Study of Ionospheric Plasma Turbulence Caused by Powerful Ground-Based HF Radio Transmissions

建议继续利用雷达后向散射对电离层等离子体湍流进行观测。1990年和1991年的观测大大增加了对f区反射的无线电波产生的电离层朗缪尔湍流的认识。在提出的观测中，Langmuir湍流的光谱将在每毫秒150米的高度间隔内获得，1991年8月获得的这种类型的初步结果显示了在间隔1毫秒的时间间隔内，在间隔150米的10个高度上，持续时间为10毫秒的脉冲高频传输，Langmuir湍流光谱的时间发展和衰减。本文还提出利用朗缪尔湍流的解析模型进行理论研究。在该模型中，自由朗缪尔模式被认为是调制不稳定性激发的长波等离子体湍流的未捕获部分。对现有的适用于电离层实验的有限磁场的解析模型进行了推广。

It is proposed to continue the observations of ionospheric plasma turbulence by radar back-scatter. Observations in 1990 and 1991 greatly increased the understanding of ionospheric Langmuir turbulence generated by a radio wave reflected in the F-region. In the proposed observations spectra of Langmuir turbulence will be obtained at 150 m height intervals every ms. Preliminary results of this type obtained in August 1991 show the temporal development and decay of the spectrum of Langmuir turbulence for 10 heights 150 m apart, for pulsed HF transmissions of 10 ms duration at 1 ms time intervals. It is also proposed to conduct theoretical investigations using an analytical model of Langmuir turbulence. In that model the free Langmuir mode is considered as the untrapped part of long wavelength plasma turbulence excited by the modulational instability. A generalization of the existing analytical model for the case of a finite magnetic field appropriate for the ionospheric experiments is also proposed.