Radiative recombination of atomic oxygen ions in the nighttime F region


  • W. B. Hanson


Hicks and Chubb [1969] have recently reported the nighttime observation of two longitudinal arcs of weak ultraviolet radiation that are rather symmetrically located about the magnetic dip equator. Their photometers, together with an ultraviolet spectrometer of C. A. Barth, were mounted in the polar-orbiting OGO 4 satellite and have identified the radiation as the 1304 A and 1356 A lines of atomic oxygen.

The latitudes of the observed arcs are approximately 15° north and south of the dip equator, and their intensity is of the order of 100 rayleighs. Hicks and Chubb noted that the intensity of the arcs did not correlate with magnetic activity (as given by the Kp index) and stated that the emissions ‘no doubt arise from the same glow as observed with ground-based photometers at 6300 A.’