电离层加热激发受激布里渊散射研究

Stimulated Brillouin scattering in ionospheric modification

研究了电离层加热激发受激布里渊散射效应.利用受激布里渊散射匹配条件,结合国际地磁场参考模型,模拟计算了离子声波(Ion Acoustic,IA)与静电离子回旋波(Electrostatic Ion Cyclotron,EIC)频率随地理纬度、加热频率、波束指向、电子温度等参数变化特性,并以我国海南与美国高频主动极光研究项目(High Frequency Active Auroral Research Program,HAARP)为例,研究IA与EIC频率随纬度的变化.模拟结果表明:随着纬度的增加,IA与EIC频率增大;与IA频率相比,EIC频率随加热频率、波束指向及电子温度的变化相对较小;随加热频率的增加高纬地区IA频率增大,而低纬地区基本不变;随加热波束指向从南到北变化,海南IA频率单调下降,HAARP则为先上升后下降的形态,EIC具有相反的变化;电子温度越高,IA与EIC频率越大.本文模拟结果可为我国将来开展同类实验提供参考.

The stimulated Brillouin scattering（SBS）in ionospheric modification by high power HF radio waves is studied.Based on momentum and energy conservation equations and dispersion relations,the SBS matching conditions are given briefly.The variations of frequencies of ion acoustic（IA）and electrostatic ion cyclotron（EIC）stimulated by SBS are calculated with different parameters including altitudes,heating frequency,the direction of pumping wave and electron temperature at perturbed region.The different of IA and EIC frequency between low and high latitude are compared taking Hainan and HAARP as examples.The simulation results show that：the stimulated electrostatic low frequency increases as the latitude increases;the frequency of EIC changes less than IA with the variation of heating frequency,the direction of pumping wave and electron temperature at perturbed region;along with increased pump frequency,the IA frequency at high latitude increases,but at low latitude the IA frequency almost keep constant;as the direction of pump wave changes from south to north,the IA frequency in Hainan decreases,but in HAARP it increases until the geomagnetic direction,and the EIC frequency is reverse;the increased electron temperature will increase IA and EIC frequency.These results provide support for our future experiments.