Flickering aurora -
The possible importance of electric field shear
Flickering aurora can be seen in bright homogeneous arcs as a roughly 10 Hz modulation in the auroral intensity. This modulation normally fills a spot 5-10 km transverse to the magnetic field line. The flickering dies away within a few minutes, and reappears along the arc in another location. In this talk I will review the history of flickering aurora, and show how the use of high speed photometers have revealed new information about flickering aurora. I will also discuss the possible importance of inhomogeneous energy-density driven (IEDD) waves caused by electric field shear in understanding these new observations.