Articles | Volume 27, issue 5
Ann. Geophys., 27, 2183–2189, 2009

Special issue: 12th International Symposium on Equatorial Aeronomy...

Ann. Geophys., 27, 2183–2189, 2009

  13 May 2009

13 May 2009

Remote Oxygen Sensing by Ionospheric Excitation (ROSIE)

K. S. Kalogerakis1, T. G. Slanger1, E. A. Kendall2,*, T. R. Pedersen3, M. J. Kosch4, B. Gustavsson5, and M. T. Rietveld6 K. S. Kalogerakis et al.
  • 1Molecular Physics Laboratory, SRI International, Menlo Park, CA, USA
  • 2Center for Geospace Studies, SRI International, Menlo Park, CA, USA
  • 3Space Vehicles Directorate, Air Force Research Laboratory, Hanscom AFB, MA, USA
  • 4Communication Systems, Lancaster University, Lancaster, UK
  • 5Department of Physics and Technology, University of Tromsø, Norway
  • 6EISCAT Scientific Association, Ramfjordmoen, Norway
  • *formerly Gerken

Abstract. The principal optical observable emission resulting from ionospheric modification (IM) experiments is the atomic oxygen red line at 630 nm, originating from the O(1D–3P) transition. Because the O(1D) atom has a long radiative lifetime, it is sensitive to collisional relaxation and an observed decay faster than the radiative rate can be attributed to collisions with atmospheric species. In contrast to the common practice of ignoring O-atoms in interpreting such observations in the past, recent experimental studies on the relaxation of O(1D) by O(3P) have revealed the dominant role of oxygen atoms in controlling the lifetime of O(1D) at altitudes relevant to IM experiments. Using the most up-to-date rate coefficients for collisional relaxation of O(1D) by O, N2, and O2, it is now possible to analyze the red line decays observed in IM experiments and thus probe the local ionospheric composition. In this manner, we can demonstrate an approach to remotely detect O-atoms at the altitudes relevant to IM experiments, which we call remote oxygen sensing by ionospheric excitation (ROSIE). The results can be compared with atmospheric models and used to study the temporal, seasonal, altitude and spatial variation of ionospheric O-atom density in the vicinity of heating facilities. We discuss the relevance to atmospheric observations and ionospheric heating experiments and report an analysis of representative IM data.