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Dipolarizing flux bundles (DFBs) have been suggested to transport energy and momentum from regions of reconnection in the magnetotail to the high latitude ionosphere, where they can generate localized ionospheric currents that can produce large nighttime geomagnetic disturbances (GMDs). In this study we identified DFBs observed in the midnight sector from ~7 to ~10 RE by THEMIS A, D, and E during days in 2015-2017 whose northern hemisphere magnetic footpoints mapped to regions near Hudson Bay, Canada, and have compared them to isolated GMDs observed by ground magnetometers. We found 6 days during which one or more of these DFBs coincided to within ±3 min with ≥6 nT/s GMDs observed by latitudinally closely spaced ground-based magnetometers located near those footpoints. Spherical elementary current systems (SECS) maps and all-sky imager data provided further characterization of two events, showing short-lived localized intense upward currents, auroral intensifications and/or streamers, and vortical perturbations of a westward electrojet. On all but one of these days the coincident DFB--GMD pairs occurred during intervals of high-speed solar wind streams but low values of SYM/H. The observations reported here indicate that isolated DFBs generated under these conditions influence only limited spatial regions nearer Earth. In some events, in which the DFBs were observed closer to Earth and with lower Earthward velocities, the GMDs occurred slightly earlier than the DFBs, suggesting that braking had begun before the time of the DFB observation. [ABSTRACT FROM AUTHOR]

The response of the total electron content (TEC) of Earth's ionosphere to impulse geomagnetic disturbances, traveling convection vortices (TCVs), is considered in the paper. The data of networks of ground-based magnetometers in Canada and Greenland were used to reveal TCVs, whereas the TEC variations were obtained by processing the data of the IGS and UNAVCO receiving stations of the global positioning system (GPS). Ionospheric disturbances related to TCVs are detected. Using the station network makes it possible to estimate the dynamics of formation and velocity of propagation of the disturbance in space. [ABSTRACT FROM AUTHOR]