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Impacts of the January 2022 Tonga volcanic eruption on the ionospheric dynamo: ICON-MIGHTI and Swarm observations of extreme neutral winds and currents
  • +6
  • Brian J Harding,
  • Yen-Jung Joanne Wu,
  • Patrick Alken,
  • Yosuke Yamazaki,
  • Colin Triplett,
  • Thomas J. Immel,
  • L. Claire Gasque,
  • Stephen B Mende,
  • Chao Xiong
Brian J Harding
University of California, Berkeley, University of California, Berkeley, University of California, Berkeley

Corresponding Author:[email protected]

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Yen-Jung Joanne Wu
University of California, Berkeley, University of California, Berkeley, University of California, Berkeley
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Patrick Alken
University of Colorado Boulder, University of Colorado Boulder, University of Colorado Boulder
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Yosuke Yamazaki
GFZ German Research Centre for Geosciences, GFZ German Research Centre for Geosciences, GFZ German Research Centre for Geosciences
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Colin Triplett
University of California, Berkeley, University of California, Berkeley, University of California, Berkeley
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Thomas J. Immel
University of California, Berkeley, University of California, Berkeley, University of California, Berkeley
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L. Claire Gasque
University of California, Berkeley, University of California, Berkeley, University of California, Berkeley
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Stephen B Mende
University of California, Berkeley, University of California, Berkeley, University of California, Berkeley
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Chao Xiong
Wuhan University, Wuhan University, Wuhan University
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Abstract

The eruption of the Hunga Tonga-Hunga Ha’apai volcano on 15 January 2022 triggered atmospheric waves at all altitudes. The NASA Ionospheric Connection Explorer (ICON) and ESA Swarm satellites were well placed to observe its impact on the ionospheric wind dynamo. After the Lamb wave entered the dayside, Swarm A observed an eastward and then westward equatorial electrojet (EEJ) on two consecutive orbits, each with magnitudes exceeding the 99.9th percentile of typically observed values. ICON simultaneously observed the neutral wind (90-300 km altitude) at approximately the same distance from Tonga. The observed neutral winds were also extreme (>99.9th percentile at some altitudes). The covariation of EEJ and winds is consistent with recent theoretical and observational results, indicating that the westward electrojet is driven by strong westward winds in the Pedersen region (~120-150 km). These observations imply that the dynamo is a key mechanism in the ionospheric response to the Tonga disturbance.