Density cavity in magnetic reconnection diffusion region in the presence of guide field
Density cavity in magnetic reconnection diffusion region in the presence of guide field
复制标题
存在导场时磁重联扩散区的密度空腔
DOI：
10.1029/2010ja016324
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发表时间：
2011-06
影响因子：
--
通讯作者：
Huang, S. Y.
中科院分区：
文献类型：
--
作者：
Zhou, M.;Pang, Y.;Deng, X. H.;Yuan, Z. G.;Huang, S. Y.
[1]理解磁场重联扩散区的结构对于确定磁场向等离子体的能量转换机制至关重要。具有引导场的扩散区域的特性（即，分量重连）可能显著不同于没有引导场的扩散区（即，反平行重联）。在这项研究中，我们试图通过研究沿着分界线的密度腔来理解具有引导场的扩散区的结构。我们提出了一个事件，其中一个密度腔检测到的集群航天器在扩散区中的引导场的存在。空洞位于中性片南半球分界线附近，X线向地，与强磁场压缩相吻合。空腔的宽度在离子惯性尺度上。该腔中存在较强的反平行电流，主要由能量为1-10 keV的平行电子流贡献。在腔体内观察到低杂波和电磁哨声波的增强。这些波可能是由电子束不稳定性引起的沿沿着分界线的平行电子流激发的。采用二维电磁粒子模拟方法研究了密度腔的结构。空洞的位置和规模以及电流和电子速度的特征与我们的观测结果一致。结果表明，在有引导场的重联过程中，电子密度最小值与面外磁场最大值之间存在位移。然而，这种位移远小于无导场重联时的位移。电子在腔中没有明显的加速以达到大于30 keV的能量。
[1] Understanding the structure of the diffusion region of magnetic reconnection is crucial to pinpoint the mechanism of energy conversion from magnetic field to plasma. Characteristics of a diffusion region with guide field (i.e., component reconnection) may be significantly different from those of a diffusion region without guide field (i.e., antiparallel reconnection). In this study, we attempt to understand the structure of a diffusion region with guide field by studying the density cavity along separatrix. We present an event in which a density cavity was detected by the Cluster spacecraft in a diffusion region in the presence of guide field. The cavity was located around the separatrix region on the southern hemisphere of the neutral sheet and earthward of the X-line and was coincident with strong magnetic field compression. The width of the cavity was on the ion inertial scale. This cavity contained a relatively strong antiparallel current, which was mainly contributed by parallel streaming electrons with energy of 1–10 keV. Enhancements of lower hybrid wave and electromagnetic whistler wave were observed inside the cavity. These waves are probably excited by parallel streaming electrons along separatrix via electron beam instability. Two-dimensional electromagnetic particle-in-cell simulation was employed to study the structure of the density cavity. The location and scale of the cavity and the signature of electric current and electron velocity are consistent with our observations. It is found that there was displacement between the position of electron density minimum and out-of-plane magnetic field maximum in reconnection with guide field. However, this displacement is much less than that in reconnection without guide field. There was no significant acceleration for electrons to reach energy larger than 30 keV at the cavity.
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影响因子：
10.3
作者：
Georg Gustafsson;R. Boström;B. Holback;G. Holmgren;A. Lundgren;Krzysztof Stasiewicz;L. Åhlén;
通讯作者：
Georg Gustafsson;R. Boström;B. Holback;G. Holmgren;A. Lundgren;Krzysztof Stasiewicz;L. Åhlén;
影响因子：
2.2
作者：
Daughton, William;Scudder, Jack;Karimabadi, Homa
通讯作者：
Karimabadi, Homa
影响因子：
--
作者：
Shiyong Huang;Meng Zhou;F. Sahraoui;X. Deng;Y. Pang;Z. Yuan;Q. Wei;J. Wang;Xueying Zhou
通讯作者：
Shiyong Huang;Meng Zhou;F. Sahraoui;X. Deng;Y. Pang;Z. Yuan;Q. Wei;J. Wang;Xueying Zhou
影响因子：
--
作者：
T. Nagai;I. Shinohara;M. Fujimoto;S. Machida;R. Nakamura;Y. Saito;T. Mukai
通讯作者：
T. Nagai;I. Shinohara;M. Fujimoto;S. Machida;R. Nakamura;Y. Saito;T. Mukai
影响因子：
8.6
作者：
A. Teste;G. Parks
通讯作者：
A. Teste;G. Parks