On the Generation of Pre‐Sunrise Equatorial Plasma Bubbles in Southeast Asia During the Geomagnetic Storm of May 2024

Information from the abstract

Abstract A set of fresh Equatorial Plasma Bubbles (EPBs) formed during pre‐sunrise hours in the Southeast Asian sector amid the recovery phase of May 2024 geomagnetic storm. They offered new insights into their formation mechanism. This study used Total Electron Content (TEC) and Rate of TEC Index maps over Indonesia, along with ionosondes in Thailand and Vietnam, magnetometers in South American sectors, and prompt penetration electric field (PPEF) modeling, to reveal these insights. The first insight from our observations was that the pre‐sunrise EPBs were initiated by the eastward overshielding PPEF linked to the northward turn of the Interplanetary Magnetic Field Bz. Then, the disturbance dynamo electric field, expected to operate during the storm's recovery phase, might maintain the survival of the EPBs. The second, and more intriguing, insight is that these pre‐sunrise EPBs formed at specific longitudes, where TEC values had already decreased since the post‐sunset hours. Further investigation showed that these lower TEC regions consist of large plasma density gradients, serving as favorable conditions necessary for EPB formation near sunrise. Finally, this study implied that, even during a strong eastward electric field in an intense storm, preconditioning or favorable conditions, such as larger plasma density gradients, are required for pre‐sunrise EPB generation. The storm‐driven electric field then causes the pre‐sunrise EPBs to develop at distinctive longitudes where these favorable conditions are located.

Why this record is monitored

This record has an Impact Signal of 70/100 based on recency, source, collaboration, and bibliographic signals. It prioritizes monitoring and is not a judgment of research quality.

Related topics: Ionosphere and magnetosphere dynamics · Lightning and Electromagnetic Phenomena · Solar and Space Plasma Dynamics