A high spatial resolution Stokes polarimeter for motional Stark effect imaging

Abstract

We describe an enhanced temporally switched interfero-polarimeter that has been successfully deployed for high spatial resolution motional Stark effect imaging on the KSTAR superconducting tokamak. The system utilizes dual switching ferroelectric liquid crystal waveplates to image the full Stokes vector of elliptically polarized and Doppler-shifted Stark-Zeeman Balmer-alpha emission from high energy neutral beams injected into the magnetized plasma. We describe the optical system and compare its performance against a Mueller matrix model that takes account of non-ideal performance of the switching ferro-electric liquid crystal waveplates and other polarizing components. Show more