Direct determination of large‐scale magnetospheric field‐aligned currents with SuperDARN
Direct determination of large‐scale magnetospheric field‐aligned currents with SuperDARN
复制标题
使用 SuperDARN 直接测定大尺度磁层场对准电流
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
W. Bristow
中科院分区：
文献类型：
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作者：
G. Sofko;R. Greenwald;W. Bristow
SuperDARN（Super Dual A_uroral Radar Network）雷达测量了高纬F区等离子体对流速度v的大尺度二维图像。从二维对流图，等离子体流涡度可以直接计算。我们表明，涡度是Jm/，，p的直接测量值，即每单位高度积分佩德森电导率/v的场向电流（FAC）的“磁层”分量Jm。Jm/P的地图清楚地显示了区域0、1和2电流，未受到电离层佩德森和霍尔电导率梯度（这在夜侧亚暴区很重要）引起的“电离层”FAC分量Ji的污染。本文解释了由SuperDARN对流涡度产生Jm/gp大尺度磁层FAC图像的过程，并给出了加拿大萨斯卡通和Kapus-kasing的SuperDARN雷达对在向北和向南IMF条件下昼侧FAC图像的例子。到1995年夏季，将可从三对北方半球的SuperDARN雷达和一对南极雷达获得FAC图象，这三对雷达的视场在MLT（从加拿大西部到斯堪的纳维亚半岛）上延伸约12小时。
The SuperDARN (Super Dual A_uroral Radar Network) radars measure large-scale 2D images of the plasma convection velocity v in the high-latitude F-region. From the 2D convection maps, plasma flow vorticity can be directly calculated. We show that the vorticity is a direct measure of Jm/,,p, the "magnetospheric" component Jm of the field-aligned current (FAC) per unit height-integrated Pedersen conductivity /v. The maps of Jm/P show clearly the Region 0, 1, and 2 currents, uncontaminated by the "ionospheric" FAC component Ji caused by ionospheric Pedersen and Hall conductivity gradients (which are important in the nightside substorm sector). The generation of the large-scale magnetospheric FAC images of Jm/gp from the SuperDARN convection vorticity is explained and examples of dayside FAC patterns for northward and southward IMF conditions are presented for the SuperDARN radar pair in Canada at Saskatoon and Kapus- kasing. By summer, 1995, FAC images will be available from three northern hemisphere SuperDARN radar pairs, with a field-of-view extending over some 12 hours MLT (from western Canada to Scandinavia), and from one Antarctic radar pair.