Birkeland current boundary flows

Abstract Intense zonal ion velocity jets in the northern nightside auroral zone are measured during quiet geomagnetic conditions by the Swarm satellites around 500 km altitude. These velocity jets, exceeding 1 km/s in over 50% of orbits measured, range from 20 to 100 km in meridional thickness and reach a maximum at the boundary between upward and downward field‐aligned current. On average they represent a potential difference of approximately …