Observations of intrinsic toroidal rotation using x-ray crystal spectrometer in aditya-u tokamak

A tangential soft x-ray crystal spectrometer has been designed to observe He-like argon, Ar 16+ , line emission at 3.9494 Å from Aditya-U tokamak plasma using curved crystal and two dimensional CCD detector. In order to simulate possible signal strength of line emission of interest, experiments were conducted to observe externally injected argon impurity in a typical Aditya-U plasma with ~100 kA plasma current and discharge duration of ~ 150 ms. Argon was puffed using Piezo electric valve and its line emissions in the lower ionization stages lying in the visible wavelength range were monitored using high resolution spectrometer CCD system. Simulation using 1-D impurity transport code STRAHL was carried out for Aditya-U plasma parameters and tokamak geometry to obtain emissivity profiles of Ar 16+ line emission. From the experimental and simulation result, it has been deduced that for typical electron temperature of 500 – 1 keV and electron density in the range of 3 – 5 x 10 19 m -3 in Aditya-U plasma, it is expected that Ar 16+ line emission will be confined the region of plasma core. Also, with higher temperature the Ar 16+ line emission will increase.