, which are determined by the parameters d{sub i}, S, and {omega}{tau}{sub A}, are derived. In the case of a 'one-off' reconnection event, we demonstrate when and how the transition from the Hall regime to the magnetohydrodynamic regime occurs in the course of the reconnection process. It is found that the peak instantaneous reconnection rate scales as d{psi}{sub 1}(0)/dt{approx}d{sub i}{sup 1/2}S{sup -1/2}(B{sub 0}{delta}{sub 0}/{tau}{sub A}), where {psi}{sub 1}(0) is the reconnected magnetic flux, B{sub 0} is the magnetic field strength, and {delta}{sub 0} is the amplitude of the boundary deformation.},
doi = {10.1063/1.2398933},
journal = {Physics of Plasmas},
number = 12,
volume = 13,
place = {United States},
year = {Fri Dec 15 00:00:00 EST 2006},
month = {Fri Dec 15 00:00:00 EST 2006}
}