Recent Developments in Inverse Problems - Abstract
Saxenhuber, Daniela
Turbulent air motion in the Earth' atmosphere causes index of refraction fluctuations. In atmospheric tomography one aims at reconstructing these atmospheric turbulences from light wavefronts of bright astronomical objects or laser beacons from several directions that are measured on the ground. Therefore, the atmosphere is approximated by several infinitely thin layers which are weighted with the strength of turbulence at the corresponding height. The choice of the number of layers, their heights and weights, is a crucial question for reconstruction quality and speed. Atmospheric tomography is needed in complex Adaptive Optics (AO) systems in large ground-based telescopes. AO is a technology that improves image quality by means of deformable mirrors which correct for atmospheric turbulences in real-time, i.e., at around 500 Hertz. Therefore, fast algorithms which yield a good reconstruction quality on few layers are needed. In this talk, we present a fast iterative algorithm for atmospheric tomography which is based on the Gradient method. Simulation results will be presented in the context of the new generation of Extremely Large Telescopes with mirror diameters of around 40m.