Modeling the spatial structure of the high latitude magnetic perturbationsand the related current systems

Previous input-output analysis of the electrojet indices has been generaliz ed to a spatio-temporal dynamical model of the high latitude magnetic pertu rbation (HLMP) by using the spatially dependent measurements that can be pr ovided by a ground magnetometer array of latitudinal coverage. A technique that utilizes the daily rotation of the Earth as a longitudinal, or local t ime, sampling mechanism is used to construct a two-dimensional representati on of the high latitude magnetic perturbations, both in magnetic latitude a nd local time, from the single latitudinal chain of magnetometers. Two-dime nsional static, linear dynamical and nonlinear dynamical models for the evo lution of the spatial structure of the HLMP are constructed by including a coupling to the solar wind as the energy input. The nonlinear spatial model of the HLMP produces better predictions than the linear one, reducing the average error from 65 to 50 nT for the H-x component. This can be taken as an indication that during intense activity, the HLMP and related current sy stem evolves in a nonlinear fashion. (C) 1999 American Institute of Physics . [S1070-664X(99)03211-5].