SA25A-1950 - Solar wind Alfven waves coupling to the M-I-T system generating polar cap patches and traveling ionospheric disturbances during geomagnetic storms

Solar wind Alfvén waves [1] coupling to the magnetosphere-ionosphere-thermosphere (M-I-T) have been associated with high-intensity long-duration continuous auroral electrojet activity [2] and shown to modulate ionospheric convection in the cusp generating polar cap patches and atmospheric gravity waves [3,4]. The Resolute Bay Incoherent Scatter Radars (RISR-C and RISR-N) are well suited for observing the ionospheric signatures of flux transfer events and subsequent polar patch formation in the cusp. During geomagnetic storms polar patches are observed as they drift through the field-of-views of RISR and the Canadian High-Arctic Ionospheric Network (CHAIN) ionosondes and GPS receivers. In the ionosphere, the electron density gradients imposed in the cusp, and small-scale irregularities resulting from gradient-drift instability, particularly in the trailing edges of patches, cause GPS TEC and phase variations, and sometimes amplitude scintillation. A byproduct of the coupling process forming polar cap patches are traveling ionospheric irregularities (TIDs). Pulses of ionospheric currents in the cusp that are a source of Joule heating in the lower thermosphere launch atmospheric gravity waves causing medium-to-large-scale TIDs propagating equatorward where they are observed by SuperDARN and in the detrended GPS TEC maps.