The roles of static and dynamic electric fields in the auroral acceleration region

Charged particles and electric fields measured by the Fast Auroral Snapshot satellite (FAST) are being widely interpreted as final vindication of the theory that the electrons responsible for the brightest and most highly structured forms of aurora gain their energy by being accelerated in static electric fields. However, measurements of electrostatic waves from the same satellite also give further impetus to the opposing theory that the electrons are energized by the dynamic electric fields of plasma waves. Consideration of the different capabilities of static and dynamic electric fields leads to a model of the auroral electron acceleration region incorporating acceleration by both types of fields. An experimental test of the model is suggested.