Multiplatform Investigation of the Role of Wave Accelerated Electrons in Magnetospheric Processes

Intense fluxes of wave accelerated low energy electrons in auroras signify the location of large scale energy input from the magnetosphere. Studying these wave accelerated electron (WAE) auroras require the monitoring of the auroral dynamics by high resolution (ground- or space-based) imaging while simultaneously measuring the particles at various altitudes to determine the characteristic electron spectrum and to observe the transition of wave Poynting flux into electron energy. This wave acceleration is another distinct and presumably transient process by which magnetic energy of the magnetosphere is converted into particle (electron) energy and transmitted into the atmosphere in the form of auroral electrons. Using the FAST satellite and auroral imaging from the IMAGE spacecraft we were able to show that prior to substorm onset WAE auroras occur infrequently and mostly near the poleward boundary of the auroral oval, presumably near the boundary of open and closed field lines, where steady state reconnection is expected to occur. At onset WAE electrons play a primary role in the surge formation and the break up aurora. This aurora is located deep in the region of closed field lines. After onset the poleward propagating auroral surge consists of WAE electrons at the poleward edge of the closed field configuration and is closely followed by inverted V type precipitation. The ground based auroral imaging operating simultaneously with the future THEMIS satellites will have better spatial resolution for the investigation of the aurora associated with these processes.