Stormtime dynamics of the global thermosphere and equatorial ionosphere

Abstract. During magnetic storms the development of equatorial plasma bubbles (EPBs) and distributions of thermospheric densities are strongly influenced by the histories of imposed magnetospheric electric (ε_M) fields. Periods of intense EPB activity driven by penetration ε_M fields in the main phase are followed by their worldwide absence during recovery. A new method is applied to estimate global thermospheric energy (E_th) budgets from orbit-averaged densities measured by accelerometers on polar-orbiting satellites. During the main phase of storms E_th increases as long as the stormtime ε_M operates, then exponentially decays toward quiet-time values during early recovery. Some fraction of the energy deposited at high magnetic latitudes during the main phase propagates into the subauroral ionosphere-thermosphere where it affects chemical and azimuthal-wind dynamics well into recovery. We suggest a scenario wherein fossils of main phase activity inhibit full restoration of quiet-time dayside dynamos and pre-reversal enhancements of upward plasma drifts near dusk denying bottomside irregularities sufficient time to grow into EPBs.