Affiliation:
1. Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China
2. College of Earth and Planetary Sciences University of Chinese Academy of Sciences Beijing China
3. Heilongjiang Mohe National Observatory of Geophysics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China
4. Beijing National Observatory of Space Environment Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China
Abstract
AbstractThis paper conducts a multi‐instrument analysis of a latitudinal plasma density peak at the middle latitudes during the early recovery phase of the April 2023 geomagnetic storm. The total electron content (TEC), peak density of the F layer, and the in situ plasma density from Swarm and Defense Meteorological Satellite Program (DMSP) satellites all capture this peak feature. This narrow latitudinal peak structure appeared around 50°N and extended from 40°E to 150°E in longitude with a prolonged duration of about 8 hr from sunset to midnight. This mid‐latitude peak reveals a noticeable equatorward motion and a slight westward shift. According to the plasma composition observations from DMSP satellites, this peak structure shows an O+ ions dominance, which means that this peak is more likely to be formed by an internal rather than an external source from the plasmasphere. Meanwhile, the middle latitude Fabry–Perot interferometer (FPI) observed strong equatorward thermospheric winds, and the peak height of the F layer presented a visible elevation, which suggests that the equatorward wind lifting caused the plasma density enhancement. Besides, the O/N2 ratio significantly decreased at lower and middle latitudes, and ion drift observations showed a distinct subauroral westward channel. Based on these simultaneous measurements, this structure's sharp equatorward and poleward boundaries might be related to the O/N2 ratio change and the subauroral polarization stream (SAPS) flow separately.
Funder
National Natural Science Foundation of China
National Key Research and Development Program of China
Publisher
American Geophysical Union (AGU)