Optical auroral conjugacy: Viking UV Imager—South Pole Station ground data

Abstract

High time resolution satellite UV images of the northern auroral oval are compared with South Pole station keogram camera and all‐sky camera observations to determine the displacement of the South Pole conjugate point from its location calculated using the international geomagnetic reference field magnetic field model. The results presented extend the study of optical conjugacy to high magnetic latitudes in a solstice period, and to sunlit auroral events. Three high‐latitude events were analyzed: a poleward expansion, an arc poleward of the midnight oval, and a substantial movement in the afternoon auroral oval. They were determined to occur on closed field lines. A range of displacement for the South Pole conjugate point of 5.3° in latitude and 1.9 hours in MLT was measured.