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Proceedings Paper

Hot-air turbulence generator for multiconjugate adaptive optics
Author(s): Onur Keskin; Laurent Jolissaint; Colin Bradley; Sadik Dost; Inna Sharf
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Paper Abstract

In this article, a simple low-cost, statistically repeatable, hot air optical turbulence generator based on the mixing of two air flows with different temperatures is described. Characterization results show that it is possible to create any turbulence strength up to CN2Δh ≈ 6 x 10-10 m1/3, allowing Fried's parameter as small as r0 ≈ 1.7 mm for one crossing through the turbulator or r0 ≈ 1.1 mm for two crossings. Outer scale of (L0 ≈ 133 ± 60 mm) is found to be compatible to the turbulator chamber size (170 mm), and inner scale (l0 ≈ 7.6 mm ± 3.8 mm) compatible with usual values measured by other authors for the free atmosphere. Power spectrum analysis of the centroid of the focused image shows a perfect and accurate agreement with Kolmogorov's theory, allowing to conclude that this device can be used with confidence to emulate good and easily controllable turbulence. In particular, this turbulator will be used with the MCAO test bench developed at the University of Victoria. By allowing two passes of the optical beam through the turbulator, without overlapping, two independent turbulent layers, set at equivalent altitudes of 5 and 15 km above the telescope entrance pupil, will be generated.

Paper Details

Date Published: 11 December 2003
PDF: 9 pages
Proc. SPIE 5162, Advanced Wavefront Control: Methods, Devices, and Applications, (11 December 2003); doi: 10.1117/12.506430
Show Author Affiliations
Onur Keskin, Univ. of Victoria (Canada)
Laurent Jolissaint, Herzberg Institute of Astrophysics/NRC (Canada)
Fonds National de la Recherche Scientifique (Canada)
Colin Bradley, Univ. of Victoria (Canada)
Sadik Dost, Univ. of Victoria (Canada)
Inna Sharf, McGill Univ. (Canada)

Published in SPIE Proceedings Vol. 5162:
Advanced Wavefront Control: Methods, Devices, and Applications
John D. Gonglewski; Mikhail A. Vorontsov; Mark T. Gruneisen, Editor(s)

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