Characteristics and Spatial-Temporal Variations of the Ionosphere from Subauroral to Equatorial Latitudes during a Space Weather Event

We have analyzed ionospheric measurements of the Defense Meteorological Satellite Program (DMSP) satellites during an intense magnetic storm and identified the following phenomena. Strong penetration electric fields cause large vertical ion drifts over the magnetic equator, subauroral polarization streams (SAPS) penetrate to the equatorial latitudes and cause large westward ion drifts, the topside ion density at middle latitudes is enhanced by an order of magnitude for 12 hours or longer, and the electron temperature at subauroral latitudes is enhanced by 1,000-4,000 K over a few days. This study provides new insight into the characteristics and spatial-temporal evolution of ionospheric space weather processes.