The dynamics of midday auroras, including polar cusp and cap emissons, and their relation to the interplanetary magnetic field (IMF) have been investigated with optical ground-based observations from Svalbard (75¿ geomagnetic latitude), Norway, and IMF data from spacecraft ISEE 2. One case is presented, showing the spatial relationship- along the magnetic meridian in the midday sector-between the cusp aurora and IMF By-related convection currents (the DPY signature) for negative and positive values of IMF Bz.