Adaptive optics—glasses of ground-based solar telescope

The sun is the most important object for human. Solar activity has an impact on space weather, earth climate, communication and navigation, etc. By observing the physical processes of the solar atmosphere in space and time scales, and establishing models, we are expected to predict the solar activity and avoid the hazards. The observation based on ground-based large aperture solar telescope is one of the main methods to obtain the high-resolution images of solar activity. Meanwhile, Ground-based high spatial resolution imaging of the Sun is severely limited by wavefront disturbances induced by the Earth's atmosphere turbulence. Therefore, adaptive optics (AO) systems are generally equipped to correct the wavefront disturbances in real time to improve the spectrograph and polarization measurement sensitivity for the large solar telescopes. At present, AO has become an indispensable tool at ground-based solar telescopes for obtaining high-resolution solar images.

  The research team of high-resolution optical imaging of solar activity, under the leadership of Prof. Changhui Rao in Institute of Optics and Electronics (IOE), Chinese Academy of Sciences (CAS), firstly developed solar adaptive optics, ground layer adaptive optics and multi-conjugate adaptive optics in China. Several adaptive optics systems was made for different solar telescopes. Based on New Vacuum Solar Telescope, Yunnan Observatories, CAS, a multi-wavelength simultaneous imaging system contains 7 imaging channels is developed to image the solar atmosphere from the photosphere layer to the chromosphere layer. The achievements of this research team reached the international advanced level, and had important scientific significance for the study of the dynamical origin of solar activity, solar atmosphere model, and application value for the implement of space weather forecasting.

About team
The research team of high-resolution optical imaging of solar atmosphere in IOE has about twenty researchers, including 3 professors, 8 associate professors and researcher assistants, and about 10 students. Their research areas include three aspects: ground based large aperture solar telescopes, adaptive optics and the tomography imaging of solar atmosphere. In the last five years, they were in charge of about 10 projects under the support of the National Natural Science Foundation of China, the National High Technology Research and Development Program of China (863 Program) and other Foundations. Two adaptive optics systems with 37 elements and 151 elements and other experiment systems for ground layer adaptive optics and multi-conjugate adaptive optics were built based on the New Vacuum Solar Telescope, Yunnan Observatories, CAS. More than 50 papers have been published, nearly 30 patents have been authorized by State Intellectual Property Office. The leader of this research team, Rao Changhui, as the vice director of IOE and the Key Laboratory on Adaptive Optics, CAS, is the member of SPIE and OSA. He won the State Technological Invention Award first prize, the State Technological Invention Award second prize two times, and won several provincial-level scientific and technological progress awards.

Rao C H, Zhu L, Zhang L Q, et al. Development of solar adaptive optics[J]. Opto-Electronic Engineering, 2018, 45(3): 170733.