电离密度分布对中低纬非导管哨声波传播的影响

EFFECTS OF THE IONIZATION DENSITY DISTRIBUTION ON NON-DUCTED WHISTLER WAVE PROPAGATION AT MIDDLE AND LOW LATITUDES

本文在偶极子地磁模型和各种电离密度分布模型中,对中低纬非导管哨声波的传播特性进行了射线追踪研究。结果表明,地磁场位形及其引起的磁层等离子体的各向异性是决定哨声射线几何特征及速度结构的主要因素,而电离密度仅在一定程度上改变上述特征;电离层是形成哨声射线聚焦的主要原因;赤道异常和电离层显著地影响哨声波的到达纬度;哨声群时延和色散值主要决定于电离密度;中低纬非导管哨声近似符合Eckersley定律;电离层是决定波法线角能否满足透射条件的主要因素。

Propagation characteristics of non-ducted whistler wave at middle and low latitudes have been studied by means of ray-tracing method for dipole magnetic field and several ionization distribution models.The results show that the configuration of the geomagnetic field and resultant plasma anisotropy are governing factors which the geometric features of whistler ray and velocity structure of whistler wave depend on,while ionization density may change,to some extent,these features.The ionosphere is the major cause of whistler ray focusing.The equatorial anomaly and the ionosphere greatly affect the arrival latitude of whistler wave at middle and low latitudes.The group delay and dispersion of whistler wave are mainly dependent on ionization density.Non-ducted whistler follows Eckerslep law.The ionosphere is a principal factor determining whether or not the wave normal angle satisfies transmission condition through the ionosphere.