Modeling of geomagnetic field during magnetic storms and comparison with observations

Abstract

This paper discusses: (a) development of the dynamic paraboloid magnetospheric field model, (b) application of this model for the evaluation of a variety of magnetospheric current systems and their contribution to the ground magnetic field variations during magnetic storms, (c) investigation of auroral electrojet dynamics and behavior of plasma precipitation boundaries, and (d) usage of the paraboloid magnetospheric field model for revealing relationships between geomagnetic phenomena at low altitudes and the large-scale magnetospheric plasma domains. The model's input parameters are determined by the solar wind plasma velocity and density, the IMF strength and direction, the tail lobe magnetic flux F ∞, and the total energy of ring current particles. The auroral particle precipitation boundaries are determined from, the DMSP particle observations; these boundaries are used to calculate the value of F ∞. The influence of the field-aligned tail, and ring currents on the magnetospheric field structure is studied. It is found that the polar cap area is strongly controlled by the tail current. The paraboloid magnetospheric field model is utilized for the mapping of the auroral electrojet centerlines and boundaries into the magnetosphere. Analysis of the magnetic field variations during magnetic storms shows that the contributions of the ring current, tail current, and the magnetopause currents to the D st variation are approximately equal.