Localized Aurora beyond the Auroral Oval

Harald Frey (SSL)

Over the past few years our knowledge about auroral physics has been greatly enhanced by information taken from space-based ultraviolet imaging. The Polar-UVI and IMAGE-FUV instruments provided long-duration, global observations of the aurora, their spatial distribution, and temporal behavior. In addition to the well-known auroral oval, many localized auroral features have been discovered or better described that are either embedded in the auroral oval, or clearly separated from it towards higher or lower magnetic latitudes. The major features are sub-auroral proton flashes or patches at noon, the cusp aurora with very different morphology during northward and southward IMF, high latitude dayside aurora (HiLDA), the 1500 MLT hot spot, detached afternoon auroral arcs, sub-auroral morning proton spots (SAMPS), evening co-rotating patches, and auroral streamers.

Some of these features occur during quiet, others during disturbed geomagnetic conditions. Some of the phenomena are triggered by specific external solar wind conditions, others appear to be the result of internal magnetospheric processes. This presentation will summarize all these individual phenomena, discuss their physical origin as far as we understand it now, and will give suggestions for future research directions.