Prompt thermospheric response to the 6 November 2001 magnetic storm

[1] Thermospheric densities observed by the STAR accelerometer on CHAMP, near 400 km altitude, are used to examine the response to the major geomagnetic storm on 6 November 2001. This is the first large storm studied with CHAMP data at these near dawn-dusk local times. New features of the neutral density response at both global and local temporal/spatial scales have been revealed. Prompt response of the neutral atmosphere observed at the beginning of the storm was enriched by short- and meso-scale perturbations. Simultaneous observations of electromagnetic and ionospheric plasma perturbations and particle precipitations from the DMSP satellites, electron energy fluxes from NOAA-14 and Polar/UVI specified the energy source and the time delay. The suggested mechanism for this prompt thermospheric response appears to be due mainly to enhanced perpendicular electric fields. Large-scale, global changes caused by the geomagnetic storm show generally greater enhancements in the winter ( northern) hemisphere at both 0700 and 1900 local time and greater at 0700 LT than 1900 LT.