电离层不规则结构的等效厚度和漂移速度对闪烁功率谱的影响

利用由衍射基本原理导出的有限厚薄相屏弱闪烁信号强度的Ｆｏｕｒｉｅｒ功率谱表达式研究了不规则结构等效厚度Ｌ和水平漂移速度Ｖ对Ｆｏｕｒｉｅｒ功率谱的影响．结果表明，Ｌ加大，Ｆｒｅｓｎｅｌ振幅变小，Ｐｒｅｓｎｅｌ半径不变；Ｖ加大，Ｆｒｅｓｎｅｌ振幅不变，Ｆｒｅｓｎｅｌ半径变大．功率极小值相应的频率值之比为１：２：３：．．．：ｎ而不是１：２、：３：．．．：ｎ，与实测资料分析结果一致．对实测闪烁功率谱进行了数值模拟．由此得到了实际电离层不规则结构等效厚度、漂移速度的数值．

THE EFFECTS OF EQUIVALENT THICKNESS AND DRIFT VELOCITY ON SCINTILLATION POWER SPECTUM IN IONOSPHERIC IRREGULAR STRUCTURE

By use of the Fourier power expression of scintillation intensity of thin phase screen with limited thickness L, which is derived from principle theory of diffraction, the effects of the equivalent thickness L-and the drift velocity V on the Fourier power spectum are studied. The results show that, as L increases, the Fresnel oscillation amplitude decreases and the Fresnel radius remains unchanged; as V increrases, the Fresnel oscillation amplitude remains unchanged and tEe Fresnel radius increases. The ratio of sequent frequences corresponding to the minimum values of poker is 1:2:3:.:n, not 1:2:3: n this is in good agreement with the observationa .data. Comparing the computer comulation results of power spectum wih observational data, both the,values of equivalent thickness and me drift velocity of real ionospheric irregular structure are obtained.