Intense Equatorial Electrojet and Counter Electrojet caused by the 15 January 2022 Tonga Volcanic Eruption: Space and Ground-based Observations

Equatorial plasma bubbles (EPBs) are the irregularities in the post-sunset equatorial/low-latitude ionosphere, manifesting as spread-F in ionograms (Bekner & Wells, 1934), scintillations in radio signals (Whitney & Malik, 1968), bite-outs in ion-density measurements (Hanson & Sanatani, 1973), plume structures in radar maps (Woodman & La Hoz, 1976), and intensity depletions in airglow images (Weber et al., 1978). EPBs are initiated by Rayleigh-Taylor instability (Dungey, 1956) operating in the post-sunset bottom-side F-region where vertical plasma density gradient is anti-parallel to gravity, under favorable conditions of seed perturbations, sharper plasma density gradients, smaller ion-neutral collisions, and stronger vertical plasma drifts (Sultan, 1996). Several review articles discuss the history and progress in the theoretical and technical evolution of EPB monitoring (

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Pronounced Suppression and X‐Pattern Merging of Equatorial Ionization Anomalies After the 2022 Tonga Volcano Eruption

Zhang

Wang

et al. 2022

JGR Space Physics

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Following the 2022 Tonga Volcano eruption, dramatic suppression and deformation of the equatorial ionization anomaly (EIA) crests occurred in the American sector ∼14,000 km away from the epicenter. The EIA crests variations and associated ionosphere‐thermosphere disturbances were investigated using Global Navigation Satellite System total electron content data, Global‐scale Observations of the Limb and Disk ultraviolet images, Ionospheric Connection Explorer wind data, and ionosonde observations. The main results are as follows: (a) Following the eastward passage of expected eruption‐induced atmospheric disturbances, daytime EIA crests, especially the southern one, showed severe suppression of more than 10 TEC Unit and collapsed equatorward over 10° latitudes, forming a single band of enhanced density near the geomagnetic equator around 14–17 UT, (b) Evening EIA crests experienced a drastic deformation around 22 UT, forming a unique X‐pattern in a limited longitudinal area between 20 and 40°W. (c) Thermospheric horizontal winds, especially the zonal winds, showed long‐lasting quasi‐periodic fluctuations between ±200 m/s for 7–8 hr after the passage of volcano‐induced Lamb waves. The EIA suppression and X‐pattern merging was consistent with a westward equatorial zonal dynamo electric field induced by the strong zonal wind oscillation with a westward reversal.

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Intense Equatorial Electrojet and Counter Electrojet caused by the 15 January 2022 Tonga Volcanic Eruption: Space and Ground-based Observations

Abstract: This a preprint and has not been peer reviewed. Data may be preliminary.

Cited by 4 publications

References 32 publications

Extreme poleward expanding super plasma bubbles triggered by Tonga volcano eruption during the recovery phase of geomagnetic storm

Extreme poleward expanding super plasma bubbles triggered by Tonga volcano eruption during the recovery phase of geomagnetic storm

Extreme Poleward Expanding Super Plasma Bubbles Over Asia‐Pacific Region Triggered by Tonga Volcano Eruption During the Recovery‐Phase of Geomagnetic Storm

Pronounced Suppression and X‐Pattern Merging of Equatorial Ionization Anomalies After the 2022 Tonga Volcano Eruption

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