The geotail and ring current dynamics under disturbed conditions

Complex study of satellite and ground-based data as well as theoretical mod elling has been carried out to estimate the roles of different magnetospher ic sources of geomagnetic disturbances. The geotail and ring current dynami cs during the magnetic storm on 23-27 November 1986 were calculated using t he dynamic paraboloid model of the magnetospheric magnetic field. The solar wind data and magnetospheric indices were used to calculate the time-depen dent paraboloid model parameters. The auroral oval boundaries were determin ed using the DMSP electron fluxes precipitation data. The ring current magn etic field was calculated using data from AMPTE/CCE measurements of the rin g current energetic ion fluxes. The comparison of the model calculations wi th Dst and GOES-6 satellite data was carried out. It was found that magneto pause 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 o n 23-27 November 1986. The energy stored in the tail correlates strongly wi th the power delivered from the solar wind to the magnetosphere. The total energy of the ring current particles increases when the interplanetary magn etic field is southward. Ring current growth stops during periods of high a uroral activity. (C) 2001 Elsevier Science Ltd. All rights reserved.