Spectro-polarimetrc optical systems for imaging plasma internal fields, structures and flows

Abstract

Spectro-polarimetric imaging systems have opened new and better ways to study the spatio-temporal behaviour of plasma properties including current distribution, pedestal fields and the velocity distribution function of radiating species from the plasma edge to the core. Using spatial-heterodyne polarimetric techniques, these coherence-imaging (CI) systems have been deployed for motional Stark effect (MSE) imaging and charge-exchange Doppler imaging (CXRS) on KSTAR and ASDEX-Upgrade, and for passive Doppler spectroscopy of the plasma edge on DIII-D and MAST. They have also been used for Doppler imaging of low-temperature argon discharges on the linear mirror device MAGPIE at the ANU, including synchronous Doppler imaging of flow vortices associated with low frequency instabilities. We describe the diagnostic technologies, discuss the results and comparisons with simple models, and consider new applications and future developments. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics.