Interpretation of EXCEDE: Spectral and Auroral Infrared Simulation Data.
PHOTOMETRICS INC WOBURN MA
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Nuclear infrared-backgrounds simulation data from excitation of the upper atmosphere by auroral particles and 3 kV electron beams from DNAAFGLs EXCEDE Spectral rocket are analyzed and interpreted. The delay of 2.8 - 3.1 micro radiation output from greater 1BC 11 aurora calculated by a cross-correlation method from aircraft measurements by instruments with footprint less than 1 km has an average value of 2 sec and like the previously-measured energy conversion yields appears to increase with the height of the maximum of the energy deposition rate profile. Fits of radiance data from moving arcs to a simple model of vibrational-bands emission from nitric oxide result in exponential predosing time constants between 1 12 and 2 12 sec, in qualitative agreement with current aerochemistry models. Volume emission rate distributions of the blue-violet air fluorescence within 20 m of EXCEDEs accelerator were unfolded from radiometric photographs taken at characteristic ejection altitudes from onboard. This emission decreases very rapidly away from the rocket, and transverse to the beam axis fits gaussian whose width first increases and then decreases. The measured excitation patterns, which cannot be fully attributed to outgassing from the vehicle, are interpreted in terms of a recent theoretical treatment of discharge initiation and electron heating resulting from an interaction between the charged beam and the local plasma it creates.
- Atmospheric Physics