地球近地空间非震电磁扰动

Non-seismic Induced Electromagnetic Waves in the Near Earth Space

在地球近地空间卫星观测到的来自空间的电磁波动包括：电磁离子回旋波，哨声，嘶声，合声，地磁脉动。其中电磁离子回旋波、等离子体层嘶声和合声都在平静时期可以观测到，但在磁暴、亚暴期间会显著增强。来自地面的电磁扰动有人工产生的，也有自然产生的。人工产生的电磁扰动主要有地面甚低频发射机发射的VLF电磁波和地面电力线路感应的谐频电磁波。自然产牛的电磁丁扰主要有闪电（雷暴）。除了上述自然和人工产生的电磁波动外，卫星本身工作时也可产生频率在0～200Hz范围内的电磁扰动。

In the near Earth space, satellites often observe electromagnetic waves originated from space, which include electromagnetic ion cyclotron waves, whistler waves, hiss,chorus and geomagnetic pulsations. Among these waves, plasmaspheric hiss and chorus can be observed during geomagnetic quiet times, but can be much enhanced during geomagnetic storms and substorms. Those electromagnetic waves originated from the surface of the Earth can be both natural and artificial electromagnetic waves. The artificial electromagnetic waves mainly refer to the VLF waves emitted by VLF transmitters and the harmonic waves produced by power lines. Besides the above-mentioned electromagnetic waves, satellites themselves in operation can also produce electromagnetic noise in the frequency range of 0-200 Hz.