High-latitude poynting flux from combined Iridium and SuperDARN data
High-latitude poynting flux from combined Iridium and SuperDARN data
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来自铱星和 SuperDARN 综合数据的高纬度坡印廷通量
DOI：
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发表时间：
2004
期刊：
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通讯作者：
J. Ruohoniemi
中科院分区：
文献类型：
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作者：
C. Waters;B. Anderson;R. Greenwald;R. Barnes;J. Ruohoniemi
抽象的。场对准电流在磁层和电离层之间传递应力，相关的低空磁场和电场反映了电磁能流向极地电离层的情况。我们引入了一种新技术来测量高纬度坡印廷通量的全球分布，S || ，通过将超级双极光雷达网络 (SuperDARN) 的电场估计与使用铱卫星星座磁力计数据得出的磁扰动相结合。使用球谐函数方法合并数据集并计算S ||对于从极点到 60° 磁纬度 (MLAT) 的任何磁本地时间 (MLT)。有效空间分辨率为2° MLAT、2h MLT，由于铱磁力计数据的遥测速率，时间分辨率约为1小时。该技术可以评估高纬度网络 S ||及其在一小时时间尺度上的空间分布，具有两个关键优势：（1）它产生净 S ||包括中性风的贡献； (2) 结果是在不依赖电离层电导率估计的情况下获得的。我们提供两个示例，即 1999 年 11 月 23 日 14:00-15:00 UT 和 2000 年 3 月 11 日 16:00-17:00 UT，以测试该技术的准确性并说明 S || 的分布。它给出的。与原位 S 的比较 || DMSP 卫星的估计表明，在 S || 的位置上，与几 mW/m 2 一致。技术分辨率的增强。这些事件的总电磁能量通量为 50GW。在极光纬度，S ||在 MLAT 中小于 5° 的区域中，在具有 S || 的 MLT 中，倾向于在上午和下午最大化两个小时。 =10至20mW/m 2 总功率高达10GW。区域 1 电流的极地功率约为总功率的三分之一，表明极冠上有显着的能量通量。
Abstract. Field-aligned currents convey stress between the magnetosphere and ionosphere, and the associated low altitude magnetic and electric fields reflect the flow of electromagnetic energy to the polar ionosphere. We introduce a new technique to measure the global distribution of high latitude Poynting flux, S || , by combining electric field estimates from the Super Dual Auroral Radar Network (SuperDARN) with magnetic perturbations derived using magnetometer data from the Iridium satellite constellation. Spherical harmonic methods are used to merge the data sets and calculate S || for any magnetic local time (MLT) from the pole to 60° magnetic latitude (MLAT). The effective spatial resolutions are 2° MLAT, 2h MLT, and the time resolution is about one hour due to the telemetry rate of the Iridium magnetometer data. The technique allows for the assessment of high-latitude net S || and its spatial distribution on one hour time scales with two key advantages: (1) it yields the net S || including the contribution of neutral winds; and (2) the results are obtained without recourse to estimates of ionosphere conductivity. We present two examples, 23 November 1999, 14:00-15:00 UT, and 11 March 2000, 16:00-17:00 UT, to test the accuracy of the technique and to illustrate the distributions of S || that it gives. Comparisons with in-situ S || estimates from DMSP satellites show agreement to a few mW/m 2 and in the locations of S || enhancements to within the technique's resolution. The total electromagnetic energy flux was 50GW for these events. At auroral latitudes, S || tends to maximize in the morning and afternoon in regions less than 5° in MLAT by two hours in MLT having S || =10 to 20mW/m 2 and total power up to 10GW. The power poleward of the Region 1 currents is about one-third of the total power, indicating significant energy flux over the polar cap.