Solar Multi-Conjugate Adaptive Optics Experiments On The 1.6 Meter Solar Telescope In Big Bear

This project will carry out experiments to study the performance of advanced strategies for adaptive optics, a cutting-edge modern technology that uses fast-moving deformable mirrors to rapidly compensate for the fluctuations in image quality produced by the shimmering atmosphere. Adaptive optics has flourished in recent years, delivering dramatically sharper images but usually only over a rather limited portion of the sky. The technical innovations to be investigated under this program will utilize multiple deformable mirrors optically matched to different layers of the turbulent atmosphere, and this 'multi-conjugate' approach will result in high-quality corrected images over a substantially larger region of the sky.

The adaptive optics system at the 1.6 meter solar telescope at Big Bear, CA, has delivered high-quality solar images in a single-deformable-mirror mode, providing detailed information about complex spatial structures on the surface of the sun at unprecedented spatial scales. The system features three deformable mirrors, each having 357 actuators, and multiple pupil positions in which the deformable mirrors may be placed. When considering the more complex architecture of an adaptive optics system capable of a multi-conjugate observing mode, a number of technical issues have yet to be addressed. These issues include such fundamental questions as the optimum placement in the beam train of deformable mirrors and wavefront sensors. The current project will address these issues directly, experimentally. A number of science goals, including the onset and evolution of solar flares, flare triggering mechanisms, and magnetic reconnection events, require diffraction-limited observations over the large field of view promised by the multi-conjugate observing mode.

In addition to providing training for the next generation of instrumentation scientists, these investigations by their potentially path-finding nature will provide a vital form of broader impacts in advancing the art of adaptive optics at many observatories, for both solar and night-time observations.

Funding for this project is being provided by National Science Foundation 's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.