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A long series of polar patches was observed\udby ionosondes and an all-sky imager during a disturbed period (Kp\ud= 7- and IMF Bz < 0). The ionosondes measured electron\uddensities of up to 9 × 1011 m-3 in the patch center, an\udincrease above the density minimum between patches by a factor of \sim4.5. Bands\udof F-region irregularities generated at the equatorward edge of the patches were\udtracked by HF radars. The backscatter bands were swept northward and eastward\udacross the polar cap in a fan-like formation as the afternoon convection cell\udexpanded due to the IMF By > 0. Near the north magnetic\udpole, an all-sky imager observed the 630-nm emission patches of a distinctly\udband-like shape drifting northeastward to eastward. The 630-nm emission patches\udwere associated with the density patches and backscatter bands. The patches\udoriginated in, or near, the cusp footprint where they were formed by convection\udbursts (flow channel events, FCEs) structuring the solar EUV-produced\udphotoionization and the particle-produced auroral/cusp ionization by segmenting\udit into elongated patches. Just equatorward of the cusp footprint Pc5 field line\udresonances (FLRs) were observed by magnetometers, riometers and VHF/HF radars.\udThe AC electric field associated with the FLRs resulted in a\udpoleward-progressing zonal flow pattern and backscatter bands. The VHF radar\udDoppler spectra indicated the presence of steep electron density gradients\udwhich, through the gradient drift instability, can lead to the generation of the\udionospheric irregularities found in patches. The FLRs and FCEs were associated\udwith poleward-progressing DPY currents (Hall currents modulated by the IMF By)\udand riometer absorption enhancements. The temporal and spatial characteristics\udof the VHF backscatter and associated riometer absorptions closely resembled\udthose of poleward moving auroral forms (PMAFs). In the solar wind, IMP 8\udobserved large amplitude Alfvén waves that were correlated with Pc5 pulsations\udobserved by the ground magnetometers, riometers and radars. It is concluded that\udthe FLRs and FCEs that produced patches were driven by solar wind Alfvén waves\udcoupling to the dayside magnetosphere. During a period of southward IMF the\uddawn-dusk electric field associated with the Alfvén waves modulated the\udsubsolar magnetic reconnection into pulses that resulted in convection flow\udbursts mapping to the ionospheric footprint of the cusp. Key words. Ionosphere (polar ionosphere). Magneto-\udspheric physics (magnetosphere-ionosphere interactions; polar wind-magnetosphere\udinteractions)

Observations of polar patches generated by solar wind Alfvén wave coupling to the dayside magnetosphere