The Low‐Latitude Boundary Layer in the Tail‐Flanks
The Low‐Latitude Boundary Layer in the Tail‐Flanks
复制标题
尾翼的低纬度边界层
DOI：
10.1029/gm105p0033
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发表时间：
2013
影响因子：
2.2
通讯作者：
T. Mukai
中科院分区：
文献类型：
--
作者：
M. Fujimoto;T. Terasawa;T. Mukai
对尾部低纬度边界层（LLBL）的地尾巴观测表明，冷密度离子出现在这里，具有停滞流特征，并伴有双向热电子（< 300 eV）。从这些研究结果可以得出结论，尾LLBL是捕获的磁鞘起源的冷密等离子体的磁层的闭合场线的网站。也有一些例子表明，从侧面进入的冷密度等离子体可能对填充磁尾的相当大的一部分很重要。在这种情况下，主要是在向北的IMF间隔期间检测到，冷密度等离子体在空间上不限于附着在磁层顶（LLBL）上的层，而是继续在磁尾内部，构成冷密度等离子体片，冷密等离子体从磁层边界一路的连续性强有力地支持了磁鞘离子直接供应到冷密等离子体中的想法。密集的等离子体片这种在近地区域的冷密度等离子体显示出显着的对比与标称热稀薄的等离子体推测从遥远的尾巴。一项统计研究表明，IMF B z分量对近地等离子体片状态有显著的控制作用，这支持了这样一种观点，即在向北的IMF期间，从侧翼向近地尾部的冷密离子供应占主导地位，而从远处尾部向北的热稀薄离子运输占主导地位。我们认为，等离子体片的形成过程不同，根据IMF B z分量。
Geotail observations of the low-latitude boundary layer (LLBL) in the tail-flanks show that it is where the cold-dense ions appear with stagnant flow signatures accompanied by bi-directional thermal electrons (< 300 eV). It is concluded from these findings that the tail-LLBL is the site of capturing the cold-dense plasma of the magnetosheath origin on to the closed field lines of the magnetosphere. There are also cases suggesting that the cold-dense plasma entry from the flanks can be significant to fill a substantial part of the magnetotail. In such cases, which are detected mostly during northward IMF intervals, the cold-dense plasma is not spatially restricted to a layer attached to the magnetopause(LLBL) but continues to well inside the magnetotail, constituting the cold-dense plasma sheet, The continuity of the cold-dense plasma all the way from the magnetospheric boundary strongly supports the idea that the magnetosheath ions are directly supplied into the cold-dense plasma sheet from the flank. This cold-dense plasma in the near-Earth region shows significant contrast with the nominal hot-tenuous plasma presumably transported from the distant tail. A statistical study showing significant control on the near-Earth plasma sheet status by the IMF B z component supports the idea that the cold-dense ion supply to the near-Earth tail from the flanks dominates over the hot-tenuous ion transport from the distant tail during northward IMF periods. We suggest that the formation processes of the plasma sheet differ according to the IMF B z component.