Numerical modeling of solar wind influences on the dynamics of the high-latitude upper atmosphere

[摘要] Neutral thermospheric wind patterns at high latitudes obtainedfrom cross-track acceleration measurements of the CHAMP satelliteabove both polar regions are used to deduce statistical neutralwind vorticity distributions and were analyzed in their dependence onthe Interplanetary Magnetic Field (IMF).The average pattern confirms the large duskside anticyclonic vortex seenin the average wind pattern and reveals a positive (cyclonic) vorticity on thedawnside, which is almost equal in magnitude to the duskside negative one.The IMF dependence of the vorticity pattern resembles the characteristicfield-aligned current (FAC) and ionospheric plasma drift pattern knownfrom various statistical studies obtained under the same sorting conditionsas, e.g., the EDI Cluster statistical drift pattern.There is evidence for hemispheric differences in the average magnitudesof the statistical patterns both for plasma drift and even more for theneutral wind vorticity.The paper aims at a better understanding of the globally interconnected complexplasma physical and electrodynamic processes of Earth's upper atmosphere by meansof first-principle numerical modeling using the Upper Atmosphere Model (UAM).The simulations of, e.g., thermospheric neutral wind and mass density at highlatitudes are compared with CHAMP observations for varying IMF conditions.They show an immediate response of the upper atmosphere and its highsensitivity to IMF changes in strength and orientation.

[学科分类] 电子、光学、磁材料