Statistical Characteristics of Giant Undulations During Geomagnetic Storms

Zhou, Yi‐Jia; He, Fei; Zhang, Xiao‐Xin; Yao, Zhonghua; Wei, Yong; Zhang, Yongliang

doi:10.1029/2021gl093098

Cited by 8 publications

(35 citation statements)

References 41 publications

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“…Following the method proposed by Anderson et al (2008), the ion density dropping region with the maximum gradient near the auroral equatorial boundary was extracted to be the ionospheric footprint of the PP region (e.g., Anderson et al, 2008;Weygand et al, 2021;, as shown in Figure 1. For each GU image in the database of Zhou et al (2021), the upper and lower boundaries of the PP region (indicated by the vertical blue and red lines in the top panel of Figure 1, respectively) are identified to form the PP database in this study when there are simultaneous ion density measurements with high quality (i.e., quality flag 1 in the RPA data).…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, the SSUSI and RPA on each DMSP satellite made nearly simultaneous measurements along the trajectory. A database of GUs has been constructed in our previous work (Zhou et al., 2021). In this study, the corresponding PP parameters were extracted from the RPA measurements.…”

Section: Methodsmentioning

confidence: 99%

“…Nevertheless, further statistical investigations are still required, and it remains unclear how the configurations of the PP boundary control and modulate the PSW's characteristics. In this study, therefore, combined with the database of GUs events established by Zhou et al (2021), we compared the signatures of the projected GUs with the PP configurations, trying to answer these questions.…”

Section: Plain Language Summarymentioning

confidence: 99%

“…In this study, therefore, combined with the database of GUs events established by Zhou et al. (2021), we compared the signatures of the projected GUs with the PP configurations, trying to answer these questions.…”

Section: Introductionmentioning

confidence: 99%

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Correlations Between Giant Undulations and Plasmapause Configurations

Zhou

Yao

et al. 2022

Geophysical Research Letters

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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.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Plain Language Summarymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Correlations Between Giant Undulations and Plasmapause Configurations

Zhou

Yao

et al. 2022

Geophysical Research Letters

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“…During substorm activities, the density irregularities at nightside PBLs can be associated with fast plasma injections (Morioka & Oya, 1996; Thomas et al., 2021), which may drive inductive electric fields and cause the density irregularities subsequently (Morioka & Oya, 1996). In particular, these injections can trigger the sawtooth‐shaped giant undulations of the plasmapause surface (He et al., 2020) and may be responsible for density irregularities in PBLs at dusk and post‐dusk sectors (Zhou et al., 2021).…”

Section: Discussionmentioning

confidence: 99%

Statistical Study on Small‐Scale (≤1,000 km) Density Irregularities in the Inner Magnetosphere

Liu

Xia

et al. 2022

JGR Space Physics

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In the Earth's inner magnetosphere, which generally lies within L-shell = 7, the cold plasma population (∼1 eV) is divided into three spatial regions: the plasmasphere, the plasma trough, and the plasmasphere boundary layer (PBL). The plasmasphere is a torus-like, high-density (≥50 cc) region around the Earth, while the surrounding plasma trough is tenuous (∼ 1 cc). Between the two regions is the PBL (or the plasmapause), with large density gradients and often accompanied by significant density structures (Carpenter & Lemaire, 2004). The location of PBL, which is controlled by global convection (Chappell, 1972;Nishida, 1966), is highly dynamic in response to geomagnetic activities: it varies from L = 2-3 due to erosion during active conditions (Carpenter & Anderson, 1992;Moldwin et al., 2002) to L ∼ 7 due to refilling during prolonged quiet conditions (Kwon et al., 2015). One large-scale (∼1 R E ) structure near the PBL is the plasmaspheric plume, which is peeled away from the plasmasphere by enhanced convection fields (Chen & Wolf, 1972;Goldstein et al., 2004). Other medium-density to large-density structures (>0.1 R E ) include the notches, channels, shoulders, fingers, and crenulations observed in EUV (extreme ultraviolet) images (Darrouzet et al., 2009;Spasojević et al., 2003).Small-scale density irregularities have cross-field scales ranging from ∼10 m to ∼1,000 km and occur in all parts of the inner magnetosphere (Sonwalkar, 2006). They have been extensively observed in the PBL (Décréau et al., 2005) and plume regions (Borovsky & Denton, 2008;Goldstein et al., 2004). Small-scale density irregularities are generally thought to be field-aligned structures and thus are referred to as field-aligned irregularities

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Statistical Properties of Long‐Period Plasmapause Surface Waves From Van Allen Probes Observations

et al. 2023

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Recent work revealed the existence of plasmapause surface waves (PSWs) with Van Allen Probes observations, which are characterized by the periodic modulations of both magnetic/electric fields and plasma densities, and suggested to be the driver of giant undulations (GUs). In this study, six years data from Van Allen Probes were used to investigate the spatial distributions and occurrence conditions of PSWs in the period of 5–30 min. PSWs are found to be mainly distributed at L = 3.5–7 and their occurrence rate is increasing with larger L shells. In the azimuth direction, the spatial distribution of PSWs exhibits an obvious dawn‐dusk asymmetry with highest occurrence rates at MLT = 15–21, which is consistent with the spatial distribution of GUs revealed in the previous study. This further demonstrates that PSWs and GUs are connected, and indicates that PSWs differ from Ps6 waves which have a similar wave period and irregular waveform but mainly concentrate in the dawnside and connect with Ω bands. PSWs preferentially occur under the condition of high solar wind velocities (VSW > 500 km/s) and high dynamic pressures (Pdyn > 5 nPa), and their occurrence rate has a negative correlation with IMF Bz, SYMH and AL. Statistical results also reveal that PSWs preferentially occur around the peak of both magnetic storms and substorms. These findings may shed new lights on the further understanding of PSWs' generation and propagation.

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Statistical Characteristics of Giant Undulations During Geomagnetic Storms

Cited by 8 publications

References 41 publications

Correlations Between Giant Undulations and Plasmapause Configurations

Correlations Between Giant Undulations and Plasmapause Configurations

Statistical Study on Small‐Scale (≤1,000 km) Density Irregularities in the Inner Magnetosphere

Statistical Properties of Long‐Period Plasmapause Surface Waves From Van Allen Probes Observations

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