EMIC waves growth and guiding in the presence of cold plasma density irregularities
EMIC waves growth and guiding in the presence of cold plasma density irregularities
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DOI：
10.1002/grl.50484
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发表时间：
2013-05
影响因子：
5.2
通讯作者：
M. Soria-Santacruz;Maria Spasojevic;Lunjin Chen
中科院分区：
文献类型：
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作者：
M. Soria-Santacruz;Maria Spasojevic;Lunjin Chen
在地磁暴期间，在等离子体层羽流中观测到强烈的电磁离子回旋(EMIC)波，并被认为是环流质子和辐射带电子损失的重要驱动因素。在这项研究中，我们使用射线跟踪和路径积分线性增长计算相结合的方法来分析等离子体层羽流中冷等离子体密度不规则性中EMIC波的放大和传播。在L=5-7的范围内，所有波都在赤道上发射，并分析了波的放大随频率和初始波法角的变化。这些结果与无不规则性的基线情况进行了比较，这表明对于EMIC波长量级的不规则性尺寸，引导是可能的。结果表明，密度水平高于和低于平均值的典型结构可以导致波活动增加和抑制的两个区域。
Intense electromagnetic ion cyclotron (EMIC) waves are observed within plasmaspheric plumes during geomagnetic storms and are believed to be a significant driver of loss of both ring current protons and radiation belt electrons. In this study, we use ray tracing together with path‐integrated linear growth calculations to analyze the amplification and propagation of EMIC waves within cold plasma density irregularities characteristic of the plasmaspheric plume. All waves are launched at the equator in the range of L = 5 to 7, and wave amplification is analyzed as a function of frequency and initial wave normal angle. These results are compared to a baseline case without irregularities, which show that guiding is possible for irregularity sizes on the order of the EMIC wavelength. Results suggest that typical structures with density levels above and below the average value can result in both areas of increased as well as suppressed wave activity.