Excitation and decay of magnetospheric lobe cell convection and its associated aurora

We discuss multi-instrument observations of the excitation and decay within a similar to 10 min interval of a convection pattern typical of lobe cells , centered at similar to 1230 MLT in the winter hemisphere. The plasma conv ection and its associated aurora were triggered by a rapid northward turnin g of the interplanetary magnetic field (IMF) monitored by near-Earth spacec raft. The IMF stayed northward oriented (B-x=-4 nT; B-y=2-3 nT; B-z=2-4 nT; clock angle=30 degrees-70 degrees) for 8 min, before rotating back south. The optical instruments recorded the activation of an east-west aligned aur oral form near the latitude of the pre-existing cusp aurora at similar to 7 3 degrees MLAT, which was followed by a smooth, 10-min long poleward advanc e at an average speed of 0.4 km s(-1), reaching 75 degrees MLAT at its most expanded phase. Simultaneous CUTLASS radar and local magnetic data confirm the occurrence of a large reconfiguration of plasma convection involving a change from antisunward to sunward flow components in the vicinity of the cusp, consistent with the presence of a lobe cell.