Abstract

In this presentation, we investigate the response of the ring current pressure (pressure gradient) and field-aligned current (FAC) patterns in the high-latitude ionosphere to the May 2005 geomagnetic storm using a Coupled Magnetosphere Ionosphere Thermosphere (CMIT) 2.0 model simulation and Energ... Show moreIn this presentation, we investigate the response of the ring current pressure (pressure gradient) and field-aligned current (FAC) patterns in the high-latitude ionosphere to the May 2005 geomagnetic storm using a Coupled Magnetosphere Ionosphere Thermosphere (CMIT) 2.0 model simulation and Energetic Neutral Atom (ENA) image observations obtained by IMAGE/HENA. The CMIT model driven by upstream solar wind can provide the global structure of plasma and field of the coupled magnetosphere-ionosphere system, requiring the conservation of currents in this system. Based on the assumption of quasi-steady state MHD force balance that pressure gradients in equatorial ring current drive field-aligned currents for large spatial and slow temporal scale changes of magnetic field, the FAC in the high-latitude ionosphere can be calculated from the inverted pressure distributions from ENA images and empirical geomagnetic field. The temporal and spatial ring current pressure distributions and the FAC distributions in the high-latitude ionosphere from the CMIT model are used to morphologically compare with that deduced from ENA images. It is found that the simulated pressure patterns are basically in agreement with the deduced pressure patterns from ENA images, whereas the simulated FAC distributions are different from the calculated FAC patterns due to different geomagnetic fields. In order to better understand the dynamics of the relationship between the ring current plasma pressure/pressure gradients and field-aligned currents in the high-latitude ionosphere, the preliminary results will be addressed in this presentation. Show less