Inference of Ion-Temperature and Rotation-Velocity Profiles from a Spatially Resolving X-Ray Crystal Spectrometer on Alcator C-Mod
POSTER
Abstract
A new x-ray crystal spectrometer capable of providing spatially ($\sim $1.5 cm) and temporally ($\sim $10 ms) resolved, high resolution spectra of He-like Ar K$\alpha$ lines has been installed on Alcator C-Mod. The imaging spectrometer consists of a spherically bent crystal and three Pilatus II 2d pixel detectors. Spectra are simultaneously measured from 12 -- 45 chords covering the region r/a = 0 - 0.8 with count rates of 0.1 -- 5.0 MHz per chord, enabling measurement with good statistics. Preliminary ion-temperature (T$_{i})$ and rotation-velocity (v$_{\phi })$ profiles are inferred from the Doppler widths and shifts of the chordally integrated spectral lines. The data analysis techniques, T$_{i}$ and v$_{\phi }$ profile results, analysis of background resulting from fusion neutrons, and predictions of performance on ITER and other tokamaks will be presented.
*Research supported by U.S. DOE contract DE-AC02-76-CH03073.