Requirements for detection of ionospheric bubbles in the oxygen recombination EUV airglow

Abstract

We present simulations that show the requirements for the space‐based detection of ionospheric bubbles in the atomic oxygen recombination continuum at 911 Å. In particular, we provide limits to the instrument sensitivity and integration time required for the remote sensing of these diverse and dynamic density depletions that percolate up through the nightside equatorial ionosphere. To first order, these are also the requirements to combine a series of observations and tomographically invert the two‐dimensional structure of the depleted flux tubes. We find that with a sensitivity of 1 count per second per rayleigh, a minimum of 1‐s integration is required to obtain a 3σ detection of the depletion over a 5° zenith angle bin. We compare the results of these simulations with the characteristics of three instruments from the Space Test Program 78–1, Tomographic Experiment using Radiative Recombinative Ionospheric EUV and Radio Sources, and Advanced Research and Global Observation Satellite missions, designed to measure this emission. This comparison shows that the state of the art of ultraviolet remote sensing has advanced to the point where spectrographs can be developed to obtain multidimensional images of bubbles and other similar ionospheric density structures.