Characteristics of field-aligned currents deduced from preliminary data analysis of MAGSAT observations

Preliminary analyses of the MAGSAT magnetic field data have been carried out. In high latitudes the signatures of field-aligned currents are clearly recognized to have the following characteristics : (1) the persistent basic pattern of current flow (so-called Regions 1 and 2), with the dominate in intensity of Region 1 (pole-side) current over Region 2 (equator-side) current, and with greater variability of Region 2 current presumably depending on the substorm activity; (2) spatial latitudinal extent of field-aligned current being about 3°for Region 1 and about 5° for Region 2,wider than previously expected, and unusual reverse polarity of current flow direction; and (3) apparent dawn-dusk asymmetry in the field-aligned current intensity between the north and south polar regions