Simulation of Natural and Enhanced Radio Auroras.
Final rept. 31 Jul 70-30 Sep 71,
BATTELLE MEMORIAL INST COLUMBUS OHIO COLUMBUS LABS
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The long-term objective of this program is to develop, from laboratory simulations of the D- and E-regions of the atmosphere, a model to represent the cross section and attenuation effects induced by natural and nuclear-induced auroral formations. The program performed in FY 70 demonstrated the capability developed at Battelles Columbus Laboratories for the scaled simulation of the natural aurora. The present program has as its objective the extension of the capabilities of the FY 70 system to include very intense, overdense auroras, auroras that would decay with time to better represent the radar effects produced by the equivalent of a nuclear-induced aurora. Wide-range enthalpy sweeps permitted the generation of a decaying magnetoactive scaled D-region simulation whose electron density varied from 10 to the 11th power to 10 to the 9th power electronscc. A large portion of the program in FY 71 was devoted to the development of equipment that would survive in the 5000K environment. After considerable effort all systems were extended in capability to permit steady-state operation at the above temperature. Initial forward scatter and back-scatter data were accumulated. A static auroral simulation facility was used to make fine-grain measurements of the buildup of auroral back-scatter for various altitude regimes. For the simulated upper D-region strong backscatter effects due to an auroral electrojet were measured. The cross sections were considerably enhanced as the electrojet level was increased and evidence of nonlinear coupling between modes observed. A theory for the prediction of the cross-section buildup due to an auroral electrojet system is given.
- Atmospheric Physics
- Radiofrequency Wave Propagation