Atmospheric Turbulence and Dynamics of an Adaptive Optics Telescope. Modelling and Analysis

Abstract: To a large extent, the thesis deals with a future solar telescope, the Large Earth-based Solar Telescope (LEST). The dynamical properties of the telescope, in particular its live optics system, have been investigated through implementation of a computer model, which has been used for simulations. The model includes the various parts of the telescope, as well as various image degrading effects. Of the latter, atmospheric turbulence is the most severe one. Modelling of that has therefore been a major part of the thesis work. The first part of the thesis is an introduction to and overview of the thesis subject. That part is followed by six research papers, which treat the subject in more detail. Paper 1 describes the live optics system of the LEST. It also includes a section on the analysis of the dynamic performance of the telescope. Papers 2 and 3 deal with methods for simulating the effects of atmospheric turbulence, including their development over time. The methods allow the effects of several turbulence layers to be superimposed. In Papers 4 and 5, the simulation model is presented. Which subsystems of the telescope that need to be included in the model is discussed, and the implementation of included subsystems is described. The inclusion and implementation of various noise sources is also treated. In Paper 6, results from time-domain simulations carried out using the model are presented. The influence of the image degrading effects are discussed. Using a separately developed state-space model, frequency domain analysis is also included.