Studies On Correlative Problems Of Geomagnetic Activities

Geomagnetic activity with the global effect is a very important phenomenon in the space weather, and is the significant section of the solar wind-magnetospheric coupling process. The magnetopause is arguably the most critical boundary of the magnetosphere, and can protect our earth and human from injuring by energetic particles. Meanwhile, the magnetopause location can respond to the upstream changes dynamically, and impact the internal responses of the magnetopause. In this thesis, the correlation between magnetopause location and geomagnetic activities is discussed, and the results would contribute to understand the solar wind-magnetospheric coupling process. Moreover, the technology of coalescing upstream solar wind observation data can be beneficial to understand solar wind states and forecast magnetic storm activity, and it is very significant in practice to study geomagnetic activities.In the thesis, the research contents are as follow:1. With the solar wind data observed by ACE/WIND spacecraft and geomagnetic storm Dst index data during 2004-2006, the linear correlation between magnetopause standard off distance Ro and Dst index described the grade of geomagnetic storm is investigated in terms of 200 different graded storms. The analysis illustrate that time series of Dst index is lagged about 3 hours than the magnetopause standard off distance Ro calculated by C02 Model under extreme solar wind. Corrected the lag time, the results are obtained as follow:the linear correlation coefficients average values are 0.77,0.74,0.47and 0.24 respectively, corresponding to the super, the big, the middle and the little storms. Finally, under different graded storms, the charts of Ro-Dst fitted by the least square method are shown.2. We examined the effect of magnetopause dayside location of earth on the generation of magnetospheric substorm. Based on the C02 model, the linear regression analysis illustrate that the correlation between AL/AE index and magnetopause standard off distance R0 is obvious when substorms occur. Especially, the correlation between AE index and R0 when substorms with all storms occurred is better than the correlation when substorms without storms occurred.3. In this thesis, a scheme is proposed for coalescing upstream solar wind observation data in order to forecast magnetic storm activity more accurate. That is to say, this thesis presents a concept of the Least Squares about solar wind and IMF data which come from spacecrafts ACE, IMP8 and WIND. With a typical geomagnetic storm, the predicted Dst accuracy using the multi-spacecrafts upstream solar wind coalesced data taken advantage of the Least Squares method is increased to 51.15% from 41.6%, based on Lund Dst model. So the coalesced method with the multi-spacecrafts upstream solar wind data can make for understanding the magnetosphere environment.