Studies of EC pre-ionization in DIII-D to support development of ITER plasma initiation

Sinha, Joyeeta; de Vries, P. C.; Walker, M. L.; Battaglia, D. J.; Turco, F.; Hyatt, A.; Kim, H. T.; Stober, J.; Yoneda, R.; Gribov, Y.; Haskey, S. R.; Bykov, I.; Hollmann, E.; Herfindal, J. L.; Glass, F.; Chen, J.; McLean, A.

doi:10.1088/1741-4326/ac59ea

Title: Studies of EC pre-ionization in DIII-D to support development of ITER plasma initiation

Abstract

New experiments have been conducted at DIII-D to improve the physics understanding of plasma initiation assisted by electron cyclotron (EC) wave injection, allowing better extrapolation to ITER. This has been achieved by applying an EC pulse prior to start of the inductive plasma initiation (i.e. the generation of a loop voltage). A pre-plasma was formed during the EC pulse that was characterized in terms of the maximum density and temperature. Parametric scans were performed to study the influence of the EC injected power, EC injection angle, and pre-fill gas pressure on the pre-plasma creation process. These experiments showed that pre-ionized plasma of good quality can have a significant effect on the subsequent V_loop induced plasma initiation process, i.e. a high density pre-plasma, increases the plasma current rise and speed at which ionization is achieved when the V_loop is applied. Here, a good quality pre-plasma is one that achieved a significant degree of ionization, mainly obtained by providing sufficient ECH power in DIII-D of the order of 1 MW. It was found that a minimum EC power of 0.5 MW was required in DIII-D to create ionization, and this would scale to a minimum power of roughly 6.5 MW for ITER.

Authors:

^[1];

^[2]; Walker, M. L. ^[3];

^[4]; Turco, F. ^[5]; Hyatt, A. ^[3]; Kim, H. T. ^[6];

^[7]; Yoneda, R. ^[8]; Gribov, Y. ^[2];

^[2]; Bykov, I. ^[3];

^[9];

^[10]; Glass, F. ^[3]; Chen, J. ^[8]; McLean, A. ^[11]

Tokamak Energy Ltd., Oxfordshire (United Kingdom of Great Britain and Northern Ireland); ITER Organization, St. Paul Lez Durance (France)
ITER Organization, St. Paul Lez Durance (France)
General Atomics, San Diego, CA (United States)
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Columbia Univ., New York, NY (United States)
Culham Science Centre, Abingdon (United Kingdom of Great Britain and Northern Island)
Max-Planck-Inst. für Plasmaphysik, Garching (Germany)
Univ. of California, Los Angeles, CA (United States)
Univ. of California San Diego, La Jolla, CA (United States)
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:: Tue Apr 05 00:00:00 EDT 2022

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

Sponsoring Org.:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

OSTI Identifier:: 1867182

Grant/Contract Number:: FC02-04ER54698; AC02-09CH11466; FG02-04ER54761; SC0019004; FG02-07ER54917; AC05-00OR22725; AC52-07NA27344

Resource Type:: Accepted Manuscript

Journal Name:: Nuclear Fusion

Additional Journal Information:: Journal Volume: 62; Journal Issue: 6; Journal ID: ISSN 0029-5515

Publisher:: IOP Science

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; tokamak; plasma initiation; electron cyclotron waves

Citation Formats


                    Sinha, Joyeeta, de Vries, P. C., Walker, M. L., Battaglia, D. J., Turco, F., Hyatt, A., Kim, H. T., Stober, J., Yoneda, R., Gribov, Y., Haskey, S. R., Bykov, I., Hollmann, E., Herfindal, J. L., Glass, F., Chen, J., and McLean, A. Studies of EC pre-ionization in DIII-D to support development of ITER plasma initiation.  United States: N. p., 2022. 
Web.  doi:10.1088/1741-4326/ac59ea.

Copy to clipboard


                    Sinha, Joyeeta, de Vries, P. C., Walker, M. L., Battaglia, D. J., Turco, F., Hyatt, A., Kim, H. T., Stober, J., Yoneda, R., Gribov, Y., Haskey, S. R., Bykov, I., Hollmann, E., Herfindal, J. L., Glass, F., Chen, J., & McLean, A. Studies of EC pre-ionization in DIII-D to support development of ITER plasma initiation.  United States.  https://doi.org/10.1088/1741-4326/ac59ea

Copy to clipboard


                    Sinha, Joyeeta, de Vries, P. C., Walker, M. L., Battaglia, D. J., Turco, F., Hyatt, A., Kim, H. T., Stober, J., Yoneda, R., Gribov, Y., Haskey, S. R., Bykov, I., Hollmann, E., Herfindal, J. L., Glass, F., Chen, J., and McLean, A. Tue .  
"Studies of EC pre-ionization in DIII-D to support development of ITER plasma initiation".  United States.  https://doi.org/10.1088/1741-4326/ac59ea.  https://www.osti.gov/servlets/purl/1867182.

