Место издания:Copernicus Gesellschaft mbH Göttingen
Аннотация:On the base of DMSP data the magnetotail current contribution to Dst in the course of the magnetospheric disturbance on January 9-12, 1997 was calculated. The analy- sis of the magnetic disturbance in terms of paraboloid (A2000) model shows that in the course of the main phase of the magnetic storm the contribution of the magne- totail is about of -60 nT and approximately equal to Dst by an order of magnitude in accordance with [Alexeev et al., 2001]. In [Turner et al., 2000] this value was cal- culated by T96 model and obtained as about of -22 nT at the storm maximum. To understand whether these results contradict one other or not we must reach agreement about the concept "contribution to Dst". It is shown that the term "tail current con- tribution to Dst" has the different sense in [Turner et al., 2000] and [Alexeev et al., 2001]. Actually, the both investigations give the similar results during the storm max- imum. The comparative analysis of the magnetic field dynamics calculated in terms of T96 and A2000 models during January 9-12, 1997 shows that both the models give the good agreement during the quiet periods when all the current systems change synchronously. However, during the disturbed periods the magnetic field dynamics obtained by T96 and A2000 models are often different. There are the periods when magnetospheric current systems change nonsynchronously with its own time scale. Sometimes, depending on parameters originated from both solar wind and magne- tosphere one of these current systems becomes dominant. It was shown in terms of A2000 that the intense Dst positive enhancement (up to +50 nT) in the course of the magnetic storm recovery phase in the first hours on January 11, 1997 is associated with a significant increase of the currents on the magnetopause, while the ring current and the magnetotail current remain at a quiet level.