Correlations Between Giant Undulations and Plasmapause Configurations

Abstract

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.

A Radial Standing Pc5‐6 Wave and Its Energy Coupling With Field Line Resonance Within the Dusk‐Sector Magnetosphere

“…The similar intensified geomagnetic disturbance and enhanced ionospheric aurora were not observed near the conjugated region of RA/E1 (near BJN station), corresponding well with no evidence of strong FLR/toroidal fluctuations during the RA1 and RE1 intervals from Figures 3 and 4. Interestingly, the evident giant undulations (GUs; e.g., Forsyth et al, 2020;Lui et al, 1982;Zhou et al, 2021Zhou et al, , 2022 appear on the equator edge of diffuse aurora in Figures 5a and 5b, which are excited by the ∼1.3 mHz plasmapause surface wave on the dusk-sector plasmapause, as first evidenced by He et al (2020) in the same GUs event. Their potential relationship deserves a further investigation, based on the large GUs database established by Zhou et al (2021Zhou et al ( , 2022.…”

“…Interestingly, the evident giant undulations (GUs; e.g., Forsyth et al, 2020;Lui et al, 1982;Zhou et al, 2021Zhou et al, , 2022 appear on the equator edge of diffuse aurora in Figures 5a and 5b, which are excited by the ∼1.3 mHz plasmapause surface wave on the dusk-sector plasmapause, as first evidenced by He et al (2020) in the same GUs event. Their potential relationship deserves a further investigation, based on the large GUs database established by Zhou et al (2021Zhou et al ( , 2022.…”

“…Their potential relationship deserves a further investigation, based on the large GUs database established by Zhou et al. (2021, 2022).…”

Spatial Evolution Characteristics of Plasmapause Surface Wave During a Geomagnetic Storm on 16 July 2017

“…It responds well to geomagnetic activity (e.g., Goldstein, Spasojevic, et al, 2003;He et al, 2017), correlates with auroral signatures (X. X. Zhang, He, Chen, et al, 2017;Zhou et al, 2022), and affects energetic particle precipitation in the ring current and radiation belts through wave-particle interactions (e.g., Ganguli et al, 2000;Kotova, 2007;Liemohn, 2006;Pierrard et al, 2009;Whittaker et al, 2014).…”

“…However, short-timescale impulsive drivers result in complicated superpositions of ultralow frequency (ULF) wave modes (e.g., James et al, 2013;Miyashita et al, 2021;Villante et al, 2016), hindering subsequent progress. Only in recent years have direct, conclusive observational evidence of magnetopause surface eigenmodes (MSE; Archer et al, 2019Archer et al, , 2021 and plasmapause surface waves (PSW; Hao et al, 2023;He et al, 2020;Zhou et al, 2021Zhou et al, , 2022 been captured through combined space-borne and ground-based instruments. MSE is mostly excited by impulsive dynamic pressure variations on the dayside magnetopause (e.g., Archer et al, 2013Archer et al, , 2019Hartinger et al, 2015), while PSW may be excited by the substorm-associated pressure impinging on the nightside plasmapause (Hao et al, 2023;He et al, 2020).…”