Control of power, torque, and instability drive using in-shot variable neutral beam energy in tokamaks

Pace, D. C.; Collins, C. S.; Crowley, B.; Grierson, B. A.; Heidbrink, W. W.; Pawley, C.; Rauch, J.; Scoville, J. T.; Van Zeeland, M. A.; Zhu, Y. B.

doi:10.1088/0029-5515/57/1/014001

Title: Control of power, torque, and instability drive using in-shot variable neutral beam energy in tokamaks

Journal Article · Wed Sep 28 00:00:00 EDT 2016 · Nuclear Fusion

DOI:https://doi.org/10.1088/0029-5515/57/1/014001· OSTI ID:1364585

Pace, D. C. ^[1]; Collins, C. S. ^[2]; Crowley, B. ^[1]; Grierson, B. A. ^[3]; Heidbrink, W. W. ^[2]; Pawley, C. ^[1]; Rauch, J. ^[1]; Scoville, J. T. ^[1]; Van Zeeland, M. A. ^[1]; Zhu, Y. B. ^[2]

General Atomics, San Diego, CA (United States)
Univ. of California, Irvine, CA (United States)
Princeton Univ., Princeton, NJ (United States)

A first-ever demonstration of controlling power and torque injection through time evolution of neutral beam energy has been achieved in recent experiments at the DIII-D tokamak. Pre-programmed waveforms for the neutral beam energy produce power and torque inputs that can be separately and continuously controlled. Previously, these inputs were tailored using on/off modulation of neutral beams resulting in large perturbations (e.g. power swings of over 1 MW). The new method includes, importantly for experiments, the ability to maintain a fixed injected power while varying the torque. In another case, different beam energy waveforms (in the same plasma conditions) produce significant changes in the observed spectrum of beam ion-driven instabilities. Measurements of beam ion loss show that one energy waveform results in the complete avoidance of coherent losses due to Alfvénic instabilities. This new method of neutral beam operation is intended for further application in a variety of DIII-D experiments including those concerned with high-performance steady state scenarios, fast particle effects, and transport in the low torque regime. As a result, developing this capability would provide similar benefits and improved plasma control for other magnetic confinement fusion facilities.

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Research Organization:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States)

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

Contributing Organization:: The DIII-D Team

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

OSTI ID:: 1364585

Alternate ID(s):: OSTI ID: 1327446; OSTI ID: 1371938; OSTI ID: 1399780

Journal Information:: Nuclear Fusion, Vol. 57, Issue 1; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 18 works

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Cited By (4)

Stellarator Research Opportunities: A Report of the National Stellarator Coordinating Committee Gates, David A.; Anderson, David; Anderson, S. Journal of Fusion Energy, Vol. 37, Issue 1 https://doi.org/10.1007/s10894-018-0152-7	journal	February 2018
Dynamic neutral beam current and voltage control to improve beam efficacy in tokamaks Austin, M. E.; Bardoczi, L.; Collins, C. S. Physics of Plasmas, Vol. 25, Issue 5 https://doi.org/10.1063/1.5016160	journal	May 2018
Active spectroscopy measurements of the deuterium temperature, rotation, and density from the core to scrape off layer on the DIII-D tokamak (invited) Haskey, S. R.; Grierson, B. A.; Stagner, L. Review of Scientific Instruments, Vol. 89, Issue 10 https://doi.org/10.1063/1.5038349	journal	October 2018
Flux-driven nonlinear fluid simulations of ion thermal confinement change by external torque Jhang, Hogun; Kim, S. S. Physics of Plasmas, Vol. 26, Issue 11 https://doi.org/10.1063/1.5120856	journal	November 2019

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