Direct evidence for magnetic reconnection at the boundaries of magnetic switchbacks with Parker Solar Probe
Direct evidence for magnetic reconnection at the boundaries of magnetic switchbacks with Parker Solar Probe
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DOI：
10.1051/0004-6361/202039806
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发表时间：
2021-01
影响因子：
6.5
通讯作者：
C. Froment;V. Krasnoselskikh;T. Dudok de Wit;O. Agapitov;N. Fargette;B. Lavraud;A. Larosa;M. Kretzschmar;V. Jagarlamudi;M. Velli;D. Malaspina;P. Whittlesey;S. Bale;A. Case;K. Goetz;J. Kasper;K. Korreck;D. Larson;R. Macdowall;F. Mozer;M. Pulupa;C. Revillet;M. Stevens
中科院分区：
文献类型：
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作者：
C. Froment;V. Krasnoselskikh;T. Dudok de Wit;O. Agapitov;N. Fargette;B. Lavraud;A. Larosa;M. Kretzschmar;V. Jagarlamudi;M. Velli;D. Malaspina;P. Whittlesey;S. Bale;A. Case;K. Goetz;J. Kasper;K. Korreck;D. Larson;R. Macdowall;F. Mozer;M. Pulupa;C. Revillet;M. Stevens
上下文帕克太阳探测器（PSP）与太阳的第一次相遇揭示了内日球层中普遍存在的局部磁偏转;这些结构，通常称为之字形，在源自日冕洞的太阳风气流中特别引人注目。目标。我们报告的直接证据的磁重联发生在边界的三个之字形的PSP在距离45至48太阳半径的太阳在其第一次遇到。方法.我们分析了磁场和等离子体参数的领域和太阳风电子阿尔法和质子仪器。结果分析的三种结构都显示出磁重联的典型特征。离子速度和磁场的第一个相关，然后反相关的分叉的电流片与中央离子流射流的入站和出站边缘。大多数的重联事件有一个强大的引导场和中等的磁剪切，但一个电流片显示出准反平行重联的迹象与磁场强度下降了90%。结论.由于PSP观测到大量的强电流片，在之字形边界处的重连似乎很罕见。然而，由于之字形边界容纳电流，人们可以推测，这些边界的几何形状提供了有利的条件发生磁重联。因此，这种机制将有助于重新配置之字形的磁场，影响太阳风的动力学，并最终有助于在远离太阳传播时将结构与常规风混合。
Context. The first encounters of Parker Solar Probe (PSP) with the Sun revealed the presence of ubiquitous localised magnetic deflections in the inner heliosphere; these structures, often called switchbacks, are particularly striking in solar wind streams originating from coronal holes. Aims. We report the direct piece of evidence for magnetic reconnection occurring at the boundaries of three switchbacks crossed by PSP at a distance of 45 to 48 solar radii to the Sun during its first encounter. Methods. We analyse the magnetic field and plasma parameters from the FIELDS and Solar Wind Electrons Alphas and Protons instruments. Results. The three structures analysed all show typical signatures of magnetic reconnection. The ion velocity and magnetic field are first correlated and then anti-correlated at the inbound and outbound edges of the bifurcated current sheets with a central ion flow jet. Most of the reconnection events have a strong guide field and moderate magnetic shear, but one current sheet shows indications of quasi anti-parallel reconnection in conjunction with a magnetic field magnitude decrease by 90%. Conclusions. Given the wealth of intense current sheets observed by PSP, reconnection at switchback boundaries appears to be rare. However, as the switchback boundaries accomodate currents, one can conjecture that the geometry of these boundaries offers favourable conditions for magnetic reconnection to occur. Such a mechanism would thus contribute in reconfiguring the magnetic field of the switchbacks, affecting the dynamics of the solar wind and eventually contributing to the blending of the structures with the regular wind as they propagate away from the Sun.