Solar flare impacts on ionospheric electrodyamics

In this paper, we use model simulations to investigate possible additional contributions from electrodynamics, finding that the vertical E × B drift in the magnetic equatorial region plays a significant role in the ionosphere response to solar flares. During the initial stage of flares, upward E × B drifts weaken in the magnetic equatorial region, causing a weakened equatorial fountain effect, which in turn causes lowering of the peak height of the F₂ region and depletion of the peak electron density of the F₂ region.

In this initial stage, total electron content (TEC) enhancement is predominantly determined by solar zenith angle control of photoionization. As flares decay, upward E × B drifts are enhanced in the magnetic equatorial region, causing increases of the peak height and density of the F₂ region. This process lasts for several hours, causing a prolonged F₂-region disturbance and TEC enhancement in the magnetic equator region in the aftermath of flares.