IMF B_z周期震荡期间日间热层扰动风的经度差异分析

By using the coupled magnetosphere-thermosphere-ionosphere model, we explore the longitudinal dependences of the dayside neutral wind in response to the 60 min periodic oscillation of the interplanetary magnetic field (IMF) B_z. The southward propagation of the traveling atmospheric disturbances (TADs) in meridional wind stands at about 20° MLat, which is related to the geomagnetic field configuration, neutral temperature, and electron density changes. The meridional wind travels continuously from high to low latitude in the western southern hemisphere, with several sudden changes in the wave phase along the propagation direction. The sudden changes in the wave phase that is induced by the interaction between TADs and simultaneous responses of the meridional winds driven by oscillating solar wind conditions is induced by the stronger roles of the ion drag than the pressure gradient, with the magnitudes of acceleration in meridional winds due to ion drag and pressure gradient are -4 and 3 cm•s^-2, respectively. Note here that the mean circulation is the background meridional winds in the base case with the IMF B_z setting to zero in the CMIT model. The ion drag shows obvious longitudinal differences associated with the penetration of the ionospheric electric field during the oscillation of IMF B_z.