Multipoint Observations of an Active Auroral Arc by a Sub-Orbital Sounding Rocket Mission

The NASA Auroral Spatial Structures Probe, 49.002, was launched January 28, 2015 from the Poker Flat Research Range into active aurora over the northern coast of Alaska. Six small payloads were ejected from the main payload to form an ordered constellation to observe the aurora. The payloads encountered the breakup of an auroral arc when they were spaced in the range of 2.5 to 6 km apart from each other. Observations were made of electric and magnetic fields at each payload and ground based imagers captured the position of the visible aurora relative to this small constellation. Five of the payloads traced the same ground track observing the same flux tube region over time. The objective of this constellation was to resolve the spatial and temporal observations of electric and magnetic fields that exist on the scales of the auroral arc. We were surprised at the amount a variability observed over the sampled temporal and spatial scales. We present results from the magnetic and electric field instruments and discuss the small scale fluctuations in time and space associated with an active auroral arc. The field aligned currents and Poynting flux derived from the observations are shown and implications are discussed in terms of the contribution of small spatial scale, rapid temporal scale fluctuations in the currents that deposit energy in the auroral region.