用简单模式法对高纬电离层电场的进一步研究

本文采用的是有二区场向电流但无电导率时角变化的简单模式。文章通过模式计算,系统讨论了在恒稳条件下二区场向电流强度及位相和Hall与Pederson电导率在极光带升高等因素对高纬电场分布的影响。模式说明,二区场向电流的存在使二区电流圈以内电场加强,其外电场大大削弱。这种加强与削弱作用与二区电流的强度与位相均有关。Hall电导率在极光区升高会加强上述作用,Pederson电导率的升高则对其有所削弱。一般说来,极盖区外电场分布的位相与极盖区边界的驱动势不同,一、二区场向电流的位相与驱动势也有差异。这些现象都是场向电流与电导率共同影响的结果。以下结果初步解释了近年来的某些观测现象。最后,本文对简单模式法的应用及今后的某些方向作了探讨。

A FURTHER EXPLORATION OF ELECTRIC FIELD IN THEHIGH-LATITUDE IONOSPHERE BY USINGTHE SIMPLE MODEL METHOD

The simple model, in which the region 2 field-aligned currents and the enhancement of the conductivities in the auroral zone are taken into account but the local time dependence of the conductivities is omitted, is constructed to make an exploration of the high-latitude E-fields. It is shown that E-fields are strengthened by the region 2 field-aligned currents within the area between the polar cap boundary and the currents circle but depressed outside it; the effects are controlled by both the intensity and the phase of the currents. The shielding caused by the enhancement of ∑H in auroral zone will strengthen the effects, but the enhancement of ∑p, however, will largely weaken them and the E-field will penetrate into the middle latitude. Generally the phase, of the potential distribution outside the polar cap is different from that of the driving potential at the polar cap, and so are the phases of the region 1 and 2 field-aligned currents. They are summing-up effects of all the factors mentioned above. The potentiality of the simple model method and the possible direction of its development are also discussed.