The shape of ionospheric irregularities in the auroral zone

Abstract

The evidence that ionospheric irregularities are elongated along the magnetic field is overwhelming. The actual extent of the elongation may, at least for mid-latitude locations, be considerably more than is usually quoted. Several years ago it was suggested that ionospheric irregularities, particularly at night in the auroral zone, are also elongated in the horizontal direction along the L shells. Since that time, there have been a number of investigations of this phenomenon, but there still seems to be some doubt about the actual degree of the anisotropy. This paper uses a limited number of navy navigation satellite system data from a high-latitude station (Sach's Harbour, N.W.T.) and a much more extensive HILAT satellite data set collected at Churchill, Man., to explore the question in a somewhat more direct, though statistically less definitive, way. The results give no clear support for the postulated L-shell extension.