Dependence of longitudinal localization of substorm center on geosynchronous orbits on the IMF Bγ-component

The dependence of the longitudinal substorm center localisation on geosynchronous orbits on the IMF Bγ-component has been studied. It is shown that the local magnetic time of the longitudinal substorm center localisation in the magnetosphere varies from evening hours to morning hours as the Bγ-component increases. At low solar wind speeds the substorm centers localize nearer to the evening sector. The ionospheric projection of the substorm center magnetospheric localisation shifts westward at By<0 and eastward at By>0. Maximum longitudinal shifts of substorm centers in the ionosphere relative to their location in the magnetosphere are - 3.5 h at Bγ=-4 nT and 3.5 h at Bγ=4.4 nT. Thus, the change of the substorm center localisation relative to the midnight in the ionosphere is caused by both the change of the substorm center position in the magnetosphere and a turn of the magnetotail relative to X-axis.