Enhanced antisunward convection and F region scintillations at mid‐latitudes during storm onset

Abstract

Millstone Hill radar observations over a wide span of latitudes detail the onset of 300 m/s antisunward (westward) convection at mid and low latitudes in the morning sector as a region of storm‐enhanced sunward convection retreats poleward. Ring current observations reported by Lui et al. (1987) suggest that the magnetospheric shielding layer was coincident with the observed reversal between sunward and antisunward convection. A strong southward component of the F region neutral wind is observed at latitudes equatorward of the convection reversal. These observations are in agreement with the model of Spiro et al. (1988), who find that storm‐enhanced neutral winds at latitudes equatorward of the shielding layer can generate a long‐lived perturbation electric field in the inner magnetosphere. Our observations show the growth of the subauroral electric field as the shielding boundary moves poleward. We observe 136‐MHz scintillations in both the auroral sunward convection region and the region of subauroral antisunward convection when the convection electric fields exceed 5 mV/m.