Multiple Longitude Sector Storm‐Enhanced Density (SED) and Long‐Lasting Subauroral Polarization Stream (SAPS) During the 26–28 February 2023 Geomagnetic Storm

Abstract

AbstractThis paper conducts a multi‐instrument analysis and data assimilation study of midlatitude ionospheric disturbances over the European and North American longitude sectors during a strong geomagnetic storm on 26–28 February 2023. The study uses a set of ground‐based (GNSS receivers, ionosondes) observations, space‐borne (DMSP, GOLD) measurements, and a new TEC‐based ionospheric data assimilation system (TIDAS). We observed a series of distinct storm‐time features with regard to storm‐enhanced density (SED) and subauroral polarization stream (SAPS) as follows: (a) Under multiple ring current intensifications, the storm‐time subauroral ionosphere produced long‐lasting duskside SAPS for ∼36 hr along with considerable dawnside SAPS for several hours. (b) Associated with long‐lived SAPS, strong SED occurred consecutively in the European longitude sector near local noon during a positive ionospheric storm and later in the North American longitude sector near local dusk during a negative ionospheric storm. (c) The 3‐D morphology of SED in multiple longitude sectors was reconstructed using TIDAS data assimilation technique with fine‐scale details, which revealed a narrow ionospheric plasma channel with electron density enhancement and layer uplift.