Reconnection and small-scale fields in 2D-3V hybrid-kinetic driven turbulence simulations
Reconnection and small-scale fields in 2D-3V hybrid-kinetic driven turbulence simulations
复制标题
DOI：
10.1088/1367-2630/aa5c4a
复制
发表时间：
2017-02-21
影响因子：
3.3
通讯作者：
Califano, F.
中科院分区：
文献类型：
--
作者：
Cerri, S. S.;Califano, F.
对无碰撞等离子体（如太阳风）湍流的基本特性的理解是等离子体物理学的前沿问题。特别是，在湍流等离子体中磁重联的发生及其与充分发展的湍流状态的相互作用仍然是一个有很大争议的问题。本文利用2D-3V高分辨率Vlasov-Maxwell模拟研究了小尺度电磁波动的性质和快速磁重联在准稳态湍流发展中的作用。在最大的尺度上，湍流是由外部随机力供给的。我们表明，大规模湍流运动在k（垂直于）d(i) < 1处建立了- 5/3谱，同时，在磁重联发生的地方形成了电流片。结果产生了相干磁结构，伴随着相关的小尺度非理想电场的上升，介导了惯性谱和亚质子谱之间的跃迁。一种促进磁重联过程的机制被确定，使相干结构的产生足够快，足以与波模式相互作用竞争，并导致在所谓的离子断裂上形成一个完全发展的湍流谱。
The understanding of the fundamental properties of turbulence in collisionless plasmas, such as the solar wind, is a frontier problem in plasma physics. In particular, the occurrence of magnetic reconnection in turbulent plasmas and its interplay with a fully-developed turbulent state is still a matter of great debate. Here we investigate the properties of small-scale electromagnetic fluctuations and the role of fast magnetic reconnection in the development of a quasi-steady turbulent state by means of 2D-3V high-resolution Vlasov-Maxwell simulations. At the largest scales turbulence is fed by external random forcing. We show that large-scale turbulent motions establish a - 5/3 spectrum at k(perpendicular to) d(i) < 1and, at the same time, feed the formation of current sheets where magnetic reconnection occurs. As a result coherent magnetic structures are generated which, together with the rise of the associated small-scale non-ideal electric field, mediate the transition between the inertial and the subproton-scale spectrum. A mechanism that boosts the magnetic reconnection process is identified, making the generation of coherent structures rapid enough to be competitive with wave mode interactions and leading to the formation of a fully-developed turbulent spectrum across the so-called ion break.