First results on modeling of ITER infrared images. (21st January 2016)

• Record Type: Journal Article
• Authors: Kočan, M; Reichle, R; Aumeunier, M-H; Gunn, J P; Kajita, S; Le Guern, F; Lisgo, S W; Loarer, T; Kukushkin, A S; Sashala Naik, A; Rigollet, F; Stratton, B
• Is Part Of: Physica scripta. Volume T167(2016:Feb.)
• Publication Date: 2016-01-21
• Subjects: ITER -- infrared diagnostic -- surface temperature; Physics -- Periodicals; 530.05
• DOI: 10.1088/0031-8949/T167/1/014047
• Languages: English
• ISSNs: 0031-8949

Abstract

Abstract: Infrared (IR) images of the ITER wide angle viewing system are modeled for the baseline plasma equilibrium and partially detached tungsten divertor, taking into account the three-dimensional structure of the first wall and the divertor. The modeling includes a comprehensive chain of calculations from the heat load specifications up to the synthetic, reflection-free IR images of the surface temperature, T surf . The effect of the optical blur due to finite IR detector size and diffraction/aberrations—approximated by a Gaussian filter—on the measured T surf is investigated. The optical blur characterized by σ = 0.7 pixel (approximately twice the diffraction limit) leads to underestimation of T surf, max on the inner vertical divertor target and near the upper X-point by <6% and <4%, respectively. This is within the required measurement accuracy of 10%. Larger underestimation of T surf, max (<12%) is observed on the outer vertical divertor target. The study demonstrates the importance of keeping the performance of the optical system as close as possible to the diffraction limit.