To elucidate the relationship between electric field and electron-density variations in the high-latitude ionosphere associated with Pc5 ultralow-frequency (ULF) waves from subauroral to high latitudes, we analyzed the global navigation satellite system (GNSS)-total electron content (TEC), ionospheric plasma flow observed by the Super Dual Auroral Radar Network (SuperDARN), and electron density in the inner magnetosphere measured by the Arase satellite. On 23 November 2022, the SuperDARN Prince George (PGR) radar in the dusk sector detected meridional plasma flow oscillations with periods and amplitudes of 5 min and 10–60 m/s, respectively. The plasma flow oscillations began at approximately 01:10 UT and persisted until 03:30 UT over a magnetic latitude range of 65°–72°. The amplitude increased as the magnetic latitude increased. The electron density profile observed by the Arase satellite did not exhibit a sharp gradient during the inner magnetosphere. This indicates that the plasmasphere extended beyond the apogee of the Arase satellite (6.1 Re, where Re is Earth’s radius) under quiet geomagnetic conditions. A detailed comparison between SuperDARN radar and GNSS-TEC data revealed that meridional plasma flow oscillations occurred in the mid-latitude trough and the auroral oval (increased TEC region). Additionally, the equatorward boundary of the auroral oval was located between magnetic latitudes of 72° and 74°. The 15-min detrended TEC measured over the Fort Simpson radar, inside the field-of-view of the PGR radar, showed oscillations similar to the ionospheric plasma flow variations. Through a spectral analysis of the detrended TEC and meridional plasma flow oscillations, we identified a phase difference of ∼135° (∼1.9 min) between them. This phase difference indicates that the upward and downward motion of the ionosphere, driven by an external electric field resulting from Alfvén waves propagating from the dusk-side magnetosphere, was responsible for the observed GNSS-TEC perturbation.