研究期間：10108~10207;Two electric fields often 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, maximum magnitude occurring at LT04~LT05. Compared with the penetration electric field, the disturbance dynamo electric field requires a few hours to build up, after which it can persists for several hours, even up to one or two days. An interesting problem appearing and requiring more researches to explore is that the disturbance dynamo electric fields do not always show up in the storm time. Based on the preliminary results of the previous project, the purpose of this project extends to further understand and explore the exact mechanism behind this interesting scientific problem. The main research tool used in this project is the TIEGCM (Thermosphere Ionosphere Electrodynamics General Circulation model). The preliminary results show that angular offsets, between geographic and geomagnetic axes, and seasonal effects have a strong effect on the magnitudes of the disturbance dynamo electric fields. This project is to validate and verify this mechanism using the TIEGCM and ROCSAT-1 data.
