磁暴期内中低纬电离层扰动实例分析

A Case Study of the Ionospheric Disturbance During a Magnetic Storm in Low and Mid-latitude Regions

用四个经度链附近电离层垂测资料，分析1986年2月6－10日磁暴期间的电离层扰动现象。磁层－电离层间电动耦合的东向电场是造成多站f0F2同时突增的主要机制。扰动的赤道电集流使'喷泉效应'增强对赤道异常驼峰区f0F2增高也起重要作用。磁暴后期，电离层扰动发电机电流系在低纬区的西向电流、电场使F层电子密度下降，而赤道区'喷泉效应'减弱的结果则是驼峰区各站f0F2明显下降的原因。

Global features of the ionospheric disturbance during a magnetic storm on 7-9 Feb., 1986 are analyzed by using ionosonde data from stations distributed nearby 4 meridian chains. The main mechanism, which leads to the simultaneously sudden enhancement of multi-stationally observed f0F2, is proposed to be the eastward electric field produced by the magnetosphere- ionospheric electrodynamic coupling. The enhancement of the 'fountain effect' which caused by the disturbed equatorial electrojet , also takes an important role to the increase of f0F2 at disturbed period in the bierest of the equatorial anomaly region. During the later period of a magnetic storm, westward electric current and field in lower latitudes prepuced by the ionospheric disturbance dynamo will decrease the electron density in F-region. On the other hand, the weakenning of 'fountain effect' may reduce the value of f0F2 observed in the crest area.