论文标题
MMS观察Whistler和较低的杂化漂移波与湍流磁石中的磁重新连接有关
MMS Observations of Whistler and Lower Hybrid Drift Waves Associated with Magnetic Reconnection in the Turbulent Magnetosheath
论文作者
论文摘要
磁重新连接(MR)和相关的同时发生的波是在大尺度等离子体边界上进行了广泛研究,在陆地磁尾和磁路面的准对称和不对称构型中。最近对MMS(磁层多尺度)航天器进行的高分辨率观察表明,当上游冲击几何形状是准平行时,MR也可以在磁石中发生,该条件高度湍流。强大的湍流运动使MR复杂的边界条件变得复杂。在本文中,证明了MR局部区域的波浪观测可以作为一种额外的诊断工具,增强了我们识别湍流等离子体中MR事件的能力。结果表明,在与MR的密切相似之处在大规模边界时,湍流重新连接相关的惠斯勒波在分离式/流出区域以及电子扩散区域的外边界处发生,而较低的混合漂移波则与当前纸交叉期间的密度梯度相关。较低的杂化漂移不稳定性会使密度不均匀性波动。在磁石中鉴定MR相关波也代表了对湍流等离子体中能量重新分布和耗散的更好理解的重要里程碑。
Magnetic reconnection (MR) and the associated concurrently occurring waves have been extensively studied at large-scale plasma boundaries, in quasi-symmetric and asymmetric configurations in the terrestrial magnetotail and at the magnetopause. Recent high-resolution observations by MMS (Magnetospheric Multiscale) spacecraft indicate that MR can occur also in the magnetosheath where the conditions are highly turbulent when the upstream shock geometry is quasi-parallel. The strong turbulent motions make the boundary conditions for evolving MR complicated. In this paper it is demonstrated that the wave observations in localized regions of MR can serve as an additional diagnostic tool reinforcing our capacity for identifying MR events in turbulent plasmas. It is shown that in a close resemblance with MR at large-scale boundaries, turbulent reconnection associated whistler waves occur at separatrix/outflow regions and at the outer boundary of the electron diffusion region, while lower hybrid drift waves are associated with density gradients during the crossing of the current sheet. The lower hybrid drift instability can make the density inhomogeneities rippled. The identification of MR associated waves in the magnetosheath represents also an important milestone for developing a better understanding of energy redistribution and dissipation in turbulent plasmas.