ITER beam aided diagnostics

Abstract

We provide an overview of ITER beam aided diagnostics, including the motional Stark effect (MSE) and charge exchange recombination spectroscopy (CXRS). ITER presents several unique challenges to plasma diagnostics in general and beam-aided diagnostics in particular. The large size, long pulse, and DT operation drives much of the diagnostic design. This in turn has driven a significant R&D effort concerning the maintenance of plasma facing mirrors with sufficient reflectivity to maintain the utility of the diagnostic. In the case of MSE a new approach utilizing spectral splitting will be pursued instead of the conventional polarimetry approach due to the difficulty of maintaining and calibrating the polarizations properties of the plasma facing mirror.

Comparing simulated and experimental spectral line splitting in visible spectroscopy diagnostics in the HL-2A tokamak

“…Now, since the collision cross-section, 〈Q i,j 〉, between beam particles and bulk plasma impurities decreases with beam energy in the range of 50-100 keV amu −1 for hydrogen, here, i stands for a neutral beam particle and j stands for impurities (He, C, W); using a beam with such energies would result in reduced SNR. Therefore, a suitable energy DNB (<50 keV amu −1 , for H) was developed [40,41]. The CX process is shown in equation (1), where the intensity of the spectra is given in equation (2).…”