Stokes-Doppler coherence imaging for ITER boundary tomography

Abstract

An optical coherence imaging system is presently being designed for impurity transport studies and other applications on ITER. The wide variation in magnetic field strength and pitch angle (assumed known) across the field of view generates additional Zeeman-polarization-weighting information that can improve the reliability of tomographic reconstructions. Because background reflected light will be somewhat depolarized analysis of only the polarized fraction may be enough to provide a level of background suppression. We present the principles behind these ideas and some simulations that demonstrate how the approach might work on ITER. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization.

Absolute calibration of Doppler coherence imaging velocity images

“…CIS been successfully demonstrated on a number of plasma devices including the linear machine MAGPIE [4], the ASDEX-U tokamak [5], the MAST spherical tokamak [6], and the DIII-D tokamak [7]. Systems are currently being designed for the ITER tokamak [8] and W7-X stellarator [5]. On DIII-D two independent Doppler coherence imaging systems have been developed: a high speed system focused on the lower divertor and a high spatial resolution system that views both upper and lower divertors as well as the main chamber SOL.…”

2D coherence imaging measurements of C2+ ion temperatures in the divertor of Wendelstein 7-X

“…CIS is a relatively new and powerful method [6] to measure two-dimensional images of LOS integrated plasma parameters. The development of CIS diagnostic capabilities is still ongoing in some areas, while in other areas, like flow velocity measurements, it has become a standard diagnostic technique, such as on DIII-D [7], MAST [8], W7-X [9] and is also foreseen on ITER [10]. On W7-X, the 2D particle flow velocity and ion temperature measurements are used to study the 3D island divertor SOL behaviour and to gain a better understanding of the convective particle transport by comparing the diagnostic data with synthetic data generated from full 3D EMC3-Eirene simulations [9].…”

Doppler coherence imaging of scrape-off-layer impurity flows in the HL-2A tokamak

“…19 Stokes-Doppler coherence imaging has been designed as a routine diagnostic for ITER boundary tomography. 31 Doppler coherence imaging technique may be able to be applied to other radiating inhomogeneous media, such as flames, auroras, and plasma thruster.…”