Dayside equatorial‐plane convection and IMF sector structure

Using 1290 hours of GEOS‐2 electron gun measurements between 0800 LT and 1900 LT we have analyzed the dependence of dayside magnetospheric convection in the equatorial plane at L = 6.6 RE on the IMF sector structure, i.e. IMF By ≷ 0 and IMF Bx ≷ 0. For all IMF sector orientations the plasma flow at noon is directed predominantly sunward with a slight dawnward component. For positive IMF By the plasma convection around 0900 LT has a duskward component which turns into a dawnward component for negative IMF By values. The ratio between the electric field amplitudes at 1500 LT (dusk sector) and those at 0900 LT (dawn sector) increases from about 2 for IMF By positive to 3–4 for negative IMF By components. The convection pattern does neither show a dependence on the Bx component of the IMF nor is it significantly different for gardenhose (Bx · By < 0) and nongardenhose (Bx · By > 0) orientations of the IMF. These results support the idea of component merging rather than the antiparallel merging hypothesis.