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

Abstract

Boundary dynamics are crucial for the transport of energy, mass, and momentum in geospace. The recently discovered plasmapause surface wave (PSW) plays a key role in the inner magnetosphere dynamics. However, a comprehensive investigation of spatial variations of the PSW remains absent. In this study, we elucidate the spatial characteristics of a PSW through observations from multiple spacecrafts in the magnetosphere. Following the initiation of the PSW, quasi‐periodic injections of energetic ions, rather than electrons, are suggested to serve as energy source of the PSW. Based on the distinct wave and particle signatures, we categorize the PSW into four regions: seed region, growth region, stabilization region and decay region, spanning from nightside to afternoon plasmapause. These findings advance our understanding of universal boundary dynamics and contribute to a deeper comprehension of the pivotal roles of surface waves in the energy couplings within the magnetosphere‐plasmasphere‐ionosphere system.

Special Particle Precipitation Signatures Over Giant Auroral Undulations During the 7 September 2015 Geomagnetic Storm

“…Above GUs, the ionospheric downward, forward, and nightward magnetic fields are concurrently disturbed severely, corresponding to the well-developed PSW on the plasmapause manifesting a coupled poloidal, compressional poloidal, and toroidal modes wave as indicated by Figure S2 in Supporting Information S1 and previous studies (e.g., Archer et al, 2019;He et al, 2020;Zhou et al, 2024). And the GUs have also been confirmed to be the ionospheric manifestation of the PSW, nearly sharing the same magnetic flux tubes (e.g., He et al, 2020;Zhou et al, 2022).…”

“…On one side, however, the SAPS evolves rapidly with MLT and time (e.g., He et al, 2018He et al, , 2019. On the other side, the GUs and corresponding PSW also vary with MLT and time (e.g., Lui et al, 1982;Zhou et al, 2024). Therefore, we have checked each SAPS at the equatorward of their corresponding SAs of GUs within a 30-min period herein, aiming to observe the direct evidence of GUs' scale evolving with SAPS.…”

“…Alternatively, the other theory linking the GUs to the PSW, was firstly predicted by Lui et al (1982), recently confirmed by He et al (2020), and then generalized by Zhou et al (2021Zhou et al ( , 2022 and Feng et al (2023) based on the striking similarity of location, period and relation with storm/substorm for abundant GUs and PSWs. The PSW, a kind of collective wave of poloidal, toroidal and compressional modes, can efficiently oscillate the plasmapause or the inner boundary of plasma sheet (Zhou et al, 2022(Zhou et al, , 2024, resulting in periodic modulation of electron electrostatic cyclotron harmonic (ECH) and hiss waves (Hao et al, 2023). Statistically, the anti-sunward edge of GUs is quasi-stable during their lifetime (Zhou et al, 2021), and the configuration of plasmapause boundary can control the character of ionospheric GUs (Zhou et al, 2022).…”