Two dimensional radiated power diagnostics on Alcator C-Mod

Journal Article · Wed Oct 15 04:00:00 EDT 2008 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.2965018· OSTI ID:21266624

Reinke, M L; Hutchinson, I H ^[1]

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1. Massachusetts Institute of Technology, 77 Massachusetts Avenue, NW17-225, Cambridge, Massachusetts 02139 (United States)

The radiated power diagnostics for the Alcator C-Mod tokamak have been upgraded to measure two dimensional structure of the photon emissivity profile in order to investigate poloidal asymmetries in the core radiation. Commonly utilized unbiased absolute extreme ultraviolet (AXUV) diode arrays view the plasma along five different horizontal planes. The layout of the diagnostic set is shown and the results from calibrations and recent experiments are discussed. Data showing a significant, 30%-40%, inboard/outboard emissivity asymmetry during ELM-free H-mode are presented. The ability to use AXUV diode arrays to measure absolute radiated power is explored by comparing diode and resistive bolometer-based emissivity profiles for highly radiative L-mode plasmas seeded with argon. Emissivity profiles match in the core but disagree radially outward resulting in an underprediction of P{sub rad} of nearly 50% by the diodes compared to P{sub rad} determined using resistive bolometers.

• OSTI ID: 21266624
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 10 Vol. 79; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ALCATOR DEVICE
ARGON
BOLOMETERS
CALIBRATION
EDGE LOCALIZED MODES
EMISSIVITY
EXTREME ULTRAVIOLET RADIATION
H-MODE PLASMA CONFINEMENT
L-MODE PLASMA CONFINEMENT
PLASMA DIAGNOSTICS
TWO-DIMENSIONAL CALCULATIONS