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The effect of midnight temperature maximum winds on post-midnight equatorial spread F
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  • Jonathan Krall,
  • Dustin A Hickey,
  • J.D. Huba,
  • PATRICK B DANDENAULT
Jonathan Krall
Naval Research Laboratory

Corresponding Author:[email protected]

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Dustin A Hickey
United States Naval Research Laboratory
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J.D. Huba
Syntek Technologies
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PATRICK B DANDENAULT
Johns Hopkins University
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Abstract

The SAMI3/ESF (Sami3 is also a model of the ionosphere/equatorial spread $F$) code is used to simulate the growth of equatorial plasma bubbles in the presence of a background wind field based on measured winds. The measured winds exhibit the well-known ‘midnight temperature maximum’ (MTM) pattern, in which an equatorward wind occurs simultaneously with a cessation in the zonal wind. The MTM is often preceded by strong equatorward winds (about 100 m/s). The circumstance where the MTM winds are symmetric across the equator is considered; here the meridional wind component in the southern hemisphere is the reverse of the northern meridional wind. The timing of the wind pattern relative to the imposition of a seed for the ESF instability is explored. We find that the simultaneous occurrence of a seed wave and a strong converging meridional wind pattern can produce post-midnight ESF. We further find that the seed wave and the sudden cessation of the zonal winds can also produce post-midnight ESF. The MENTAT (Magnetic mEridional NeuTrAl Thermospheric) code verifies the occurrence of converging meridional wind patterns such as those simulated here, based on ionosonde data. Results suggest that regional-scale wind measurements would aid in the prediction signal-disrupting ionospheric bubbles.
Aug 2021Published in Space Weather volume 19 issue 8. 10.1029/2021SW002728