磁爆期間在電離層中會出現兩類電場,分別稱為貫穿電場及擾動發電電場。貫穿電場可由高緯度地區傳遞到磁赤道地區,其強度及東西方向取決於太陽風中的行星際磁場。擾動發電電場在磁赤道的水平方向大致與安靜期的電場方向相反,亦即在白天是西向,在晚間是東向。擾動發電電場不同於貫穿電場,它須要幾個小時的時間來建立,形成以後,可持續幾個小時至一或二天的時間。有趣的問題出現且其成因至今不明而需要詳加研究的是,擾動發電電場並不是在每個磁爆期間都會出現。本研究計畫的主要目的即是了解及探索這個問題。主要的研究工具是全球電離層模式 TIEGCM (Thermosphere Ionosphere Electrodynamics General Circulation Model)。 Two electric fields appear in geomagnetic storms, i.e., prompt penetration electric fields and disturbance dynamo electric fields, respectively. The penetration electric field at the magnetic equator results from the high latitude with intensity and polarity determined by the interplanetary magnetic field (IMF) in the solar winds. The zonal disturbance dynamo electric field at the magnetic equator is almost opposite to that in the quiet time condition, namely, westward in the daytime and eastward in the night time. Compared with the penetration electric field, a few hours are required to set up the disturbance dynamo electric field, after which they can persist for several hours, even up to one or two days. An interesting problem that appears and requires more researches to explain is the disturbance dynamo electric fields do not always show up in the storm time. The purpose of this project is to understand and explore this interesting scientific problem. The main research tool in this project is the TIEGCM (Thermosphere Ionosphere Electrodynamics General Circulation model). 研究期間:9908 ~ 10007