Copy to clipboard


                    
@article{osti_1867182,

  title        = {Studies of EC pre-ionization in DIII-D to support development of ITER plasma initiation},

  author       = {Sinha, Joyeeta and de Vries, P. C. and Walker, M. L. and Battaglia, D. J. and Turco, F. and Hyatt, A. and Kim, H. T. and Stober, J. and Yoneda, R. and Gribov, Y. and Haskey, S. R. and Bykov, I. and Hollmann, E. and Herfindal, J. L. and Glass, F. and Chen, J. and McLean, A.},

  abstractNote = {New experiments have been conducted at DIII-D to improve the physics understanding of plasma initiation assisted by electron cyclotron (EC) wave injection, allowing better extrapolation to ITER. This has been achieved by applying an EC pulse prior to start of the inductive plasma initiation (i.e. the generation of a loop voltage). A pre-plasma was formed during the EC pulse that was characterized in terms of the maximum density and temperature. Parametric scans were performed to study the influence of the EC injected power, EC injection angle, and pre-fill gas pressure on the pre-plasma creation process. These experiments showed that pre-ionized plasma of good quality can have a significant effect on the subsequent Vloop induced plasma initiation process, i.e. a high density pre-plasma, increases the plasma current rise and speed at which ionization is achieved when the Vloop is applied. Here, a good quality pre-plasma is one that achieved a significant degree of ionization, mainly obtained by providing sufficient ECH power in DIII-D of the order of 1 MW. It was found that a minimum EC power of 0.5 MW was required in DIII-D to create ionization, and this would scale to a minimum power of roughly 6.5 MW for ITER.},

  doi          = {10.1088/1741-4326/ac59ea},

  journal      = {Nuclear Fusion},

  number       = 6,

  volume       = 62,

  place        = {United States},

  year         = {Tue Apr 05 00:00:00 EDT 2022},

  month        = {Tue Apr 05 00:00:00 EDT 2022}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Accepted Manuscript (DOE)

Publisher's Version of Record

https://doi.org/10.1088/1741-4326/ac59ea

Other availability

Search WorldCat to find libraries that may hold this journal

Save / Share:

Export Metadata

Save to My Library

Works referenced in this record:

ECRH-assisted plasma start-up with toroidally inclined launch: multi-machine comparison and perspectives for ITER
journal, July 2011

Stober, J.; Jackson, G. L.; Ascasibar, E.
Nuclear Fusion, Vol. 51, Issue 8
DOI: 10.1088/0029-5515/51/8/083031

Understanding and predicting the dynamics of tokamak discharges during startup and rampdown
journal, May 2010

Jackson, G. L.; Politzer, P. A.; Humphreys, D. A.
Physics of Plasmas, Vol. 17, Issue 5
DOI: 10.1063/1.3374242

Low voltage Ohmic and electron cyclotron heating assisted startup in DIII-D
journal, November 1991

Lloyd, B.; Jackson, G. L.; Taylor, T. S.
Nuclear Fusion, Vol. 31, Issue 11
DOI: 10.1088/0029-5515/31/11/001

Nonlinear collisionless electron cyclotron interaction in the pre-ionisation stage
journal, April 2018

Farina, D.
Nuclear Fusion, Vol. 58, Issue 6
DOI: 10.1088/1741-4326/aabaa7

Low electric field plasma-current start-up in JT-60U
journal, January 1997

Yoshino, R.; Seki, M.
Plasma Physics and Controlled Fusion, Vol. 39, Issue 1
DOI: 10.1088/0741-3335/39/1/012

Electron cyclotron emission radiometer upgrade on the DIII-D tokamak
journal, March 2003

Austin, M. E.; Lohr, J.
Review of Scientific Instruments, Vol. 74, Issue 3
DOI: 10.1063/1.1530387

Wall conditioning in fusion devices with superconducting coils
journal, January 2020

Wauters, T.; Borodin, D.; Brakel, R.
Plasma Physics and Controlled Fusion, Vol. 62, Issue 3
DOI: 10.1088/1361-6587/ab5ad0

ECH pre-ionization and assisted startup in the fully superconducting KSTAR tokamak using second harmonic
journal, December 2008

Bae, Y. S.; Jeong, J. H.; Park, S. I.
Nuclear Fusion, Vol. 49, Issue 2
DOI: 10.1088/0029-5515/49/2/022001

DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
journal, October 2021

Fenstermacher, Max E.; Abrams, Tyler; Barada, Kshitish
Nuclear Fusion
DOI: 10.1088/1741-4326/ac2ff2

