Study of Nonlinear Wave-wave Interaction in the Ionospheric Plasma

在Aureol 3卫星和Sagadaira地面站遥测的许多宽带(0-16 kHz)甚低频数据中，我们发现了一个有趣的新现象，这是迄今为止从未报道过的。这种现象与苏联东部的高功率(500千瓦)甚低频发射机(称为“阿尔法站”)信号有关。在卫星上，我们在某些情况下观察到频谱的多普勒展宽，在其他情况下，我们探测到发射机信号上方和下方的边带结构。前一种现象早在几年前就已被斯坦福大学发现，而后一种现象则是新发现的浪潮现象。基于详细的频谱分析和精细的双谱分析，这些边带结构是极强的甚低频发射机信号与卫星附近存在的离子波(如离子回旋谐波)之间的非线性波-波相互作用(三波过程)的结果。

Among many wide-band(0-16kHz) VLF data observed on Aureol 3 satellite and telemetered onto the ground station of Sagadaira,we have found out an interesting new phenomenon which has never been reported so far. This phenomenon is associated with the high-power (500kwatts) VLF transmitter (called "Alpha station") signals from the eastern USSR. On the satellite, we have observed Doppler broadening of the spectrum on some occasions,and on other occasions, we have detected the side-band structures above and below the transmitter signal. The former phenomenon was already discovered by Stanford group a few years ago,but the latter phenomenon is a newly-found wave phenomenon. Based on the detailed spectral analysis and on the sophisticated bi-spectrum analysis,it is concluded that those side-band structures are the consequence of the nonlinear wave-wave interaction(three-wave process) between the very intense VLF transmitter signal and the ion wave(such as ion cyclotron harmonic wave) existing near the satellite.