Progress on turbulence imaging and visualization diagnostics for high temperature plasmas in toroidal devices

摘要

Summary form only given. Diagnostic systems for fluctuation measurements in plasmas have, of necessity, evolved from simple 1-D systems to multi-dimensional systems due to the complexity of turbulence physics of plasmas in toroidal devices illustrated by advanced numerical simulations. Using the significant advancements in millimeter wave imaging technology, Microwave Imaging Reflectometry (MIR) and Electron Cyclotron Emission Imaging (ECEI), capable of simultaneously measuring density and temperature fluctuations are developed. Since both systems require large collection optics for the reflected waves from the "cut-off layer" in the MIR system and vertically (poloidally) extended emissions in ECEI system and since both systems operate in a similar microwave range in most of toroidal devices (e.g. the MIR frequency range is /spl sim/89 GHz and ECEI ranges from 95 to 130 GHz for TEXTOR), it is feasible to combine the two systems which utilize state-of-the-art millimeter-wave planar imaging arrays positioned at the focal point of the detection system to form an image. The detailed testing of the optical system for MIR/ECEI was established with known targets (corrugated metal surfaces). The new 2-D ECE Imaging system (with a total of 128 channels), installed on TEXTOR in December, 2003, combines both techniques to provide a true 2-D imaging of T/sub e/ fluctuation such as "sawtooth crash" near q/spl sim/1 surface. In this paper, a brief review of the imaging diagnostics for turbulence study, combined MIR/ECEI system design description, laboratory testing details of the MIR/ECEI system and multichannel wideband IF technology are presented, together with the progress of subsequent experimental campaigns on TEXTOR plasmas.