基于加热激发等离子体线级联结构的电子密度反演

Inversion of ambient electron density for the modified ionosphere from HF pumping induced plasma cascade lines

2010年9月13日,利用欧洲非相干散射雷达协会的大功率加热设备和诊断设施开展了电离层加热实验,实验中首次由甚高频雷达探测到了长生命周期的等离子体线增强现象.通过对等离子体线的频谱分析,发现了等离子体线的cascade频谱结构,并推断参量衰变不稳定性是引起实验中等离子体线回波功率增强的原因.同时依据参量衰变不稳定性理论,给出了一种利用cascade频谱结构对加热区域电离层的电子密度反演的方法,并将反演得到的电子密度与利用有效超高频雷达数据的程序GUISDAP反演结果进行了对比,验证了该方法的正确性,分析结果表明反演结果的平均偏差仅在1%左右.新方法的提出对强扰动电离层条件下电离层参数的反演及深入理解电波能量的吸收机制和朗缪尔湍流加速电子的过程具有重要意义.

The ionospheric heating experiments were carried out with the EISCAT heating and diagnosing facilities on September 13,2010 at Troms,Norway.The long-lasting enhanced plasma lines were first observed by the ground-based VHF radar.Through the analysis of the plasma spectra,a cascade structure is discovered,inferring that the enhanced lines observed in the experiment may be caused by the parametric decay instability(PDI).In addition,an inversion method of electron density for the modified ionosphere is developed by using the cascade spectrum,which is verified by aquantitative comparison with the traditional grand unified incoherent scatter design and analysis package(GUISDAP)inversion that utilizes the reliable UHF radar data to hold an average deviation of~ 1% for the inversion results.This method is of significant importance to evaluating the parameters of strongly modified ionosphere and improving the understanding of the power absorption of radio waves and the electron acceleration by the Langmuir turbulence.