Modulation of total electron content by ULF Pc5 waves
Modulation of total electron content by ULF Pc5 waves
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ULF Pc5 波对总电子含量的调制
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
M. Engebretson
中科院分区：
文献类型：
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作者：
V. Pilipenko;V. Belakhovsky;D. Murr;E. Fedorov;M. Engebretson
在分析来自全球定位系统（GPS）信号的总电子含量（TEC）的小尺度变化时，发现了一个有趣的效应。在2003年10月31日强磁暴的恢复阶段，我们发现TEC变化对全球Pc 5强脉动的响应，其周期为几个毫赫兹，覆盖经校正的地磁纬度~58°-75°。早期的研究表明，GPS-TEC技术是研究由地震或内部重力波产生的电离层瞬态扰动传播模式的有力方法。这种技术已被证明是足够敏感的超低频波以及。在强烈的Pc 5地磁波活动期间，在斯堪的纳维亚高纬度GPS接收站的TEC数据中发现了具有相同周期性的明显脉动。小波和交叉谱分析表明，地磁和TEC的周期性变化之间具有很高的相干性（~0.9）。TEC周期波动的相对幅度ΔTEC/TEC与地磁变化的相对幅度ΔB/B相当甚至更大。到目前为止，Pc 5波对TEC的调制效应还没有得到很好的理解，这对MHD波理论仍然是一个挑战。各种可能的调制机制已被估计，但没有机制已被确定。
An intriguing effect was found while analyzing the small‐scale variations of total electron content (TEC) derived from global positioning system (GPS) signals. We found a response in TEC variations to intense global Pc5 pulsations with periods of a few millihertz covering the corrected geomagnetic latitudes ~58°–75° during the recovery phase of the strong magnetic storms on 31 October 2003. Earlier studies demonstrated that the GPS‐TEC technique is a powerful method to study the propagation pattern of transient disturbances in the ionosphere, generated by seismic or internal gravity waves. This technique has turned out to be sensitive enough to ULF waves as well. During periods with intense Pc5 geomagnetic wave activity, distinct pulsations with the same periodicity were found in the TEC data from high‐latitude GPS receiving stations in Scandinavia. Wavelet and cross‐spectral analysis showed a high coherence (~0.9) between the periodic geomagnetic and TEC variations. Moreover, the relative amplitude of TEC periodic fluctuations ΔTEC/TEC was about or even larger than the relative amplitude of geomagnetic variations ΔB/B. So far, the effect of TEC modulation by Pc5 waves is not well understood and is still a challenge for the MHD wave theory. Various possible modulation mechanisms have been estimated, but no mechanism has been firmly identified.