Relationship between field‐aligned currents, diffuse auroral precipitation and the westward electrojet in the early morning sector

Abstract

On the basis of Chatanika radar data and simultaneous Triad satellite data, the relationships between field‐aligned currents, diffuse aurora, electric fields, and currents in the early morning sector are examined. The diffuse aurora is coincident with the upward region 2 field‐aligned current. Within the upward region 2 field‐aligned current, small‐scale current structures are often present. These structures seem to coincide with small‐scale electron density enhancements in the E region, which are probably produced by energetic electron precipitation. The westward electrojet extends across the region 2/region 1 boundary in the morning sector. The southward electric field is large at and poleward of this boundary. It is most probable that the region 2 field‐aligned currents are closed by southward Pedersen currents within the ionosphere.