Geomagnetic Variation and Field-Aligned Currents at Northern High-Latitudes, and their Relations to the Solar Wind Parameters

By using statistical analysis to study the relation between the interplanetary and geomagnetic fields, geomagnetic variations have been detected that are controlled by different parameters of the solar wind. The equivalent current systems for these geomagnetic variations have been determined for the 1968 summer and winter seasons from data from 14 high latitude stations. It has been shown that the geomagnetic field at high latitudes ($\Phi \geq $ 60 degrees) can be represented by a sum of fields controlled by components of the Interplanetary Magnetic Field (I.M.F.) and by the velocity and density of the solar wind plasma. A correlation model is proposed by means of which hourly-mean values of the three components (X, Y, Z) of the geomagnetic field vector at high latitudes may be determined from hourly-mean values of the components B$_{x}$, B$_{y}$ and B$_{z}$ of the I.M.F. The space--time distribution of field-aligned currents has been reconstructed from the horizontal component of the ground level geomagnetic field variation. The correlation model of field-aligned currents has been obtained for high latitudes ($\Phi \geq $ 60 degrees). According to the model the value and direction of the field-aligned current j$_{\parallel}$ are determined by I.M.F. components and spatial coordinates. The proposed model of field-aligned currents enables the nature of the actual magnetic disturbance registered during a given pass of the TRIAD and ISIS-2 satellites through the high latitude region to be interpreted. Moreover it enables some discrepancies between observations and the models of field-aligned currents proposed in the literature to be understood.