论文标题
地球磁石中动力学耗散的统计数据-MMS观测
Statistics of Kinetic Dissipation in Earth's Magnetosheath -- MMS Observations
论文作者
论文摘要
空间和天体物理等离子体中的一个熟悉的问题是了解耗散和加热是如何发生的。这些影响通常归因于一系列宽带湍流，该湍流将能量从大规模的储层转移到小规模的动力学自由度。当碰撞很少时，未建立局部热力学平衡。在这种情况下，能量转化的最后阶段比流体情况更复杂，并且压力 - 稀释和压力应变相互作用（PI-D $ \ equiv-equiv-equ_ {ij} d_ {ij {ij} $）变得相关且潜在的重要性。到目前为止，已经研究了血浆湍流中的PI-D。本研究使用磁层多尺度任务的独特测量能力（MMS）任务提供了地球磁盘中PI-D的统计分析。我们发现，在这种天然存在的等离子体环境中，PI-D的统计数据与先前确定的完全动力学模拟结果表现出很强的相似之处。能量的转换集中在太空中，并且发生在强烈的电流板附近，但不在其中。这支持了最新的建议，即能量传递通道链涉及区域而不是角度相关性。
A familiar problem in space and astrophysical plasmas is to understand how dissipation and heating occurs. These effects are often attributed to the cascade of broadband turbulence which transports energy from large scale reservoirs to small scale kinetic degrees of freedom. When collisions are infrequent, local thermodynamic equilibrium is not established. In this case the final stage of energy conversion becomes more complex than in the fluid case, and both pressure-dilatation and pressure strain interactions (Pi-D $\equiv -Π_{ij} D_{ij}$) become relevant and potentially important. Pi-D in plasma turbulence has been studied so far primarily using simulations. The present study provides a statistical analysis of Pi-D in the Earth's magnetosheath using the unique measurement capabilities of the Magnetospheric Multiscale (MMS) mission. We find that the statistics of Pi-D in this naturally occurring plasma environment exhibit strong resemblance to previously established fully kinetic simulations results. The conversion of energy is concentrated in space and occurs near intense current sheets, but not within them. This supports recent suggestions that the chain of energy transfer channels involves regional, rather than pointwise, correlations.
