Spatial distribution of the auroral electron precipitations and the sources of field-aligned currents Original Research Article

Multiple inverted-V structures are commonly observed on the same auroral zone crossing by a low altitude orbiting satellite. They appear grouped and apparently result from an ionospheric and/or magnetospheric mechanism of stratification. AUREOL-3 satellite observations were analyzed to study their properties in the framework of the ionosphere-magnetosphere coupling model proposed by Tverskoy (1982). This model predicts some natural periodicity in the electrostatic potential profile in the order of 100–200 km at ionospheric altitudes that could account for oscillations experimentally observed in the auroral zone, such as successive inverted-Vs. These oscillations may naturally result when the initial pressure gradients needed to generate a large-scale field-aligned current have a sufficiently wide equatorial scale, of about 1 RE or more.