ITER breakdown and plasma initiation revisited
journal, August 2019

de Vries, P. C.; Gribov, Y.
Nuclear Fusion, Vol. 59, Issue 9
DOI: 10.1088/1741-4326/ab2ef4

Noninductive plasma initiation and startup in the DIII-D tokamak
journal, July 2011

Jackson, G. L.; Humphreys, D. A.; Hyatt, A. W.
Nuclear Fusion, Vol. 51, Issue 8
DOI: 10.1088/0029-5515/51/8/083015

Phase error correction method for a vibration compensated interferometer
journal, October 2004

Van Zeeland, M. A.; Carlstrom, T. N.
Review of Scientific Instruments, Vol. 75, Issue 10
DOI: 10.1063/1.1786641

Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak
journal, October 2018

Moyer, R. A.; Bykov, I.; Orlov, D. M.
Review of Scientific Instruments, Vol. 89, Issue 10
DOI: 10.1063/1.5038350

Faraday-effect polarimeter diagnostic for internal magnetic field fluctuation measurements in DIII-D
journal, August 2016

Chen, J.; Ding, W. X.; Brower, D. L.
Review of Scientific Instruments, Vol. 87, Issue 11
DOI: 10.1063/1.4960056

Second harmonic electron cyclotron pre-ionization in the DIII-D tokamak
journal, March 2007

Jackson, G. L.; deGrassie, J. S.; Moeller, C. P.
Nuclear Fusion, Vol. 47, Issue 4
DOI: 10.1088/0029-5515/47/4/003

In vessel pressure measurement in nuclear fusion experiments with asdex gauges
journal, September 1998

Haas, G.; Bosch, H-S
Vacuum, Vol. 51, Issue 1
DOI: 10.1016/s0042-207x(98)00131-6

ECRH-assisted start-up in ITER
journal, September 1996

Lloyd, B.; Carolan, P. G.; Warrick, C. D.
Plasma Physics and Controlled Fusion, Vol. 38, Issue 9
DOI: 10.1088/0741-3335/38/9/007

Plasma burn-through simulations using the DYON code and predictions for ITER
journal, November 2013

Kim, Hyun-Tae; Sips, A. C. C.; de Vries, P. C.
Plasma Physics and Controlled Fusion, Vol. 55, Issue 12
DOI: 10.1088/0741-3335/55/12/124032

Similar Records in DOE PAGES and OSTI.GOV collections:

ECH-assisted startup at KSTAR

Journal Article Bae, Y S ; Joung, M ; Yoon, S W ; ... - AIP Conference Proceedings

The electron cyclotron heating (ECH)-assisted startup was successful in the Korea Superconducting Tokamak Advanced Research (KSTAR) first plasma campaign completed in June, 2008. It was observed that the second harmonic EC wave of 0.35 MW was sufficient to achieve breakdown in the ECH pre-ionization phase, to allow burn through, and to sustain the plasma during the current ramp with a low loop voltage of 2.0 V. This corresponds to a toroidal electric field of 0.24 Vm{sup -1} at the innermost vacuum vessel wall (R = 1.3 m). Since there is no feedback control of the plasma radial position in themore »« less
https://doi.org/10.1063/1.3273800
Reducing the L-H transition power threshold in ITER-similar-shape DIII-D hydrogen plasmas

Journal Article Schmitz, Lothar ; Wilcox, Robert S. ; Shiraki, Daisuke ; ... - Nuclear Fusion

Recent dedicated DIII-D experiments in low-torque, ITER-similar-shape (ISS) hydrogen plasmas (at a plasma current I_p ~ 1.5 MA and ITER-similar edge safety factor q₉₅ ~ 3.6) show that the L-H transition power threshold P_LH can be reduced substantially (~30%) with L-mode helium admixtures n_He/n_emore »« less
https://doi.org/10.1088/1741-4326/ac94e1

Full Text Available
The high-β{sub N} hybrid scenario for ITER and FNSF steady-state missions

Journal Article Turco, F. ; Petty, C. C. ; Luce, T. C. ; ... - Physics of Plasmas

New experiments on DIII-D have demonstrated the steady-state potential of the hybrid scenario, with 1 MA of plasma current driven fully non-inductively and β{sub N} up to 3.7 sustained for ∼3 s (∼1.5 current diffusion time, τ{sub R}, in DIII-D), providing the basis for an attractive option for steady-state operation in ITER and FNSF. Excellent confinement is achieved (H{sub 98y2} ∼ 1.6) without performance limiting tearing modes. The hybrid regime overcomes the need for off-axis current drive efficiency, taking advantage of poloidal magnetic flux pumping that is believed to be the result of a saturated 3/2 tearing mode. This allows for efficient currentmore »« less
https://doi.org/10.1063/1.4921161
Comparison between the electron cyclotron current drive experiments on DIII-D and predictions for T-10

Conference Lohr, J ; Harvey, R W ; Luce, T C ; ...

