High-resolution Tangential AXUV Arrays for Radiated Power Density Measurements on NSTX-U
Authors: L. Delgado-Aparicio, R.E. Bell, I. Faust, K. Tritz, A. Diallo, S.P. Gerhardt, T.A. Kozub, B.P. LeBlanc, and B.C. Stratton
Abstract:Precise measurements of the local radiated power density and total radiated power are a matter of the uttermost importance for understanding the onset of impurity-induced instabilities and the study of particle and heat transport. Accounting of power balance is also needed for the understanding the physics of various divertor con gurations for present and future high-power fusion devices. Poloidal asymmetries in the impurity density can result from high Mach numbers and can impact the assessment of their flux-surface-average and hence vary the estimates of Prad (r, t) and (Zeff); the latter is used in the calculation of the neoclassical conductivity and the interpretation of non-inductive and inductive current fractions. To this end, the bolometric diagnostic in NSTX-U will be upgraded, enhancing the midplane coverage and radial resolution with two tangential views, and adding a new set of poloidally-viewing arrays to measure the 2D radiation distribution. These systems are designed to contribute to the near- and long-term highest priority research goals for NSTX-U which will integrate non-inductive operation at reduced collisionality, with high-pressure, long energy-confinement-times and a divertor solution with metal walls.
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Presented at: the 20th Topical Conference on High Temperature Plasma Diagnostics (HTPD 2014), Atlanta, Georgia, June 1-5, 2014
Submitted to: Review of Scientific Instruments
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Download PPPL-5038 (pdf 2.4 MB; 3 pp)
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