A numerical study of noontime bite-outs in F2-region electron density

Noontime bite-outs in ionospheric F2-region electron density in the geomagnetic equatorial, low, and middle latitudes have been reproduced in this study using the Thermosphere Ionosphere Electrodynamic General Circulation Model (TIEGCM). The different driv-ing mechanisms of F2-region noontime bite-outs at different latitudes were further verified by modeling simulation. In the geomagnetic equator, the upward ExB plasma drifts are the main process to produce the noontime bite-outs in ionospheric electron density. In the geomagnetic low latitudes, both the electrical fields and poleward meridional winds play a crucial role in forming the noontime bite-outs. In contrast to the case at the geomagnetic equator, a weaker fountain effect might be an favorable condition for the noontime bite-outs to occur at low latitudes. For geomagnetic middle latitudes, an upward plasma flux and poleward meridional winds are the dominated dri-vers in producing the noontime bite-outs. Modeling results show that a large upward plasma flux and poleward meridional winds make the noontime bite-outs to occur and observable over middle latitudes.(c) 2022 COSPAR. Published by Elsevier B.V. All rights reserved.