Recent advances in ECE imaging performance

Abstract

ECE Imaging (ECEI) systems have been installed and are presently operating on the KSTAR, DIII-D, ASDEX-UG, and HT-7 tokamaks. All are inherently 2-D systems, collect-ing second harmonic ECE radiation to form temporally-resolved localized Te images. System resolutions range from 16 × 8 (HT-7 and ASDEX-UG) to 20 × 16 (DIII-D) to 24 × 16 (KSTAR), with a spatial resolution as low as 1.0 cm (vertical) by 0.9 cm (radial), and with video bandwidths up to 400 kHz. Noise and drift performance of ECEI systems installed on KSTAR and DIII-D were significantly improved in 2011 with new zero bias detectors. This higher level of performance has resulted in new physics advances as ECEI is employed to visualize high temperature plasmas from the plasma edge (pedestal region) through the plasma core, with examples presented herein. In addition to these systems, a new expanded view ECEI system has been developed for the EAST tokamak that produces 24 × 16 Te images from a single imaging array and which is currently being commissioned. © 2012 IOP Publishing Ltd and SISSA.