Modeling Equatorial Plasma Bubbles With SAMI3/WACCM-X: September 2017 Storm

We report results from a global simulation of the September 2017 geomagnetic storm. The global model comprises the ionospheric code SAMI3 and the atmosphere/thermosphere code WACCM-X. We show that a train of large-scale EPBs form in the Pacific sector during the storm recovery phase on 8 September 2017. The EPBs are associated with storm-induced modification of the zonal and meridional winds. These changes lead to an eastward electric field which in turn causes an upward E × B drift in the post-midnight sector. A large decrease in the Pedersen conductance caused by meridional equatorward winds leads to an increase in the growth rate of the generalized Rayleigh-Taylor instability that causes EPBs to develop. Interestingly, several EPBs reach altitudes above 3,000 km.