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arXiv 1108.3129physics.plasm-ph
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等离子体团不稳定区的霍尔磁流体动力学重联

Hall magnetohydrodynamic reconnection in the plasmoid unstable regime

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

摘要:

一组约化的霍尔磁流体动力学(MHD)方程被用来评估大纵横比电流片的稳定性等离子体团(二次岛)的形成。在该分析中,重新连接由电阻率驱动,其发生在电阻趋肤深度$d_η\equiv S_L^{-1/2} \sqrt{L v_A/γ}$处,其中$S_L$是伦德奎斯特数,$L$是电流片的长度,$v_A$是阿尔文速度,并且$γ$是生长速率。对最近的电阻MHD分析的修正[N.] F. Loureiro,A. A. Schekochihin和S. C. Cowley,Phys.等离子体{ \bf 14},100703(2007)]在碰撞足够弱使得$d_η$短于离子趋肤深度$d_i \equiv c/ω_{pi}$时产生。次级岛在这种霍尔MHD制度中生长得更快:与电阻性MHD中的$S_L^{1/4} v_A/L$和$S^{3/8}$相比,最大生长速率缩放为$(d_i/L)^{6/13} S_L^{7/13} v_A/L$,等离子体团的数量缩放为$(d_i/L)^{1/13} S_L^{11/26}$。

英文摘要:

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 $d_η\equiv S_L^{-1/2} \sqrt{L v_A/γ}$, 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 $d_i \equiv c/ω_{pi}$. 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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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