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

Journal Article · 04 April 2022 · Nuclear Fusion

DOI: https://doi.org/10.1088/1741-4326/ac59ea · OSTI ID:1867182

^[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); General Atomics, Energy & Advanced Concepts, DIII-D
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)

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.

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

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

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

OSTI ID:: 1867182

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 6 Vol. 62; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (19)

ECRH-assisted plasma start-up with toroidally inclined launch: multi-machine comparison and perspectives for ITER Stober, J.; Jackson, G. L.; Ascasibar, E. Nuclear Fusion, Vol. 51, Issue 8 https://doi.org/10.1088/0029-5515/51/8/083031	journal	July 2011
Nonlinear collisionless electron cyclotron interaction in the pre-ionisation stage Farina, D. Nuclear Fusion, Vol. 58, Issue 6 https://doi.org/10.1088/1741-4326/aabaa7	journal	April 2018
Understanding and predicting the dynamics of tokamak discharges during startup and rampdown Jackson, G. L.; Politzer, P. A.; Humphreys, D. A. Physics of Plasmas, Vol. 17, Issue 5 https://doi.org/10.1063/1.3374242	journal	May 2010
Noninductive plasma initiation and startup in the DIII-D tokamak Jackson, G. L.; Humphreys, D. A.; Hyatt, A. W. Nuclear Fusion, Vol. 51, Issue 8 https://doi.org/10.1088/0029-5515/51/8/083015	journal	July 2011
ECRH-assisted start-up in ITER Lloyd, B.; Carolan, P. G.; Warrick, C. D. Plasma Physics and Controlled Fusion, Vol. 38, Issue 9 https://doi.org/10.1088/0741-3335/38/9/007	journal	September 1996
Wall conditioning in fusion devices with superconducting coils Wauters, T.; Borodin, D.; Brakel, R. Plasma Physics and Controlled Fusion, Vol. 62, Issue 3 https://doi.org/10.1088/1361-6587/ab5ad0	journal	January 2020
In vessel pressure measurement in nuclear fusion experiments with asdex gauges Haas, G.; Bosch, H-S Vacuum, Vol. 51, Issue 1 https://doi.org/10.1016/s0042-207x(98)00131-6	journal	September 1998
Faraday-effect polarimeter diagnostic for internal magnetic field fluctuation measurements in DIII-D Chen, J.; Ding, W. X.; Brower, D. L. Review of Scientific Instruments, Vol. 87, Issue 11 https://doi.org/10.1063/1.4960056	journal	August 2016
Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak Moyer, R. A.; Bykov, I.; Orlov, D. M. Review of Scientific Instruments, Vol. 89, Issue 10 https://doi.org/10.1063/1.5038350	journal	October 2018
Low voltage Ohmic and electron cyclotron heating assisted startup in DIII-D Lloyd, B.; Jackson, G. L.; Taylor, T. S. Nuclear Fusion, Vol. 31, Issue 11 https://doi.org/10.1088/0029-5515/31/11/001	journal	November 1991
Second harmonic electron cyclotron pre-ionization in the DIII-D tokamak Jackson, G. L.; deGrassie, J. S.; Moeller, C. P. Nuclear Fusion, Vol. 47, Issue 4 https://doi.org/10.1088/0029-5515/47/4/003	journal	March 2007
ITER breakdown and plasma initiation revisited de Vries, P. C.; Gribov, Y. Nuclear Fusion, Vol. 59, Issue 9 https://doi.org/10.1088/1741-4326/ab2ef4	journal	August 2019
DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy Fenstermacher, Max E.; Abrams, Tyler; Barada, Kshitish Nuclear Fusion https://doi.org/10.1088/1741-4326/ac2ff2	journal	October 2021
DIII-D Electron Cyclotron Heating System Status and Upgrades Cengher, Mirela; Lohr, John; Gorelov, Yuri IEEE Transactions on Plasma Science, Vol. 44, Issue 12 https://doi.org/10.1109/tps.2016.2571219	journal	December 2016
Plasma burn-through simulations using the DYON code and predictions for ITER Kim, Hyun-Tae; Sips, A. C. C.; de Vries, P. C. Plasma Physics and Controlled Fusion, Vol. 55, Issue 12 https://doi.org/10.1088/0741-3335/55/12/124032	journal	November 2013
Phase error correction method for a vibration compensated interferometer Van Zeeland, M. A.; Carlstrom, T. N. Review of Scientific Instruments, Vol. 75, Issue 10 https://doi.org/10.1063/1.1786641	journal	October 2004
Low electric field plasma-current start-up in JT-60U Yoshino, R.; Seki, M. Plasma Physics and Controlled Fusion, Vol. 39, Issue 1 https://doi.org/10.1088/0741-3335/39/1/012	journal	January 1997
ECH pre-ionization and assisted startup in the fully superconducting KSTAR tokamak using second harmonic Bae, Y. S.; Jeong, J. H.; Park, S. I. Nuclear Fusion, Vol. 49, Issue 2 https://doi.org/10.1088/0029-5515/49/2/022001	journal	December 2008
Electron cyclotron emission radiometer upgrade on the DIII-D tokamak Austin, M. E.; Lohr, J. Review of Scientific Instruments, Vol. 74, Issue 3 https://doi.org/10.1063/1.1530387	journal	March 2003

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