Abstract
This study reports the rare ultralow-frequency(ULF)wave activity associated with the solar wind dynamic pressure en-hancement that was successively observed by the GOES-17(Geostationary Operational Environmental Satellite)in the mag-netosphere,the CSES(China Seismo-Electromagnetic Satellite)in the ionosphere,and the THEMIS ground-based observatories(GBO)GAKO and EAGL in the Earth's polar region during the main phase of an intense storm on 4 November 2021.Along with the enhanced-pressure solar wind moving tailward,the geomagnetic field structure experienced a large-scale change.From dawn/dusk sides to midnight,the GAKO,EAGL,and GOES-17 sequentially observed the ULF waves in a frequency range of 0.04-0.36 Hz at L shells of～5.07,6.29,and 5.67,respectively.CSES also observed the ULF wave event with the same frequency ranges at wide L-shells of 2.52-6.22 in the nightside ionosphere.The analysis results show that the ULF waves at ionospheric altitude were mixed toroidal-poloidal mode waves.Comparing the ULF waves observed in different regions,we infer that the nightside ULF waves were directly or indirectly excited by the solar wind dynamic pressure increase:in the area of L-shells～2.52-6.29,the magnetic field line resonances(FLRs)driven by the solar wind dynamic pressure increase is an essential excitation source;on the other hand,around L～3.29,the ULF waves can also be excited by the outward expansion of the plasmapause owing to the decrease of the magnetospheric convection,and in the region of L-shells～5.19-6.29,the ULF waves are also likely excited by the ion cyclotron instabilities driven by the solar wind dynamic pressure increase.
基金项目
National Key Research and Development Program of China(2023YFE0117300)
National Natural Science Foundation of China(4187417)
APSCO Earthquake Research Project Phase Ⅱ()
Dragon 5 Cooperation 2020-2024(59236)
维普
万方数据