P. A. Konyaev

The results of a computer simulation of laser beams focused by a combined multichannel array system in the atmosphere are presented. Beam propagation on atmospheric paths is considered taking into account the influence of turbulence and time-dependent thermal blooming interactions. The increase in the maximum intensity of the focal spot due to the optimization of the initial power density of the emitting aperture is estimated. It is shown that the scaling of the optimal initial power in multichannel arrays preserves the proportional dependence of the maximum intensity in focus with an increase in the number of channels. For wave-optics simulation, custom made software was developed based on the split-step method and modified for parallel algorithms using the functions of the Intel ^® Math Kernel Library.

Complex measurements of atmospheric turbulence level were carried out with the use of a differential turbulence meter, a wavefront sensor, and ultrasonic weather stations. The refractive index structure constant was measured daily along horizontal optical paths at the Basic Experimental Station of the V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences. The comparative analysis of the data received is given.

A technique is proposed for measuring astroclimate characteristics of the Baikal Astrophysical Observatory (BAO) by analysis of the quality of images obtained at a full Sun phase telescope. To estimate the image quality, a modified statistical information “optimal window” algorithm is used. Large amounts of information (thousands of frames) are processed automatically using a hardware-software complex developed at the Institute of Atmospheric Optics based on NVIDIA®CUDA parallel programming technologies and Intel® IPP and MKL libraries. Results of the statistical analysis of solar chromosphere filtergrams in the H-alpha line obtained at BAO during 2001–2002 using a Princeton Instruments 2048B digital camera are presented.

Software for computer simulations of adaptive optics systems for atmospheric laser applications designed on the basis of advanced parallel programming techniques is developed. The adaptive optics system model includes the emitting aperture geometry and beam propagation path scenario, vertical profiles of atmospheric parameters, fast parallel split-step Fourier algorithm for solving wave diffraction and propagation equations, time-dependent models of “frozen” atmospheric turbulence with a wide range of scales, and models of the wavefront sensor and controlled deformable mirror. The hardware system for computer simulations is an off-the-shelf desktop with a 6-core 12-thread Intel® Core™ i7-970 CPU at the maximum frequency of 3.5 GHz and an NVIDIA® GeForce GTX 580 graphic accelerator with 512 universal processors operating at 1.5 GHz. Results of simulations of adaptive imaging and laser beam shaping, aimed at estimating the efficiency of adaptive optics systems on atmospheric paths are presented.