THE LAGOPEDO EXPERIMENTS Morris B. Pongratz, Gordon M. Smith, Henry G. Horak, David J. Simons, C. Dexter Sutherland, John H. Wolcott, and John Zinn The Lagopedo ionospheric depletion experiments conducted with sounding rockets launched from the DoE launch facility in Kauai, Hawaii, represent unique experimental benchmarks for testing the predictions of theoretical codes designed to calculate the ionospheric effects of heavy lift launch vehicles' exhaust gases. Thge experiments were conceived and designed at the DoE's Los Alamos Scientific Laboratory. The rockets were fabricated and launched by the DoE's Sandia Laboratories. The reactive gases were generated by detonating an explosive which was carried to F-region altitudes as the daughter component of a mother-daughter rocket payload configuration. The mother component of the payload carried in situ and total electron content diagnostic packages. To date, the Lagopedo experiments have provided the only existent in situ diagnostics of an artificial ionospheric depletion. Ground-based observations included imaging optics and photometry, ionosonde and total electron content diagnostics, and radar measurements. The recombination of the 0+ ion leads to atomic oxygen in various excited states. The resulting line emissions provide a means of remotely measuring the population of these excited states. This measurement can then be compared with theoretical calculations of the population of excited states. For this particular example we have determined the number of excited atoms along a 1ine-of-sight from the optical ground station. A similar integral has been determined from the theoretical calculations so that a direct comparison is possibl e. The O^D) excited state of oxygen decays by emitting photons at 630.0 nm. This excited state has a lifetime of 110 s. The measured radiance at 630.0-nm deduced from photographic data and photometers was converted to integrated column density of excited states C0(1D)3 by taking the inverse of this time as a rate constant, that is we assumed For purposes of comparison, we have treated two quantities from the data and the theoretical calculation, (1) the maximum column density and (2) the integral of the column density over the observations area, which is equal to the total number of 0(1D). Both of these quantities have similar qualitative behavior for the experimental and the theoretical results. For Lagopedo II, both experimenetally determined quantities increase with a time scale on the order of 100 s and then very slowly decay. The maximum column density falls off with an e-folding time on the order of 1000 s while the integrated column density (total number of excited states) falls off with an e-folding time on the order of 1200 s.
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