大功率无线电波加热低电离层

摘要

Abstract The ionospheric heating by powerful High Frequency (HF) radio wave can excite the disturbance of temperature, density and other parameters of ionospheric plasma. Based on Ohmic theory, the effect of high power radio wave on the lower ionosphere is studied, and the following conclusions can be drawn. Firstly, D region is the main absorption area of the radio wave, and the intensity of absorption decreases with the increase of radio wave frequency. When radio frequency is 6 MHz (effective radio power is 200MW), the electron temperature increase can be up to nearly 520 K, and electron density increase can reach about 7300 cm-3. Secondly, the disturbance of electron temperature and density tend to be saturated after continuous heating. The time that the electron temperature needs to be saturated is of a scale of μs, while that of the electron density is ms. Whenstop heating, the electron temperature and density come back to the normal conditions quickly. Thirdly, the higher radio power is, the larger disturbance of electron temperature and density are caused, and the longer saturation time is needed. The saturation time at nighttime is longer than that at daytime under the same heating conditions.%等离子体对大功率电波的欧姆耗散会使电子温度升高，进而导致电子密度和其他等离子体参数改变，实现电离层的地面人工变态．本文基于大功率无线电波与低电离层相互作用的自洽模型，分析了不同入射条件下电离层参数的变化，主要结论如下：电离层D区是电波的主要吸收区，并且其吸收强度随入射频率的升高而降低，当入射频率为6MHz（有效入射功率为200MW）时电子温度的最大增幅约为520K，电子密度最大增幅为7300cm-3左右；电子温度达到饱和所需时间小于电子密度的饱和时间，前者具有μs量级，后者具有ms量级；停止加热后，电子温度和密度迅速恢复到初始状态，恢复时间均小于各自的饱和时间，但量级相当；入射功率越高，电子温度和密度的增幅越大，并且饱和时间也越长，在相同入射条件下，夜晚的饱和时间要大于白天．