磁化电离层等离子体异常吸收效应研究

摘要

The amplitude anomalous absorption of an O-mode low-power diagnostic radio wave passing through the perturbed region in ionospheric modification is investigated.Kinetic theory and Vlasov equation describing electron dynamics are employed to derive the coefficient of anomalous absorption caused by artificial field-aligned irregularities,considering effects of a magnetic field on the dispersion relationship of EM waves and on motions of electrons in calculations of the displacement current density.With analytical expressions,variations of the anomalous absorption coefficient with the geomagnetic dip are calculated.It is shown that the coefficient increases with the geomagnetic dip until 70o,and then drops off slowly.With consideration of the geomagnetic field when calculating the HF conductivity,the coefficient is decreased and more obvious at high geomagnetic dip.%研究了电离层加热中的异常吸收效应.采用动力学理论,从弗拉索夫方程出发,结合磁化等离子体中电波色散关系与地磁场中泵波电场作用于电子与离子形成的位移电流,详细推导了加热形成的沿磁场分布电子密度不均匀体扰动所引起的电波幅度异常吸收系数.利用异常吸收系数解析表达式模拟计算了吸收系数随地磁倾角的变化,结果表明:随着地磁倾角的增加,异常吸收系数增大,在地磁倾角约70°以后缓慢下降;在考虑了地磁场对高频电导率影响后,异常吸收系数降低,而且地磁倾角越大系数下降越明显.