Imaging the Perpendicular Plasma Dynamics Driving a Discrete Auroral Arc

Measurements of motions and structuring in auroral luminosity are combined with magnetically connected plasma measurements from the Reimei spacecraft to image the perpendicular plasma dynamics active above a discrete auroral arc. It is demonstrated how the inversion of optical flow patterns specifies the potential structure above regions of visible emission through monoenergetic or “inverted‐V” aurora. Connecting these structures with the observed morphology in luminosity returns the structure of the current, vector potential, perturbed magnetic field and Poynting flux powering the arc. These measurements connect perpendicular dynamics including flow shears and magnetic tearing to the energy transport and dissipation along the geomagnetic field that results in the formation of bright dynamic discrete aurorae.