First E region observations of mesoscale neutral wind interaction with auroral arcs
First E region observations of mesoscale neutral wind interaction with auroral arcs
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DOI：
10.1029/2009ja014697
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发表时间：
2010-02
影响因子：
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通讯作者：
M. Kosch;C. Anderson;R. Makarevich;B. Carter;R. Fiori;M. Conde;P. Dyson;T. Davies
中科院分区：
文献类型：
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作者：
M. Kosch;C. Anderson;R. Makarevich;B. Carter;R. Fiori;M. Conde;P. Dyson;T. Davies
本文报道了在南极洲莫森地磁静条件下首次观测到的E区中性风场及其与中尺度极光弧的相互作用。这是通过使用扫描多普勒成像仪实现的，该成像仪可以在宽视场内同时观测热层中性视线风和温度。在两种情况下，背景E区域风场垂直于极光弧，当它出现时，导致在弧的沿着弧平行旋转，在弧消失时恢复到背景气流方向。这在向西和向东的等离子体对流下都观察到。风的旋转发生在7 - 16分钟。在一种情况下，作为极光弧从地平线向当地天顶传播，背景E区域风场变得显着减弱，但仍然不受影响的弧没有通过。我们通过建模表明，这些影响不能解释的高度变化的发射层。最可能的解释似乎是与等离子体密度增加和极光弧相关的局部电离层电场有关的离子阻力大大增强。在所有情况下，F区中性风似乎受极光弧的影响较小，尽管它的存在在数据中很清楚。
We report the first observations of E region neutral wind fields and their interaction with auroral arcs at mesoscale spatial resolution during geomagnetically quiet conditions at Mawson, Antarctica. This was achieved by using a scanning Doppler imager, which can observe thermospheric neutral line-of-sight winds and temperatures simultaneously over a wide field of view. In two cases, the background E region wind field was perpendicular to an auroral arc, which when it appeared caused the wind direction within ∼50 km of the arc to rotate parallel along the arc, reverting to the background flow direction when the arc disappeared. This was observed under both westward and eastward plasma convection. The wind rotations occurred within 7–16 min. In one case, as an auroral arc propagated from the horizon toward the local zenith, the background E region wind field became significantly weaker but remained unaffected where the arc had not passed through. We demonstrate through modeling that these effects cannot be explained by height changes in the emission layer. The most likely explanation seems to be the greatly enhanced ion drag associated with the increased plasma density and localized ionospheric electric field associated with auroral arcs. In all cases, the F region neutral wind appeared less affected by the auroral arc, although its presence is clear in the data.