Preliminary experimental evidence of anisotropy of turbulence and the effect of non-Kolmogorov turbulence on wavefront tilt statistics
Preliminary experimental evidence of anisotropy of turbulence and the effect of non-Kolmogorov turbulence on wavefront tilt statistics
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DOI：
10.1117/12.363597
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发表时间：
1999-09
期刊：
影响因子：
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通讯作者：
M. Belen'kii;J. Barchers;S. J. Karis;Christina L. Osmon;J. Brown;R. Fugate
中科院分区：
文献类型：
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作者：
M. Belen'kii;J. Barchers;S. J. Karis;Christina L. Osmon;J. Brown;R. Fugate
我们报告了在新墨西哥州阿尔伯克基Kirtland AFB的Starfire光学距离3.5米望远镜上对北极星进行的波前倾斜测量的初步结果。我们用五个光瞳掩模测量了孔径从0.1m到3.5m的全口径梯度倾斜。利用了两种光学配置。在第一种配置中，在一个相机画面上同时记录了五张北极星的图像。望远镜以其正常的恒星指向模式运行。在第二种配置中，依次更换了瞳孔面具。用螺栓固定望远镜收集了更多的测量数据，以试图减轻山体抖动的影响。倾斜测量的坐标系被旋转，使得X轴和Y轴倾斜分量之间的互相关系数等于零。得到了几个有趣的结果。我们观察到了波前倾斜统计的各向异性。观测到的单轴倾斜方差不相等，水平倾斜方差始终大于垂直倾斜方差。我们认为这些效应是由于非科尔莫戈洛夫湍流对波前倾斜影响的大量证据的各向异性所致。测得的倾斜方差-孔径曲线有一个拐点，超过这个拐点，对于较大的直径，倾斜方差不再减小。在低频段和高频段，倾斜功率谱分别服从f-2/3和f-11/3幂定律。3.5米口径的倾斜时间相关尺度约为0.4秒。
We report preliminary results of wavefront tilt measurements for the star Polaris at the Starfire Optical Range 3.5 m telescope at Kirtland AFB in Albuquerque, NM. We measured full aperture gradient tilt by using five pupil masks representing aperture diameters from 0.1m to 3.5m. Two optical configurations were exploited. In the first configuration, five images of Polaris were recorded simultaneously on one camera frame. The telescope was operated in its normal sidereal pointing mode. In the second configuration, pupil masks were changed sequentially. Additional measurements were collected with the telescope bolted to attempt to mitigate the effects of mont jitter. The coordinate system of the tilt measurement was rotated so that the cross-correlation coefficient between X- and Y-axis tilt components is equal to zero. Several interesting results were obtained. We observed anisotropy of the statistics of wavefront tilt. The observed one-axis tilt variances are unequal and the horizontal tilt variance is consistently greater than the vertical one. We believe these effects dare due to anisotropy of the large evidence of the effects of non-Kolmogorov turbulence on wavefront tilt. The measured tilt variance vs. aperture diameter curve has a knee beyond which the tilt variance no longer decreases for larger diameters. In the low and high frequency range the tilt power spectra obey the f-2/3 and f-11/3 power law, respectively. The tilt temporal correlation scale for the 3.5m aperture is on the order of 0.4 sec.