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Conjugate ionospheric perturbation during the 2017 solar eclipse
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  • Shun-Rong Zhang,
  • Philip J Erickson,
  • Juha Vierinen,
  • Ercha Aa,
  • William Rideout,
  • Anthea J. Coster,
  • Larisa P. Goncharenko
Shun-Rong Zhang
MIT Haystack Observatory

Corresponding Author:[email protected]

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Philip J Erickson
Massachusetts Institute of Technology
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Juha Vierinen
University of Tromso
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Ercha Aa
National Space Science Center, Chinese Academy of Sciences
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William Rideout
Massachusetts Institute of Technology
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Anthea J. Coster
Haystack Observatory Mass. Inst.Technology
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Larisa P. Goncharenko
Massachusetts Institute of Technology, Haystack Observatory
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We report new findings of total electron content (TEC) perturbations in the southern hemisphere at conjugate locations to the northern eclipse on 21 August 2017. We identified a persistent conjugate TEC depletion by 10-15\% during eclipse time, elongating along magnetic latitudes with $\sim$5$^\circ$ latitudinal width, moving equatorward, and becoming most pronounced at lower magnetic latitudes ($<$20$^\circ$S) when the ionosphere in the northern low latitudes were masked. This depletion was coincident with a weakening of the southern crest of the equatorial ionization anomaly (EIA), while the northern EIA crest stayed almost undisturbed or was slightly enhanced. We suggest these conjugate perturbations were associated with dramatic eclipse initiated plasma pressure reductions in the flux tubes, with a large portion of shorter tubes located at low latitudes underneath the Moon’s shadow. These small L-shell tubes transversed the F region ionosphere at low and equatorial latitudes. The plasma pressure gradient was markedly skewed northward in the flux tubes at low and equatorial latitudes, as was the neutral pressure. These effects caused a general northward motion tendency for plasma within the flux tubes, and inhibited normal southward diffusion of equatorial fountain plasma into the southern EIA region.
Feb 2021Published in Journal of Geophysical Research: Space Physics volume 126 issue 2. 10.1029/2020JA028531