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首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Ion-Scale Wave Properties and Enhanced Ion Heating Across the Low-Latitude Boundary Layer During Kelvin-Helmholtz Instability
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Ion-Scale Wave Properties and Enhanced Ion Heating Across the Low-Latitude Boundary Layer During Kelvin-Helmholtz Instability

机译:在Kelvin-Helmholtz不稳定期间,在低纬度边界层上的离子尺度波形和增强离子加热

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In the Earth's magnetosphere, the magnetotail plasma sheet ions are much hotter than in the shocked solar wind. On the dawn sector, the cold-component ions are more abundant and hotter by 30-40% when compared to the dusk sector. Recent statistical studies of the flank magnetopause and magnetosheath have shown that the level of temperature asymmetry of the magnetosheath is unable to account for this, so additional physical mechanisms must be at play, either at the magnetopause or plasma sheet that contributes to this asymmetry. In this study, we perform a statistical analysis on the ion-scale wave properties in the three main plasma regimes common to flank magnetopause boundary crossings when the boundary is unstable to Kelvin-Helmholtz instability (KHI): hot and tenuous magnetospheric, cold and dense magnetosheath, and mixed (Hasegawa et al., 2004). These statistics of ion-scale wave properties are compared to observations of fast magnetosonic wave modes that have recently been linked to Kelvin-Helmholtz (KH) vortex centered ion heating (Moore et al., 2016). The statistical analysis shows that during KH events there is enhanced nonadiabatic heating calculated during ion scale wave intervals when compared to non-KH events. This suggests that during KH events there is more free energy for ion-scale wave generation, which in turn can heat ions more effectively when compared to cases when KH waves are absent. This may contribute to the dawn favored temperature asymmetry of the plasma sheet; recent studies suggest KH waves favor the dawn flank during Parker-Spiral interplanetary magnetic field.
机译:在地球磁层中,磁靶板离子比震动太阳风更热。与黄昏部门相比,冷组分离子较高,冷 - 组分离子更加丰富30-40%。侧翼磁档和磁性晶孔的最新统计研究表明,磁性晶圈的温度不对称水平无法解释,因此必须在磁性常规或有助于这种不对称的等离子体片处进行额外的物理机制。在这项研究中,我们对侧翼磁档边界交叉的三个主要等离子体制度进行了统计分析,当边界对Kelvin-Helmholtz不稳定(khi)不稳定时:热且脆弱的磁气层,冷和致密磁性晶圈和混合(Hasegawa等,2004)。将离子尺度波属性的这些统计数据与最近与Kelvin-Helmholtz(KH)涡旋中心的离子加热(Moore等,2016)连接的快速磁性波模式的观察。统计分析表明,在KH事件期间,与非KH事件相比,在离子尺度波间隔期间计算的非分配加热增强。这表明在KH事件期间,对于离子尺度波产生,可以更具自由能量,这反过来可以在与kh波的情况相比时更有效地加热离子。这可能有助于黎明的最有利于等离子体片材的温度不对称;最近的研究表明KH波在帕克 - 螺旋行星磁场期间黎明侧翼。

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