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

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.

Ground-layer Adaptive Optics for the 2.5 m Wide-field and High-resolution Solar Telescope

“…However, the available data for measuring the layered turbulence profile at this site are limited. In 2020, (Song et al 2020) built a profiler of the differential solar limb with differential solar limb fluctuations to determine the turbulence profile, and the extended solar limb extends the range of separation angles for a higher resolution of the height profile. They presented the daytime C h n 2 ( ) measurement results of Mt.…”

A Real-Time Measurement System for Atmospheric Turbulence Intensity and Distribution Based on the GLAO System

“…There are currently many methods for measuring atmospheric turbulence in the visible and infrared bands, such as SCIntillation Detection and Ranging (SCIDAR [5]), Stereo-SCIDAR [6][7][8], SLOpe Detection and Ranging (SLODAR [9][10][11][12]), the Multi-Aperture Scintillation Sensor (MASS [13,14]), the Multiple-Aperture Seeing Profiler (MASP [15,16]), the Ring-Image Next-Generation Scintillation Sensor (RINGSS [17]), the Differential Image Motion Monitor (DIMM [18]), Solar DIMM(SDIMM [19][20][21]), S-DIMM+ [22][23][24], and the Profiler of the Differential Solar Limb (PDSL [25]). Most of these numerous algorithms serve the site selection process of large-aperture telescopes by monitoring the atmospheric turbulence at the site for a long time to obtain a comprehensive evaluation of the turbulence situation at the site.…”

Estimating optical turbulence strength using measurements of wavefront distortions

“…Measurements of the vertical profiles of optical turbulence characteristics can be performed using mobile or large-aperture ground-based astronomical telescopes. [2][3][4][5][6][7][8][9] A well-known method for measuring vertical profiles of optical turbulence is the Slodar technique proposed by Wilson R.W.. 10 Slodar method is based on the analysis of cross-correlation functions of small-scale wavefront slopes in crossed optical beams. Another method is Scidar technique.…”