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Significant ionospheric hole and equatorial plasma bubbles after the 2022 Tonga volcano eruption
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  • Ercha Aa,
  • Shun-Rong Zhang,
  • Philip J Erickson,
  • Juha Vierinen,
  • Anthea J. Coster,
  • Larisa P. Goncharenko,
  • Andres Spicher,
  • William Rideout
Ercha Aa
MIT Haystack Observatory, MIT Haystack Observatory

Corresponding Author:[email protected]

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Shun-Rong Zhang
MIT Haystack Observatory, MIT Haystack Observatory
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Philip J Erickson
MIT Haystack Observatory, MIT Haystack Observatory
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Juha Vierinen
The Arctic University of Norway, The Arctic University of Norway
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Anthea J. Coster
MIT Haystack Observatory, MIT Haystack Observatory
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Larisa P. Goncharenko
MIT Haystack Observatory, MIT Haystack Observatory
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Andres Spicher
UiT The Arctic University of Norway, UiT The Arctic University of Norway
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William Rideout
MIT Haystack Observatory, MIT Haystack Observatory
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Abstract

This paper investigates the local and global ionospheric responses to the 2022 Tonga volcano eruption, using ground-based Global Navigation Satellite System (GNSS) 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: (1) 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 deg and persisted for more than 10 hours in ICON-IVM ion density profiles until local sunrise. (2) 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 Ne decrease of 2-3 orders of magnitude at Swarm/ICON altitude between 450-575~km, covered wide longitudinal ranges of more than 140 deg and lasted around 12 hours. (3) 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 ExB drift and postsunset rise of the equatorial ionospheric F-layer.