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Ann. Geophys., 25, 689-700, 2007
www.ann-geophys.net/25/689/2007/
© European Geosciences Union 2007
On the location and structure of the artificial 630-nm airglow patch over Sura facility
S. M. Grach1,2, M. J. Kosch3,4,5, V. A. Yashnov1, E. N. Sergeev2, M. A. Atroshenko1, and P. V. Kotov1,2
1Radiophysics Faculty, State University of Nizhny Novgorod, Russia
2Radiophysical Research Institute, Nizhny Novgorod, Russia
3Communication Systems, Lancaster University, Lancaster LA1 4WA, UK
4Honorary Research Fellow, University of Kwazulu-Natal, Durban 4001, South Africa
5Currently at Space Vehicles Directorate, Air Force Research Laboratory, Hanscom Air Force Base, MA, USA
Abstract. Results are presented of the artificial optical emission of the atomic oxygen red line
(the radiation of level O(1D) with a wavelength of 630 nm) from the
HF-pumped ionosphere, obtained in September 2004 at the SURA heating facility situated
near Nizhny Novgorod, Russia. For vertical pumping the airglow patch was increasingly
displaced to the north, up to 7–8°, with increasing reflection altitude. For
large brightness of the emission, the airglow patch started to develop at the northern
edge of the pump beam and later expanded to the south. These effects are attributed to
the precipitation of supra-thermal electrons from the pump wave upper hybrid resonance
altitude to lower altitudes where excitation of the O(1D) level is more
effective due to the larger density of atomic oxygen, and the O(1D) lifetime
is shorter. For a pump beam inclination of 12° to the south, the optical spot was
displaced by 4–5° to the south relative to the straight-line projection of the
pump beam onto the sky. This exceeds that expected from the ray tracing and may be
related, most probably, to the so-called "magnetic zenith" effect. In addition,
mid-scale (1–10 km) magnetic field-aligned structures were observed in the pumped
volume of the ionosphere. The east-west motions of the airglow patches are also analyzed.
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