Propagation and linear mode conversion of magnetosonic and electromagnetic ion cyclotron waves in the radiation belts
Propagation and linear mode conversion of magnetosonic and electromagnetic ion cyclotron waves in the radiation belts
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DOI：
10.1002/2016gl070216
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发表时间：
2016-10
影响因子：
5.2
通讯作者：
R. Horne;Y. Miyoshi
中科院分区：
文献类型：
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作者：
R. Horne;Y. Miyoshi
磁声波和电磁离子回旋波是电子加速和辐射带损失的重要因素。一般认为，这些波是由地磁扰动期间形成的不稳定离子分布产生的。在这里，我们表明，磁声波可以作为一个源的EMIC波的传播和线性模式转换的过程的结果。匡威也是可能的。我们提出射线追踪来展示以大（小）波法线角发射的磁声波（EMIC）如何到达波法线角为零且波频率等于所谓的交叉频率的位置，从而能量可以从一种模式转换到另一种模式而不会衰减。当EMIC波可以是低于交叉频率的磁声波的源时，磁声波可以是氢带波而不是氦带波的源。
Magnetosonic waves and electromagnetic ion cyclotron (EMIC) waves are important for electron acceleration and loss from the radiation belts. It is generally understood that these waves are generated by unstable ion distributions that form during geomagnetically disturbed times. Here we show that magnetosonic waves could be a source of EMIC waves as a result of propagation and a process of linear mode conversion. The converse is also possible. We present ray tracing to show how magnetosonic (EMIC) waves launched with large (small) wave normal angles can reach a location where the wave normal angle is zero and the wave frequency equals the so‐called crossover frequency whereupon energy can be converted from one mode to another without attenuation. While EMIC waves could be a source of magnetosonic waves below the crossover frequency, magnetosonic waves could be a source of hydrogen band waves but not helium band waves.