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Intense Equatorial Electrojet and Counter Electrojet caused by the 15 January 2022 Tonga Volcanic Eruption: Space and Ground-based Observations
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  • Guan Le,
  • Guiping Liu,
  • Endawoke Yizengaw,
  • Christoph R Englert
Guan Le
NASA Goddard Space Flight Center, NASA Goddard Space Flight Center

Corresponding Author:guan.le@nasa.gov

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Guiping Liu
University of California, Berkeley, University of California, Berkeley
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Endawoke Yizengaw
The Aerospace Corporation, The Aerospace Corporation
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Christoph R Englert
Naval Research Laboratory, Naval Research Laboratory
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We present space and ground-based multi-instrument observations demonstrating the impact of the 2022 Tonga volcanic eruption on dayside equatorial electrodynamics. A strong counter electrojet (CEJ) was observed by Swarm and ground-based magnetometers on 15 January after the Tonga eruption and during the recovery phase of a moderate geomagnetic storm. Swarm also observed an enhanced equatorial electrojet (EEJ) preceding the CEJ in the previous orbit. The observed EEJ and CEJ exhibited complex spatiotemporal variations. We combine them with the Ionospheric Connection Explorer (ICON) neutral wind measurements to disentangle the potential mechanisms. Our analysis indicates that the geomagnetic storm had minimal impact; instead, a large-scale atmospheric disturbance propagating eastward from the Tonga eruption site was the most likely driver for the observed intensification and directional reversal of the equatorial electrojet. The CEJ was associated with strong eastward zonal winds in the E-region ionosphere, as a direct response to the lower atmosphere forcing.