Modeling the disappearance of equatorial plasma bubble by nighttime medium-scale traveling ionospheric disturbances

  • Nighttime MSTIDs can counteract the growth of EPBs by decreasing the polarization electric fields and background electron density
  • Meridional winds contribute additionally to the disappearance of EPBs
  • EPBs can stretch along with the band structure of MSTIDs, displaying a reverse C shape of EPB
Abstract

The Naval Research Laboratory first-principles ionosphere model SAMI3/ESF is performed to study the interaction between the nighttime medium-scale traveling ionospheric disturbances (MSTIDs) and equatorial plasma bubbles (EPBs). The synthetic dynamo currents are imposed into the potential equation to induce polarization electric fields for generating the MSTIDs. Simulations demonstrate that the MSTIDscan inhibit the upward growth of EPBs; however, MSTIDs alone are insufficient to explain the disappearance of EPBs. We found that the meridional winds likely contribute to the disappearance of MSTIDs by reducing the background electron density and polarization electric fields within the EPBs. Then, the MSTIDs transport plasma to fill the EPB depletions up via E × B drifts. Both MSTIDs and meridional winds are necessary to comprehend the underlying mechanism of EPB disappearance. Additionally, we also found that the zonal and vertical E × B drifts within the MSTIDs affect the morphology of EPBs, leading to a reverse-C shape structure.

Supplementary data

Electron density variations as a function of longitude and altitude for cases 1-3 (case1_ne.mov, case2_ne.mov, case3_ne.mov).

Airglow intensity perturbation variations at an altitude of 250 km as a function of longitude and latitude for cases 1-5 (case1_airglow.mov, case2_airglow.mov, case3_airglow.mov, case4_airglow.mov, case5_airglow.mov).

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