Dayside Aurora Dynamics

Images from the FUV instrument on board the IMAGE spacecraft will be presented to demonstrate the auroral dynamics in the dayside auroral zone and the polar cap region. Optical emissions detected by three different detectors of FUV come from precipitations of energetic protons, electrons, and both species, respectively. In general, auroral activities in these regions responded very well to variations in the boundary conditions either external or internal to the magnetosphere, i.e., in the solar wind or the magnetotail. As a result, auroral images from FUV provide an excellent tool to investigate particle acceleration and transport processes within the geospace, such as shock acceleration, substorm injections, etc. We will interpret the observed auroral images using various models, discuss difference and similarity in the auroral activity from several typical cases, and assess conditions optimal to each type of auroral activity.