The geotail and ring current dynamics under disturbed conditions

Abstract

Complex study of satellite and ground-based data as well as theoretical modelling has been carried out to estimate the roles of different magnetospheric sources of geomagnetic disturbances. The geotail and ring current dynamics during the magnetic storm on 23–27 November 1986 were calculated using the dynamic paraboloid model of the magnetospheric magnetic field. The solar wind data and magnetospheric indices were used to calculate the time-dependent paraboloid model parameters. The auroral oval boundaries were determined using the DMSP electron fluxes precipitation data. The ring current magnetic field was calculated using data from AMPTE/CCE measurements of the ring current energetic ion fluxes. The comparison of the model calculations with Dst and GOES-6 satellite data was carried out. It was found that magnetopause currents’, ring current's and tail current's contributions to Dst are of about the same order of magnitude in the course of the magnetic storm on 23–27 November 1986. The energy stored in the tail correlates strongly with the power delivered from the solar wind to the magnetosphere. The total energy of the ring current particles increases when the interplanetary magnetic field is southward. Ring current growth stops during periods of high auroral activity.