Journal Article

Midlatitude Plasma Blob‐like Structures Along With Super Equatorial Plasma Bubbles During the May 2024 Great Geomagnetic Storm

Li, Yu, Shinbori, Atsuki, Li, Yi, Nishioka, Michi, Li, Guozhu, Zhang, Shun‐Rong, Xie, Haiyong, Ning, Baiqi, Hu, Lianhuan, Zhao, Xiukuan, Dai, Guofeng, Perwitasari, Septi, Sun, Wenjie, Otsuka, Yuichi, Liu, Libo, Liu, Jianfei, Zhao, Biqiang

2024

Overview

Plasma blob is generally a low‐latitude phenomenon occurring at the poleward edge of equatorial plasma bubble (EPB) during post‐sunset periods. Here we report a case of midlatitude ionospheric plasma blob‐like structures occurring along with super EPBs over East Asia around sunrise during the May 2024 great geomagnetic storm. Interestingly, the blob‐like structures appeared at both the poleward and westward edges of EPBs, reached up to 40°N magnetic latitudes, and migrated westward several thousand kilometers together with the bubble. The total electron content (TEC) inside the blob‐like structures was enhanced by ∼50 TEC units relative to the ambient ionosphere. The blob‐like structure at the EPB poleward edge could be partly linked with field‐aligned plasma accumulation due to poleward development of bubble. For the blob‐like structure at the EPB west side, one possible mechanism is that it was formed and enhanced accompanying the bubble evolution and westward drift. Plain Language Summary Accompanying the generation of equatorial plasma bubble (EPB), an extra structure with plasma density enhancement may occur. The density‐enhanced structure is known as plasma blob. Generally, plasma blobs mainly appear at the poleward edge of EPB, being low‐latitude phenomena occurring at 10–20° magnetic latitudes. Whereas previous simulations showed that plasma blobs could appear at the east/west side of EPBs, there were few observational evidences and the driving mechanism is unclear. In this study, midlatitude plasma blob‐like structures occurring up to 40°N magnetic latitude was observed along with super EPBs during magnetic storm. Different from most blobs appearing at the EPB poleward edge, the blob‐like structures in the present study appeared at both the EPB poleward and westward edges. By using ground‐based observations from GNSS receiver networks and in‐situ measurements onboard spacecraft, the morphology and evolution of the super plasma blob‐like structures are visualized. Potential mechanisms responsible for their generation are investigated. The results highlight the coexistence of large‐scale plasma depletion and blob structures and their complex evolution with longitude and latitude, and have implications for better understanding the sudden changes of plasma density in time and altitude observed by radar. Key Points Super plasma blob‐like structures occurred up to 40°N MLat along with equatorial plasma bubbles near sunrise during storm time The blob‐like structures mainly occurred at the bubble poleward and westward edges and migrated westward along with the bubble The poleward development and evolution of the bubble could contribute to the formation of super blob‐like structures

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Bubbles / Case reports / Coexistence / Evolution / Geomagnetic storms / Geomagnetism / Ionosphere / Ionospheric plasma / Latitude / magnetic storm / Magnetic storms / Plasma / plasma blob / plasma bubble / Plasma bubbles / Plasma density / Radar / Satellite observation / Spacecraft / Storms / Structures / TEC enhancement / Total Electron Content