Influence of Atmospheric Circulation on Orientation of Auroral Arcs

Abstract

The first systematic studies of the morphology of aurorae were undertaken during the International Geophysical Year in [1957][1958] and resulted in the discovery of the auroral oval (e.g., . Specifically these systematic studies demonstrated that bright aurorae appear within an oval-shaped belt surrounding the geomagnetic pole at geomagnetic latitudes between 60° and 80°, dependent on geomagnetic activity. The most prominent auroral forms populating the auroral oval are relatively narrow multiple auroral arcs extended for many hundred kilometers within the oval and drifting in the north-south direction. In the 1960s a number of studies were devoted to the morphology of the auroral arcs, including their orientation (Feldstein et al., 2014, and references therein). These studies were based on optical observations from the ground. Subsequently, electric field and currents pattern associated with auroral arcs were derived from rocket (Marklund, 1984), radar (Aikio et al., 2002), and satellite (Marklund et al., 2001 observations. Satellite observations allowed the investigation of the characteristics of the electron precipitation producing the auroral luminosity and identification of the magnetospheric plasma domains associated with the aurorae (Newell et al., 2004). On the basis of these experimental data there were more than 20 hypotheses and models suggested to explain the origin of the auroral arcs (Borovsky, 1993), although, to our knowledge, no widely accepted comprehensive theory exists so far to explain the generation of auroral arcs in a satisfactory way.