Abstract

The relationship between the substorm expansion phase onset and the asymmetry of the latitudinal distribution of the upward field-aligned Region 1 current is studied. The dependence of the increment of the modified flute instability on the value and the direction of the field-aligned current is analyzed. The results of the auroral satellite Aureol-3 observations of electron precipitation in the time of the growth phase of the isolate substorm 1982.05.03 are presented. It is shown that the substorm brightening of the most equatorward auroral are can be related with the latitudinal asymmetry of upward field-aligned current.