Modelling of the magnetic field of magnetospheric ring current as a function of interplanetary medium parameters

Abstract

The models are examined which are proposed elsewhere for describing the magnetic field dynamics in ring-currentDR during magnetic storms on the basis of the magnetospheric energy balance equation. The equation parameters, the functions of injectionF and decay τ, are assumed to depend on interplanetary medium parameters (F and τ during the storm main phase) and on ring-current intensity (τ during the recovery phase). The present-day models are shown to be able of describing theDR variations to within a good accuracy (the r.m.s. deviation 5 <δ < 15 nT, the correlation coefficient 0.85 <r < 1). The models describe a fraction of the geomagnetic field variation during a magnetic storm controlled by the geoeffective characteristic of interplanetary medium and, therefore responds directly to the variation of the latter. The fraction forms the basis of the geomagnetic field variations in low and middle latitudes. The shorter-term variations ofDR are affected by the injections into the inner magnetosphere during substorm intervals.