Identification of Penetration and Disturbance Dynamo Electric Fields and Their Effects on the Generation of Equatorial Plasma Bubbles

• Published in: Journal of geophysical research. Space physics 2023-11, Vol.128 (11), p.n/a
• Main Author: Huang, Chao‐Song
• Format: Article
• Language: English
• Subjects: Bubbles; Disturbance; disturbance dynamo electric field; Electric fields; Empirical analysis; geomagnetic storm; Geomagnetic storms; Interplanetary magnetic field; Magnetic fields; Magnetic storms; Navigation systems; penetration electric field; Plasma bubbles; Plasma drift; Recovery; Storms; Vertical drift
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2023JA031766

A very challenging task in ionospheric studies is to determine the separate contributions of penetration and disturbance dynamo processes in the generation of equatorial plasma drift during magnetic storms. In this study, we analyze the ion drift measured by the Communications/Navigation Outage Forecasting System satellite during the magnetic storm on 15–16 July 2012. A unique feature of this storm is the exceptionally long period of continuous southward interplanetary magnetic field (IMF) for 32 hr. The storm‐induced net change of the meridional/vertical ion drift, the difference drift between the storm time and the quiet time, is derived during the storm main phase and the first 20 hr of the recovery phase with southward IMF. The difference drift during the recovery phase cannot be explained by the disturbance dynamo effect alone. A new method is used to separate the drifts caused by the penetration and disturbance dynamo processes. The penetration drift is represented by an empirical pattern of penetration electric field and depends on the IMF magnitude, and the disturbance dynamo drift is obtained by subtracting the penetration drift from the measured difference drift. The derived disturbance dynamo drift is in good agreement with previous statistical pattern. This is the first effort to identify the separate contributions of the penetration and disturbance dynamo processes to the total drift from observed data. The results have important implications in identifying storm‐time penetration and disturbance dynamo electric fields and their effects on the generation and evolution of plasma bubbles. Key Points A new method is proposed to separate the storm‐time penetration and disturbance dynamo electric fields from ion drift measurements The derived disturbance dynamo drifts in this storm are in reasonable agreement with previous statistical pattern The combined penetration and dynamo effects provide a good explanation of post‐midnight plasma bubbles during the storm recovery phase