Electron cyclotron current drive has been demonstrated on the DIII-D tokamak in an experiment in which {approximately}1 MW of microwave power generated {approximately}50 kA of non-inductive current. The rf-generated portion was about 15% of the total current. On the T-10 tokamak, more than 3 MW of microwave power will be available for current generation, providing the possibility that all the plasma current could be maintained by this method. Fokker-Planck calculations using the code CQL3D and ray tracing calculations using TORAY have been performed to model both experiments. For DIII-D the agreement between the calculations and measurements is good, producing confidencemore »« less
Full Text Available
60 MHz fast wave current drive experiments for DIII-D

Conference Mayberry, M. J. ; Chiu, S. C. ; Porkolab, M. ; ...

Non-inductive current drive is an essential element of the ITER program because it enhances high fluence nuclear testing during the technology phase of operations. By using fast waves in the ion cyclotron range of frequencies (ICRF), current drive efficiencies comparable to lower-hybrid current drive can be obtained with good penetration of wave power to the high temperature plasma core. An additional advantage of the low frequency scheme is its technological simplicity due to the present availability of efficient, multi-megawatt rf sources in the ICRF. The DIII-D facility provides an excellent opportunity to test the feasibility of the low frequency FWCDmore »« less
https://doi.org/10.1063/1.38507

Full Text Available

Similar Records

Title: Studies of EC pre-ionization in DIII-D to support development of ITER plasma initiation

Abstract

Citation Formats

ECRH-assisted plasma start-up with toroidally inclined launch: multi-machine comparison and perspectives for ITER journal, July 2011

Understanding and predicting the dynamics of tokamak discharges during startup and rampdown journal, May 2010

Low voltage Ohmic and electron cyclotron heating assisted startup in DIII-D journal, November 1991

Nonlinear collisionless electron cyclotron interaction in the pre-ionisation stage journal, April 2018

Low electric field plasma-current start-up in JT-60U journal, January 1997

Electron cyclotron emission radiometer upgrade on the DIII-D tokamak journal, March 2003

Wall conditioning in fusion devices with superconducting coils journal, January 2020

ECH pre-ionization and assisted startup in the fully superconducting KSTAR tokamak using second harmonic journal, December 2008

DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy journal, October 2021

ITER breakdown and plasma initiation revisited journal, August 2019

Noninductive plasma initiation and startup in the DIII-D tokamak journal, July 2011

Phase error correction method for a vibration compensated interferometer journal, October 2004

Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak journal, October 2018

Faraday-effect polarimeter diagnostic for internal magnetic field fluctuation measurements in DIII-D journal, August 2016

Second harmonic electron cyclotron pre-ionization in the DIII-D tokamak journal, March 2007

In vessel pressure measurement in nuclear fusion experiments with asdex gauges journal, September 1998

ECRH-assisted start-up in ITER journal, September 1996

Plasma burn-through simulations using the DYON code and predictions for ITER journal, November 2013

ECRH-assisted plasma start-up with toroidally inclined launch: multi-machine comparison and perspectives for ITER
journal, July 2011

Understanding and predicting the dynamics of tokamak discharges during startup and rampdown
journal, May 2010

Low voltage Ohmic and electron cyclotron heating assisted startup in DIII-D
journal, November 1991

Nonlinear collisionless electron cyclotron interaction in the pre-ionisation stage
journal, April 2018

Low electric field plasma-current start-up in JT-60U
journal, January 1997

Electron cyclotron emission radiometer upgrade on the DIII-D tokamak
journal, March 2003

Wall conditioning in fusion devices with superconducting coils
journal, January 2020

ECH pre-ionization and assisted startup in the fully superconducting KSTAR tokamak using second harmonic
journal, December 2008

DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy
journal, October 2021

ITER breakdown and plasma initiation revisited
journal, August 2019

Noninductive plasma initiation and startup in the DIII-D tokamak
journal, July 2011

Phase error correction method for a vibration compensated interferometer
journal, October 2004

Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak
journal, October 2018

Faraday-effect polarimeter diagnostic for internal magnetic field fluctuation measurements in DIII-D
journal, August 2016

Second harmonic electron cyclotron pre-ionization in the DIII-D tokamak
journal, March 2007

In vessel pressure measurement in nuclear fusion experiments with asdex gauges
journal, September 1998

ECRH-assisted start-up in ITER
journal, September 1996

Plasma burn-through simulations using the DYON code and predictions for ITER
journal, November 2013