Dependence of the Postnoon Auroral Intensity upon the IMF Parameters

Abstract

AbstractBased on auroral observations with a multi‐channel scanning photometer at Zhongshan Station, Antarctica and interplanetary magnetic field (IMF) data obtained by WIND Satellite at the upstream of the bow shock in 1997 and 1998, the dependence of the high‐latitude postnoon auroral intensity upon the IMF components and clock angle are studied. It is shown that the 630 nm intensity depends on the IMF more directly than the 557.7nm does. The 630nm intensity decreases as the IMF Bx increasing with a correlation coefficient of ‐0.83, while the dependence of 557.7nm on IMF Bx is not so close. The auroral intensity (both 630nm and 557.7 nm) varies with the IMF By as a “V” shape, having a minimum at By=‐3 nT; while it varies with Bz as a lain “Z” shape, having two turning points at Bz=‐3 nT and Bz=2 nT respectively. The correlation coefficient between the 630nm intensity and the IMF total intensity B is 0.89, while the correlation between the 557.7nm intensity and the IMF B seems not so good. The auroral intensity varies with the IMF clock angle with an inverse “V” structure that turns at θ = 130°.