Significant Ionospheric Hole and Equatorial Plasma Bubbles After the 2022 Tonga Volcano Eruption. Issue 7 (11th July 2022)

• Record Type: Journal Article
• Authors: Aa, Ercha; Zhang, Shun‐Rong; Erickson, Philip J.; Vierinen, Juha; Coster, Anthea J.; Goncharenko, Larisa P.; Spicher, Andres; Rideout, William
• Is Part Of: Space weather. Volume 20:Issue 7(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-11
• Subjects: Tonga volcano eruption -- equatorial plasma bubbles -- traveling ionospheric disturbances -- ionospheric hole -- lamb waves -- Beidou GEO TEC; Space environment -- Periodicals; 551.509992
• DOI: 10.1029/2022SW003101
• Languages: English
• ISSNs: 1542-7390

Abstract

Abstract: This paper investigates the local and global ionospheric responses to the 2022 Tonga volcano eruption, using ground‐based Global Navigation Satellite System total electron content (TEC), Swarm in situ plasma density measurements, the Ionospheric Connection Explorer (ICON) Ion Velocity Meter (IVM) data, and ionosonde measurements. The main results are as follows: (a) A significant local ionospheric hole of more than 10 TECU depletion was observed near the epicenter ∼45 min after the eruption, comprising of several cascading TEC decreases and quasi‐periodic oscillations. Such a deep local plasma hole was also observed by space‐borne in situ measurements, with an estimated horizontal radius of 10–15° and persisted for more than 10 hr in ICON‐IVM ion density profiles until local sunrise. (b) Pronounced post‐volcanic evening equatorial plasma bubbles (EPBs) were continuously observed across the wide Asia‐Oceania area after the arrival of volcano‐induced waves; these caused a N e decrease of 2–3 orders of magnitude at Swarm/ICON altitude between 450 and 575 km, covered wide longitudinal ranges of more than 140°, and lasted around 12 hr. (c) Various acoustic‐gravity wave modes due to volcano eruption were observed by accurate Beidou geostationary orbit (GEO) TEC, and the huge ionospheric hole was mainly caused by intense shock‐acoustic impulses. TEC rate of change index revealed globally propagating ionospheric disturbances at a prevailing Lamb‐wave mode of ∼315 m/s; the large‐scale EPBs could be seeded by acoustic‐gravity resonance and coupling to less‐damped Lamb waves, under a favorable condition of volcano‐induced enhancement of dusktime plasma upward E×B drift and postsunset rise of the equatorial ionospheric F‐layer. Plain Language Summary: The catastrophic 2022 Tonga volcano eruption triggered giant atmospheric waves that propagated into and strongly impacted Earth's ionosphere. Using ground‐based multi‐Global Navigation Satellite System total electron content (TEC) and ionosonde measurements as well as space‐borne Swarm and Ionospheric Connection Explorer satellites observations, we found large‐scale, intense ionospheric disturbances. The eruption created a large ionospheric hole near the epicenter embedded with cascading TEC drops and periodic oscillations, resulting from various shock‐acoustic wave impulses. Atmospheric Lamb waves propagated globally at a velocity of ∼315 m/s, coupled to ionosphere heights possibly via acoustic‐gravity resonance, and caused global‐scale ionospheric disturbances. We report for the first time that strong nighttime equatorial plasma bubbles were continuously observed over the vast Asia‐Oceania area of more than 140° longitudinal range, lasting around 12 hr following the consecutive arrival of volcano‐induced waves and the dusk terminator. These results demonstrate far‐reaching and long‐lasting atmosphere‐ionosphere impacts from a devastating natural disaster, and highlight new ways in which surface conditions can impact the upper atmosphere. Key Points: Shock‐acoustic impulses created a significant ionospheric hole of 10+ TECU depletion near the epicenter, with an estimated radius of 10–15° Pronounced post‐volcanic equatorial plasma bubbles were continuously developed across the Asia‐Oceania area covering ∼140° longitudes Strong plasma bubbles were likely triggered by gravity wave resonance with Lamb waves and volcano‐increased PRE/PSSR of equatorial F‐layer