利用射线追踪方法研究化学物质释放对高频加热的聚焦效应

Research on the focusing effect of HF heating caused by the chemical release using ray tracing method

电离层化学物质释放能导致释放区域电子密度的损耗,从而产生明显的电离层空洞现象.高频电波通过电离层空洞时,由于电子密度不同,对电波产生折射效果进而形成聚焦效应.本文利用射线追踪方法,评估高频电波通过空洞形成聚焦加热的效果.结果表明,释放水分子与SF_6都能对电离层产生明显的空洞,空洞半径约为25～50 km,电子密度的损耗率10%以上,在释放点附近有时能达到90%.不同摩尔数的化学物质释放能带来不同的效果.在300km高度释放100mol的水分子并且高频电波频率为15 MHz时聚焦效果最好.聚焦后电波能量吸收可增加10 dB左右,增幅达两倍左右.加热后的温度可以提升约20%.

The depletion of ionospheric electron density can be generated by the chemical material release, which is nominated as ionosphere hole. When the HF （high frequency） radio waves propagate through the hole, the refraction of the HF radio waves due to the electron density gradient might form a focusing effect. In this paper the effects of ionospheric focus heating by HF radio wave propagation through ionosphere hole are evaluated using the numerical ray tracing method. The leading numerical results are as follows. Release of H20 and SF6 is able to produce an obvious hole in the ionosphere with radius of 25~50 km approximately; the electron densityls attenuation rate is above 10%, which can sometimes achieve 90~ nearby the release point. Additionally chemical materials of different mole number release can also bring different effects. Focusing effects could reach the best performance at 300 km height by releasing 100 mol H20 when the frequency of the high power radio waves is 15 MHz. Due to the focusing effects, the amplitude of wave energy absorption may raise about 10 dB, which is a twofold increase. After the focused heating the electron temperature may increase approximately 200//oo than the normal HF heating.