Hall magnetohydrodynamic reconnection in the plasmoid unstable regime

S. D. Baalrud; A. Bhattacharjee; Y. -M. Huang; K. Germaschewski

doi:10.1063/1.3633473

paper

Hall magnetohydrodynamic reconnection in the plasmoid unstable regime

arXiv:1108.3129 · doi:10.1063/1.3633473

Abstract

A set of reduced Hall magnetohydrodynamic (MHD) equations are used to evaluate the stability of large aspect ratio current sheets to the formation of plasmoids (secondary islands). Reconnection is driven by resistivity in this analysis, which occurs at the resistive skin depth $d_{η} \equiv S_{L}^{- 1/2} L v_{A} / γ$ , where $S_{L}$ is the Lundquist number, $L$ the length of the current sheet, $v_{A}$ the Alfvén speed, and $γ$ the growth rate. Modifications to a recent resistive MHD analysis [N.\ F.\ Loureiro, A.\ A.\ Schekochihin, and S.\ C. Cowley, Phys.\ Plasmas {\bf 14}, 100703 (2007)] arise when collisions are sufficiently weak that $d_{η}$ is shorter than the ion skin depth $d_{i} \equiv c / ω_{p i}$ . Secondary islands grow faster in this Hall MHD regime: the maximum growth rate scales as $(d_{i} / L)^{6/13} S_{L}^{7/13} v_{A} / L$ and the number of plasmoids as $(d_{i} / L)^{1/13} S_{L}^{11/26}$ , compared to $S_{L}^{1/4} v_{A} / L$ and $S^{3/8}$ , respectively, in resistive MHD.

8 pages, 9 figures, to appear in Physics of Plasmas

References in corpus (1)

Instability of current sheets and formation of plasmoid chains

Hall magnetohydrodynamic reconnection in the plasmoid unstable regime

Abstract

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