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

Abstract

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.

Authors:

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)

Publication Date:: Wed Sep 28 00:00:00 EDT 2016

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

Sponsoring Org.:: USDOE Office of Nuclear Energy (NE)

Contributing Org.:: The DIII-D Team

OSTI Identifier:: 1364585

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

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

Resource Type:: Accepted Manuscript

Journal Name:: Nuclear Fusion

Additional Journal Information:: Journal Volume: 57; Journal Issue: 1; Journal ID: ISSN 0029-5515

Publisher:: IOP Science

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; neutral beam; tokamak; Alfvén wave; plasma control

Citation Formats


                    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., and Zhu, Y. B. Control of power, torque, and instability drive using in-shot variable neutral beam energy in tokamaks.  United States: N. p., 2016. 
Web.  doi:10.1088/0029-5515/57/1/014001.

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                    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. Control of power, torque, and instability drive using in-shot variable neutral beam energy in tokamaks.  United States.  https://doi.org/10.1088/0029-5515/57/1/014001

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                    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., and Zhu, Y. B. Wed .  
"Control of power, torque, and instability drive using in-shot variable neutral beam energy in tokamaks".  United States.  https://doi.org/10.1088/0029-5515/57/1/014001.  https://www.osti.gov/servlets/purl/1364585.

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@article{osti_1364585,

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

  author       = {Pace, D. C. and Collins, C. S. and Crowley, B. and Grierson, B. A. and Heidbrink, W. W. and Pawley, C. and Rauch, J. and Scoville, J. T. and Van Zeeland, M. A. and Zhu, Y. B.},

  abstractNote = {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.},

  doi          = {10.1088/0029-5515/57/1/014001},

  journal      = {Nuclear Fusion},

  number       = 1,

  volume       = 57,

  place        = {United States},

  year         = {Wed Sep 28 00:00:00 EDT 2016},

  month        = {Wed Sep 28 00:00:00 EDT 2016}

}

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Works referenced in this record:

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Nuclear Fusion, Vol. 42, Issue 5
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DIII-D research to address key challenges for ITER and fusion energy
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Overview of the negative ion based neutral beam injectors for ITER
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Modeling and experimental studies of the DIII-D neutral beam system
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Fusion Engineering and Design, Vol. 96-97
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Confinement degradation by Alfvén-eigenmode induced fast-ion transport in steady-state scenario discharges
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Heidbrink, W. W.; Ferron, J. R.; Holcomb, C. T.
Plasma Physics and Controlled Fusion, Vol. 56, Issue 9
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Fast-ion transport in qmin>2, high- β steady-state scenarios on DIII-Da)
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Major minority: energetic particles in fusion plasmas
journal, March 2011

Breizman, B. N.; Sharapov, S. E.
Plasma Physics and Controlled Fusion, Vol. 53, Issue 5
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Discovery of stationary operation of quiescent H-mode plasmas with net-zero neutral beam injection torque and high energy confinement on DIII-D
journal, March 2016

Burrell, K. H.; Barada, K.; Chen, X.
Physics of Plasmas, Vol. 23, Issue 5
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Fiber optic two-color vibration compensated interferometer for plasma density measurements
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Van Zeeland, M. A.; Boivin, R. L.; Carlstrom, T. N.
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Basic physics of Alfvén instabilities driven by energetic particles in toroidally confined plasmas
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Heidbrink, W. W.
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Scintillator-based diagnostic for fast ion loss measurements on DIII-D
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Explanation of the JET n = 0 chirping mode
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Nuclear Fusion, Vol. 46, Issue 10
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Intense Geodesic Acousticlike Modes Driven by Suprathermal Ions in a Tokamak Plasma
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Nazikian, R.; Fu, G. Y.; Austin, M. E.
Physical Review Letters, Vol. 101, Issue 18
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Beam ion losses due to energetic particle geodesic acoustic modes
journal, November 2012

Fisher, R. K.; Pace, D. C.; Kramer, G. J.
Nuclear Fusion, Vol. 52, Issue 12
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Beams, brightness, and background: Using active spectroscopy techniques for precision measurements in fusion plasma research
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Works referencing / citing this record:

Stellarator Research Opportunities: A Report of the National Stellarator Coordinating Committee
journal, February 2018

Gates, David A.; Anderson, David; Anderson, S.
Journal of Fusion Energy, Vol. 37, Issue 1
DOI: 10.1007/s10894-018-0152-7

Dynamic neutral beam current and voltage control to improve beam efficacy in tokamaks
journal, May 2018

Austin, M. E.; Bardoczi, L.; Collins, C. S.
Physics of Plasmas, Vol. 25, Issue 5
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Active spectroscopy measurements of the deuterium temperature, rotation, and density from the core to scrape off layer on the DIII-D tokamak (invited)
journal, October 2018

