Abstract

We present a case study of ionospheric and magnetospheric response to a prolonged interval of strongly northward IMF along with enhanced solar wind dynamic pressure on November 9, 2004. Comprehensive space and ground based observations are examined to investigate global electrodynamic properties ... Show moreWe present a case study of ionospheric and magnetospheric response to a prolonged interval of strongly northward IMF along with enhanced solar wind dynamic pressure on November 9, 2004. Comprehensive space and ground based observations are examined to investigate global electrodynamic properties of the ionosphere and magnetosphere under northward IMF conditions, including the Cluster satellites located near the high-altitude southern cusp region, the low-altitude DMSP and Fast spacecraft, and ground radar network and magnetometer chains. Global patterns of high-latitude ionospheric convection obtained from the assimilative mapping of ionospheric electrodynamics (AMIE) procedure based on various ground and low-altitude spacecraft measurements show the formation of reserved ionospheric convection in both northern and southern hemispheres simultaneously for nearly 2 hours. Global MHD simulations are also carried out to investigate the physical processes involved in the solar wind-magnetosphere-ionosphere interaction, particularly, the reconnection configuration near the magnetopause, the transport of mass and energy, and the coupling between the magnetosphere and the ionosphere during northward IMF. Cluster observations indicate that multiple magnetopause crossings had been encountered by the spacecraft due to variations in the solar wind dynamic pressure, and the plasma characteristics are consistent with magnetic reconnection taking place tailward of the spacecraft location. Show less