Daytime optical turbulence profiling with a profiler of the differential solar limb

• Published in: Monthly notices of the Royal Astronomical Society Vol. 499; no. 2; pp. 1909 - 1917
• Main Authors: Song, Tengfei, Cai, Zhanchuan, Liu, Yu, Zhao, Mingyu, Fang, Yuliang, Zhang, Xuefei, Wang, Jingxing, Li, Xiaobo, Song, Qiwu, Du, Zhimao
• Format: Journal Article
• Language: English
• Published: Oxford University Press 01.12.2020
• Subjects: instrumentation: adaptive optics; site testing; methods: observational; atmospheric effects; techniques: image processing
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/staa2729

ABSTRACT Atmospheric turbulence reduces the image quality and resolution of ground-based optical telescopes. Future large solar telescopes (e.g. the CGST, China Giant Solar Telescope) should be equipped with adaptive optics (AO) systems. The design of AO systems is associated with atmospheric optical turbulence parameters, especially the profile of the refractive index structure $C_{n}^{2}(h)$. With the solar differential image motion monitor (S-DIMM) and the profiler of the moon limb (PML), a simplified version of a PML, termed a profiler of the differential solar limb (PDSL), was built in order to determine the daytime $C_{n}^{2}(h)$ and other atmospheric turbulence parameters. A PDSL with differential solar limb fluctuations was used to determine the turbulence profiling, and the extended solar limb extends the range of separation angles for a higher resolution of the height profile. The PDSL structure and its performance are described. In addition, numerical simulations were conducted to verify the effectiveness of the method. As revealed from the simulation results, the layered integral coefficient matrix is capable of solving the discretization error and enhancing the inversion accuracy of the turbulence contour. The first test results at Mt Wumingshan (a candidate site for the CGST) are presented.