Haskey, S. R.; Grierson, B. A.; Stagner, L.
Review of Scientific Instruments, Vol. 89, Issue 10
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Flux-driven nonlinear fluid simulations of ion thermal confinement change by external torque
journal, November 2019

Jhang, Hogun; Kim, S. S.
Physics of Plasmas, Vol. 26, Issue 11
DOI: 10.1063/1.5120856

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

Abstract

Citation Formats

A design retrospective of the DIII-D tokamak journal, May 2002

DIII-D research to address key challenges for ITER and fusion energy journal, July 2015

Overview of the negative ion based neutral beam injectors for ITER journal, February 2016

Modelling neutral beams in fusion devices: Beamlet-based model for fast particle simulations journal, March 2015

Effect of tungsten off-axis accumulation on neutral beam deposition in JET rotating plasmas journal, February 2015

Upgrade of the TCV tokamak, first phase: Neutral beam heating system journal, October 2015

Design of the torus interface for the neutral beam injectors of Wendelstein 7-X journal, November 2015

Real time neutral beam power control on MAST journal, October 2011

Variation of Injected Neutral Beam Power at Constant Particle Energy by Changing the Beam Target Aperture of the TEXTOR Neutral Beam Injectors journal, January 1999

Sawtooth stability in neutral beam heated plasmas in TEXTOR journal, January 2008

Modeling and experimental studies of the DIII-D neutral beam system journal, October 2015

Confinement degradation by Alfvén-eigenmode induced fast-ion transport in steady-state scenario discharges journal, August 2014

Fast-ion transport in qmin>2, high- β steady-state scenarios on DIII-Da) journal, May 2015

Major minority: energetic particles in fusion plasmas journal, March 2011

Discovery of stationary operation of quiescent H-mode plasmas with net-zero neutral beam injection torque and high energy confinement on DIII-D journal, March 2016

Fiber optic two-color vibration compensated interferometer for plasma density measurements journal, October 2006

Basic physics of Alfvén instabilities driven by energetic particles in toroidally confined plasmas journal, May 2008

Scintillator-based diagnostic for fast ion loss measurements on DIII-D journal, October 2010

Explanation of the JET n = 0 chirping mode journal, September 2006

Intense Geodesic Acousticlike Modes Driven by Suprathermal Ions in a Tokamak Plasma journal, October 2008

Beam ion losses due to energetic particle geodesic acoustic modes journal, November 2012

Beams, brightness, and background: Using active spectroscopy techniques for precision measurements in fusion plasma research journal, May 2012

Stellarator Research Opportunities: A Report of the National Stellarator Coordinating Committee journal, February 2018

Dynamic neutral beam current and voltage control to improve beam efficacy in tokamaks 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) journal, October 2018

Flux-driven nonlinear fluid simulations of ion thermal confinement change by external torque journal, November 2019

A design retrospective of the DIII-D tokamak
journal, May 2002

DIII-D research to address key challenges for ITER and fusion energy
journal, July 2015

Overview of the negative ion based neutral beam injectors for ITER
journal, February 2016

Modelling neutral beams in fusion devices: Beamlet-based model for fast particle simulations
journal, March 2015

Effect of tungsten off-axis accumulation on neutral beam deposition in JET rotating plasmas
journal, February 2015

Upgrade of the TCV tokamak, first phase: Neutral beam heating system
journal, October 2015

Design of the torus interface for the neutral beam injectors of Wendelstein 7-X
journal, November 2015

Real time neutral beam power control on MAST
journal, October 2011

Variation of Injected Neutral Beam Power at Constant Particle Energy by Changing the Beam Target Aperture of the TEXTOR Neutral Beam Injectors
journal, January 1999

Sawtooth stability in neutral beam heated plasmas in TEXTOR
journal, January 2008

Modeling and experimental studies of the DIII-D neutral beam system
journal, October 2015

Confinement degradation by Alfvén-eigenmode induced fast-ion transport in steady-state scenario discharges
journal, August 2014

Fast-ion transport in qmin>2, high- β steady-state scenarios on DIII-Da)
journal, May 2015

Major minority: energetic particles in fusion plasmas
journal, March 2011

Discovery of stationary operation of quiescent H-mode plasmas with net-zero neutral beam injection torque and high energy confinement on DIII-D
journal, March 2016

Fiber optic two-color vibration compensated interferometer for plasma density measurements
journal, October 2006

Basic physics of Alfvén instabilities driven by energetic particles in toroidally confined plasmas
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Scintillator-based diagnostic for fast ion loss measurements on DIII-D
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Explanation of the JET n = 0 chirping mode
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