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Abstract:
This study examines the responses of polar electrojets (PEJs) and thermospheric zonal winds to enhancements in solar wind dynamic pressure (Pd), based on 10 years of CHAMP satellite observations. The results reveal that solar wind Pd jumps lead to a global intensification and equatorward shift of both PEJs and zonal winds, with pronounced asymmetries in local time and seasonal behavior. While zonal wind responses generally follow the expected direction from ion drag, they are notably modulated by the interplay with the Coriolis and pressure gradient forces—particularly in the dawn sector. Wind enhancements are strongest where these forces act synergistically, especially in the dusk and noon sectors dominated by eastward PEJs. Following solar wind Pd jumps, the peak latitudes of PEJs shift equatorward; however, this shift lags behind the increase in current intensity, suggesting a delayed magnetospheric reconfiguration. Zonal wind peaks tend to align with the peak latitude of the eastward PEJ and the midnight westward PEJ but are displaced by approximately 2° poleward at noon and 2° equatorward at dawn relative to the westward PEJ. Solar wind Pd‐induced current enhancements exhibit seasonal variations different from those of the background currents, while summer–winter differences in zonal winds are most pronounced at noon and dawn.
