High speed measurements of neutral beam turn-on and impact of beam modulation on measurements of ion density

Grierson, Brian A.; Burrell, Keith H.; Crowley, Brendan J.; Grisham, L.; Scoville, John T.

doi:10.1063/1.4896514

Title: High speed measurements of neutral beam turn-on and impact of beam modulation on measurements of ion density

Journal Article · Thu Oct 02 00:00:00 EDT 2014 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4896514· OSTI ID:1358202

Grierson, Brian A. ^[1]; Burrell, Keith H. ^[2]; Crowley, Brendan J. ^[2]; Grisham, L. ^[1]; Scoville, John T. ^[2]

Princeton Univ., Princeton, NJ (United States). Princeton Plasma Physics Lab.
General Atomics, San Diego, CA (United States)

Modulation of neutral beams on tokamaks is performed routinely, enabling background rejection for active spectroscopic diagnostics, and control of injected power and torque. We nd that there exists an anomalous initial transient in the power delivered to the tokamak that is not accounted for by the accelerator voltage and power supply current. Measurements of the charge-exchange and beam photoemission on the DIII-D tokamak [J.L Luxon, Nucl. Fusion 42, 614 (2002)] at high speed (200 s) reveals that the energy of the beam neutrals are constant, but the density of beam neutrals displays dramatic variation in the rst 2-3 ms following beam turn-on. The impact of this beam density variation on inferred ion densities and impurity transport is presented, with suggested means to correct for the anomalous transient.

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Research Organization:: General Atomics, San Diego, CA (United States)

Sponsoring Organization:: USDOE Office of Nuclear Energy (NE)

Grant/Contract Number:: FC02-04ER54698; AC02-09CH11466

OSTI ID:: 1358202

Alternate ID(s):: OSTI ID: 1367154

Journal Information:: Review of Scientific Instruments, Vol. 85, Issue 10; ISSN 0034-6748

Publisher:: American Institute of Physics (AIP)Copyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 5 works

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References (12)

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Cited By (3)

Validation of the kinetic-turbulent-neoclassical theory for edge intrinsic rotation in DIII-D Ashourvan, Arash; Grierson, B. A.; Battaglia, D. J. Physics of Plasmas, Vol. 25, Issue 5 https://doi.org/10.1063/1.5018326	journal	May 2018
Relative intensity calibration of the DIII-D charge-exchange recombination spectroscopy system using neutral beam injection into gas Grierson, B. A.; Burrell, K. H.; Chrystal, C. Review of Scientific Instruments, Vol. 89, Issue 10 https://doi.org/10.1063/1.5037333	journal	October 2018
Evaluation of impurity densities from charge exchange recombination spectroscopy measurements at ASDEX Upgrade McDermott, R. M.; Dux, R.; Pütterich, T. Plasma Physics and Controlled Fusion, Vol. 60, Issue 9 https://doi.org/10.1088/1361-6587/aad256	journal	July 2018

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