Modeling of geomagnetic field during magnetic storms and comparison with observations

This paper discusses: (a) development of the dynamic paraboloid magnetosphe ric field model. (b) application of this model for the evaluation of a vari ety of magnetospheric current systems and their contribution to the ground magnetic field variations during magnetic storms, (c) investigation of auro ral electrojet dynamics and behavior of plasma precipitation boundaries. an d (d) usage of the paraboloid magnetospheric field model for revealing rela tionships between geomagnetic phenomena at low altitudes and the large-scal e magnetospheric plasma domains. The model's input parameters are determine d by the solar wind plasma velocity and density, the IMF strength and direc tion. the tail lobe magnetic Aux F-infinity, and the total energy of ring c urrent particles. The auroral particle precipitation boundaries are determi ned from. the DMSP particle observations: these boundaries are used to calc ulate the value of F-infinity. The influence of the field-aligned tail, and ring currents on the magnetospheric field structure is studied. it is foun d that the polar cap area is strongly controlled by the tail current. The p araboloid magnetospheric field model is utilized for the mapping of the aur oral electrojet centerlines and boundaries into the magnetosphere, Analysis of the magnetic field variations during magnetic storms shows that the con tributions: of the ring current, tail current, and the magnetopause current s to the D-st variation are approximately equal. (C) 2001 Elsevier Science Ltd. All rights reserved.