Correlations Between Giant Undulations and Plasmapause Configurations

• Published in: Geophysical research letters 2022-07, Vol.49 (13), p.n/a
• Main Authors: Zhou, Yi‐Jia, He, Fei, Yao, Zhong‐Hua, Wei, Yong, Zhang, Xiao‐Xin, Zhang, Yong‐Liang
• Format: Article
• Language: English
• Subjects: Amplitudes; Auroras; Configurations; Convection; Corotation; Correlation; Coupling; Defense programs; Density gradients; Diffuse aurora; DMSP satellites; Electric field; Electric fields; Energy; Energy coupling; Geomagnetic storms; giant undulations; Ion density; Ion density (concentration); Ionosphere; Magnetic storms; Magnetospheres; Magnetospheric-solar wind relationships; Meteorological satellite program; Meteorological satellites; Physics; Plasmapause; plasmapause surface waves; Plasmasphere; Satellite imagery; Satellites; Solar energy; Solar wind; Space weather; Storms; Surface waves; Thickness; Wave propagation; Wavelengths
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2022GL098627

In this letter, we report the correlations between giant undulations (GUs) and plasmapause (PP) configurations based on GUs' images and corresponding PP crossings of satellites between 2005 and 2019. Typically, GUs occur when the plasmasphere is eroded to form a thin and sharp PP during the storm main phase and early recovery phase. The thicknesses of the PP are usually comparable with the azimuthal wavelengths of the GUs and are smaller than the radial amplitudes of the GUs. The amplitudes and wavelengths are quasi‐proportional to the thicknesses of the PP and are inversely quasi‐proportional to the ion density gradients around the PP. The radial centers of GUs are typically aligned with the PP surfaces and their radial geocentric locations show positive correlations for different geomagnetic storms. These results would provide both physical insights and model constrains on the magnetosphere‐plasmasphere‐ionosphere energy coupling and the generation mechanisms of the GUs and plasmapause surface waves. Plain Language Summary The magnetosphere‐plasmasphere‐ionosphere energy coupling in geospace is one of the key focuses in the space physics and space weather researches. When the energy, mass and moment in solar wind enter into the magnetosphere, the interactions between the enhanced convection electric field and the corotation electric field will change the configurations of plasmapause (PP). A recent study found that the thin and sharper PP may be conductive to excite PP surface waves, which generate giant undulations (GUs) on the equatorward boundary of the diffuse aurora, and drive outward‐propagating ultra‐low frequency waves. However, it remains unclear how the configurations of PP exactly control the characteristics of plasmapause surface waves (PSWs) including amplitudes and wavelengths during their sunward transportation. In this letter, we report the correlations between projected GUs and the PP configurations during the propagation process of PSWs based on GUs' images and the corresponding PP crossings of Defense Meteorological Satellite Program satellites between 2005 and 2019. These results would provide both physical insights and model constrains on the magnetosphere‐plasmasphere‐ionosphere energy coupling and the generation mechanisms of GUs and PSWs. Key Points We perform the first statistical study on the correlations between giant undulations (GUs) and the plasmapause (PP) during geomagnetic storms The amplitudes and wavelengths of GUs are