Proceedings of the NATO Advanced Research Workshop, Lillehammer, Norway, September 20-24, 1988Preface.- Participants.- Electrodynamics of the ionosphere/magnetosphere/ solar wind system at high latitudes.- The formation of isolated magnetic flux tubes on the dayside magnetopause.- Impulsive penetration of solar wind plasma irregularities into the magnetosphere: Relevant laboratory experiments.- Polar rain and the question of direct particle access.- Auroral oval configuration during the quiet condition.- On quantifying the distinctions between the cusp and the cleft/LLBL.- Heating of thermal ions near the equatorward boundary of the mid-altitude polar cleft.- Two-dimensional mapping of dayside convection.- Ionospheric convection in the polar cap as seen by optical imaging.- Balloon observations of electric field over South Pole: Convection patterns.- Ground magnetic perturbations in the polar cap and cleft: Structure and dynamics of ionospheric currents.- ULF pulsations in the polar cusp and cap.- Studies of PclPc3 geomagnetic pulsations at high southern latitudes: Implications for origin and transmission.- Transmission of solar wind hydromagnetic energy into the high latitude magnetosphere.- ELF and VLF waves in the polar clefts and caps.- Pc 15 geomagnetic pulsations and 750 Hz ELF activity at ground level in the northern and southern hemispheres.- Ground magnetic perturbations in the polar cap and cleft: Relationship with the IMF.- Relationships between auroral and magnetic activity in the polar cusp/cleft.- Electrodynamics of auroral and polar cap arcs at very high latitudes.- Simultaneous radar and satellite observations of the polar cusp/cleft at S?ndre Str?mfjord.- The electrodynamic signature of short scale field aligned currents, and associated turbulence in the cusp and dayside auroral zone.- Polar cleft structure at 09 MLT: Coordinated satellite- and ground-based observations.- 6300-A auroral emissions at South Pole: Dayside poleward motion and sun alilS¶