Аннотация:Interplanetary shocks which are observed in the solar wind can cause sudden changes of magnetic field observed at ground-based stations. The observed sudden changes, called sudden commencements, differ for different stations at different magnetic latitudes and local times. The main objective of this work is to identify the relationship between the impact angles of the interplanetary shocks on the resulting sudden commencement impulses, measured by ground-based magnetometers. For this purpose, an open database of interplanetary shocks (Oliveira, 2023) with shock front normal directions defined for each case and magnetic indices from the SuperMAG database (Newell, Gjerloev, 2012) is used, which, unlike the traditionally considered SYM-H and Dst indices, allow one to consider geomagnetic field variations for different local times. We have found out that in most of the cases considered, the SC impulse in the dusk sector exceeded the SC impulse in the dawn sector, despite the approximately uniform distribution of the interplanetary shock impact angles. This effect can be described by the influence of ionospheric currents. However, it has been shown that for very large angles of shock impact arriving from dawn side, the SC amplitude in the dawn sector may exceed the SC amplitude in the dusk sector, which can be described by the effect of currents on compressed magnetopause.
