Behaviors of ionospheric topside ion density, ion temperature, and electron temperature during the 20 November 2003 superstorm

We identified a few new storm-time ionospheric phenomena by analyzing disturbances in topside ion density, electron temperature, and ion temperature at similar to 840 km altitude measured by the Defense Meteorological Satellite Program satellites during the 20 November 2003 magnetic storm. The storm-time ion density enhancements showed different features at different local times. Longitudinal structures in the enhanced ion density occurred in the morning sector and extended from equatorial regions to middle latitudes. Ion density increase due to enhanced fountain effect was observed in the evening sector and lasted for similar to 18 hr. A positive ionospheric storm occurred during the late recovery phase of the storm and was associated with increased atomic oxygen to molecular nitrogen column density ratio. Electron temperature at subauroral latitudes reached 8000 K during the storm, similar to 4000 K higher than the quiet-time temperature. The subauroral temperature enhancement lasted for 2-3 days. Simultaneous enhancements in the ion density, electron temperature, and ion temperature from subauroral to equatorial latitudes occurred in the night-time ionosphere and lasted for similar to 18 hr. A negative correlation between ion density and electron/ion temperature variations occurred in the dusk sector for similar to 12 hr. An enhanced ion temperature crest in the winter hemisphere during the magnetic storm lasted for 2 days. A decrease in the ion temperature crest was also observed with an increase of the ion density. These new features in the ionospheric density and temperature, together with the results from previous studies, provide a more comprehensive scenario of the ionospheric response to the superstorm.