Prompt thermospheric response to the 6 November 2001 magnetic storm

摘要

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.