| Popis: |
Methodology is presented using observations from a radar and new measurement system to address several fundamental turbulence issues related to laser beam propagation that impact high energy laser (HEL) and laser communication systems. The successful design and operation of these laser systems require high-fidelity realistic laser beam propagation models coupled with a thorough and comprehensive knowledge of the real turbulent atmosphere. To date, modeling and simulation of laser beam propagation through atmospheric turbulence have relied upon a traditional theoretical basis that assumes the existence of homogeneous, isotropic, stationary, and Kolmogorov turbulence. The approach and methodology is discussed to assess the impact of real atmospheric turbulence on laser beam propagation. Analysis will include effects of non-classical turbulence as well as inner (l o ) and outer scale (L o ) effects. Data will be obtained from a new measurement platform using a free-flying balloon that lifts a ring with a boom upon which are mounted fine wire (1μm diameter) sensors to measure high-speed temperature and velocity fluctuations from which the turbulent quantities can be calculated including the refractive index structure parameter (C 2 n ) and the eddy dissipation rate (e). The “ring” is actually 8-sided with a diameter of 30 feet and trails the balloon with several risers. This design eliminates contamination of the balloon wake that plagues conventional systems. |
