Local time variations of auroral electrojet during storm time: DMSP and CHAMP coordinated observations

The auroral electrojet plays an important role in the ionosphere-magnetosphere coupling progress. Based on ten years of DMSP and CHAMP coordinated observations, we investigate the local time variations of the auroral electrojets during storm periods. The results show that the auroral electrojets respond obviously to the sudden change of solar wind inputs (merging electric field, substorm, and interplanetary shock) in all local time. The local time asymmetry of the response time and strength of the electrojets to these three types of disturbances are investigated. The auroral electrojets respond to the shock faster than the sudden change of merging electric field. The disturbed auroral electrojet strength peaks at different local times during different kinds of solar wind input events. The different features of eastward and westward electrojets during storm periods are studied during the disturbance periods. The physical mechanisms for the local time variations of auroral electrojets in response to the disturbance are discussed in detail.