PROCEEDINGS ARTICLE | August 12, 2009
Proc. SPIE. 7466, Advanced Wavefront Control: Methods, Devices, and Applications VII
KEYWORDS: Calibration, Adaptive optics, Computer simulations, Directed energy weapons, Turbulence, Scintillation, Analytical research, Atmospheric turbulence, Atmospheric propagation, Atmospheric optics
The Atmospheric Turbulence Simulator used in testing in the Atmospheric Simulation and Adaptive-optic Laboratory
Test-bed at Air Force Research Laboratory, Directed Energy Directorate's Starfire Optical Range is
configured based on three characteristics; Fried's parameter, r0, the Rytov number, σ2χ
, and the Greenwood
Frequency, fG. All three may be estimated from open loop data as a means of verifying the simulated turbulence
conditions for a given test configuration. However, unlike r0 and fG, the Rytov number isn't directly calculated.
Instead the scintillation index is estimated from intensity measurements. At low Rytov values, (< 0.3 - 0.4),
this measurement can approximate the Rytov number, however beyond a Rytov of 0.4 this parameter becomes
saturated. Branch Points begin to appear after the Rytov value exceeds 0.1. In this work the behavior of the
branch point density is examined to determine its viability as another parameter for calibration our turbulence
simulator.
