Improved radio tomography of the ionosphere using EUV/optical measurements from satellites

Computerized tomography of the ionosphere employs radio beacons on satellites and ground-based receivers that measure the integrated electron densities along line-of-sight propagation paths. The primary limitation to satellite-based ionospheric radio tomography is the lack of near-horizontal ray paths. This restricts the accuracy for the reconstruction of vertical profiles in the F region. Horizontal integration paths may be obtained using the natural extreme ultraviolet emissions in the ionosphere. The emissions at 91.1 nm are the result of radiative recombination of O⁺ ions and electrons and at 83.4 nm are produced by photoionization of atomic oxygen and subsequent scatter by the atomic oxygen ion. Combining data from radio and EUV measurements yields greatly improved ionospheric density reconstructions. This concept will be tested using the TERRIERS satellite scheduled for launch in early 1998.