Three-dimensional magnetic reconnection in particle-in-cell simulations of anisotropic plasma turbulence
Three-dimensional magnetic reconnection in particle-in-cell simulations of anisotropic plasma turbulence
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DOI：
10.1017/s0022377821000404
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发表时间：
2021-03
影响因子：
2.5
通讯作者：
Jeffersson A. Agudelo Rueda;D. Verscharen;R. Wicks;C. Owen;G. Nicolaou;A. Walsh;I. Zouganelis;K. Germaschewski;S. Vargas Domínguez
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作者：
Jeffersson A. Agudelo Rueda;D. Verscharen;R. Wicks;C. Owen;G. Nicolaou;A. Walsh;I. Zouganelis;K. Germaschewski;S. Vargas Domínguez
我们使用三维（3-D）完全动力学粒子在细胞模拟研究磁重联的发生在各向异性反向传播的低频Alfvén波与临界平衡理论一致的衰减湍流的模拟。我们观察到的小规模的电流密度结构，如电流丝和电流片的形成，以及形成的磁通绳的湍流级联的一部分。在模拟域中存在的大的磁结构保持初始各向异性，而湍流级联产生的小尺度结构的各向异性较小。为了量化在我们的模拟域中重连的发生，我们开发了一套新的指标，强度阈值的基础上，以确定重连事件中，离子和电子都被加热和加速在3-D粒子在细胞模拟。根据这些指标的应用，我们确定了重联事件的发生在模拟域中，并详细分析了这些事件之一。这一事件与两条磁绳的重联有关，相关的离子和电子排气呈现出复杂的三维结构。我们研究的档案等离子体和磁场波动记录沿着人造航天器的轨迹附近，并通过重联区。我们的研究结果表明，粒子加热和加速的存在下产生的各向异性Alfvénic湍流级联在太阳风中的磁通绳内的小尺度重联事件。这些事件与电流结构的顺序的几个离子惯性长度的大小。
We use three-dimensional (3-D) fully kinetic particle-in-cell simulations to study the occurrence of magnetic reconnection in a simulation of decaying turbulence created by anisotropic counter-propagating low-frequency Alfvén waves consistent with critical-balance theory. We observe the formation of small-scale current-density structures such as current filaments and current sheets as well as the formation of magnetic flux ropes as part of the turbulent cascade. The large magnetic structures present in the simulation domain retain the initial anisotropy while the small-scale structures produced by the turbulent cascade are less anisotropic. To quantify the occurrence of reconnection in our simulation domain, we develop a new set of indicators based on intensity thresholds to identify reconnection events in which both ions and electrons are heated and accelerated in 3-D particle-in-cell simulations. According to the application of these indicators, we identify the occurrence of reconnection events in the simulation domain and analyse one of these events in detail. The event is related to the reconnection of two flux ropes, and the associated ion and electron exhausts exhibit a complex 3-D structure. We study the profiles of plasma and magnetic-field fluctuations recorded along artificial-spacecraft trajectories passing near and through the reconnection region. Our results suggest the presence of particle heating and acceleration related to small-scale reconnection events within magnetic flux ropes produced by the anisotropic Alfvénic turbulent cascade in the solar wind. These events are related to current structures of the order of a few ion inertial lengths in size.