初始波法线角对中低纬非导管哨声波传播的影响

EFFECTS OF INITIAL WAVE NORMAL ANGLE ON PROPAGATION OF NON-DUCTED WHISTLER WAVE AT MID AND LOW LATITUDES

本文对初始波法线角δ_s不同的中低纬非导管哨声进行了射线追踪研究,结果表明,当δ_s≤0°时,哨声波可到达较大的L值,在另一半球较高纬度处形成“聚焦区”,这组哨声色散值较大;当δ_s>0°时,随以的增加,哨声射线内移,δ_s>10°的哨声射线汇聚于另一半球较低纬度处,这组哨声色散值较小。据此提出解释中低纬哨声色散值连续变化的一种可能机制:电离层电子浓度水平梯度的连续变化引起初始波法线角以的连续变化,从而导致射线路径、群时延和色散值的变化。

Propagation of non-ducted whistler wave at mid and low latitudes has been studied for different initial wave normal angle δs by means of ray-tracing technique. The results show that in case of δs≤0° whistler waves will propagate into the region with larger L values, and converge to a relatively narrow latitude belt with higher latitudes in another hemisphere, and this group of whistler waves has larger dispersion; when δs>0°, whistler rays will move inward, and converge to lower latitudes in another hamisphere and when δs>10°, this group of whistler waves has smoller dispersion. On the basis of above-mentioned characteristics, a possible mechanism is proposed for explaining continuous variation of whistler dispersion.