低纬地区夜间电离层底部电子浓度与磁扰的关系

THE RELATIONSHIP BETWEEN THE NIGHTTIME ELECTRON DENSITY IN THE LOWER IONOSPHERE AT LOW LATITUDES AND MAGNETIC DISTURBANCES

本文利用100 kHz的低频无线电波资料,计算分析了1986—1987年期间,几种不同磁扰情况下,低纬地区夜间电离层中100km以下区域积分电子浓度及其变化的起因.结果表明:该区域电子浓度的变化与地磁扰动关系密切.在磁静日期间,其值较小,且随磁扰而变化,但比磁扰滞后1到2天.在磁暴后,其值较大,会出现几次剧烈起伏.该区域积分电子浓度的起伏可大于一个量级.

Using the data of 100 kHz low frequency radio wave (Loran-C signal), the nighttime integral electron density in the ionosphere below 100 km at low latitude are calculated, and the cause of this variations are analyzed under various magnetic disturbances during 1986-1987.The results show: In the lower ionosphere at low latitudes, the nighttime variations of electron density are related to geomagnetic disturbances. The electron density are smaller, and changing following geomagnetic disturbance in one or two days during geomagnetic quiet days. The electron density are larger during and after magnetic storms. The fluctuation of the integral electron density in this region can be one order greater, it reaches peak value in 2-3 days after a magnetic storm. The bremsstrahlung radiation produced by the precipitating electrons may be a main factor which causes the nighttime variations of electron density in the lower ionosphere at low latitudes.