Improved confinement in highly powered high performance scenarios on DIII-D
Abstract
DIII-D has recently shown improved energy confinement by injecting neutral deuterium gas into high performance near-double null divertor (DND) plasmas during high power operation. Representative parameters for these plasmas are: q 95 = 6, P IN up to 15 MW, H 98 = 1.4–1.8, and β N = 2.5–4.0. The ion B ×$$\nabla$$ B direction is away from the primary X-point. While plasma conditions at lower to moderate power input (e.g. ≤11 MW) are shown to be favorable to successful puff-and-pump radiating divertor applications, particularly when using argon seeds, plasma behavior at higher powers (e.g.≥14 MW) may make successful puff-and-pump operation more problematic. In contrast to lower powered high performance plasmas, both τ E and β N in the high power cases (≥14 MW) increased and ELM frequency decreased, as density was raised by deuterium gas injection. Improved performance in the higher power plasmas was tied to higher pedestal pressure, which according to peeling-ballooning mode stability analysis using the ELITE code could increase with density along the kink/peeling stability threshold, while the pedestal pressure gradient in the lower power discharges were limited by the ballooning threshold. This concluded in improved fueling efficiency and ≈10% higher τ E and β N than is normally observed in comparable high performance plasmas on DIII-D. Applying the puff-and-pump radiating divertor approach at moderate versus high power input is shown to result in a much different evolution in core and pedestal plasma behavior. We find that injecting deuterium gas into these highly powered DND plasmas may open up a new avenue for achieving elevated plasma performance, including better fueling, but the resulting higher density may also complicate application of a radiating divertor approach to heat flux reduction in present-day tokamaks, if scenarios involving second-harmonic electron cyclotron heating are used.
- Authors:
-
- General Atomics, San Diego, CA (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Columbia Univ., New York, NY (United States)
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Publication Date:
- Research Org.:
- General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities Division
- OSTI Identifier:
- 1371544
- Alternate Identifier(s):
- OSTI ID: 1527279
- Report Number(s):
- LLNL-JRNL-777844
Journal ID: ISSN 0029-5515
- Grant/Contract Number:
- FC02-04ER54698; AC52-07NA27344; FG02-04ER54761; AC04-94AL85000
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Fusion
- Additional Journal Information:
- Journal Volume: 57; Journal Issue: 8; Journal ID: ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Citation Formats
Petrie, Thomas W., Osborne, Thomas, Fenstermacher, Max E., Ferron, John R., Groebner, Richard J., Grierson, Brian, Holcomb, Christopher T., Lasnier, C., Leonard, Anthony W., Luce, Timothy C., Makowski, Michael A., Turco, Francesca, Solomon, Wayne M., Victor, Brian S., and Watkins, Jonathan G. Improved confinement in highly powered high performance scenarios on DIII-D. United States: N. p., 2017.
Web. doi:10.1088/1741-4326/aa7399.
Petrie, Thomas W., Osborne, Thomas, Fenstermacher, Max E., Ferron, John R., Groebner, Richard J., Grierson, Brian, Holcomb, Christopher T., Lasnier, C., Leonard, Anthony W., Luce, Timothy C., Makowski, Michael A., Turco, Francesca, Solomon, Wayne M., Victor, Brian S., & Watkins, Jonathan G. Improved confinement in highly powered high performance scenarios on DIII-D. United States. https://doi.org/10.1088/1741-4326/aa7399
Petrie, Thomas W., Osborne, Thomas, Fenstermacher, Max E., Ferron, John R., Groebner, Richard J., Grierson, Brian, Holcomb, Christopher T., Lasnier, C., Leonard, Anthony W., Luce, Timothy C., Makowski, Michael A., Turco, Francesca, Solomon, Wayne M., Victor, Brian S., and Watkins, Jonathan G. Fri .
"Improved confinement in highly powered high performance scenarios on DIII-D". United States. https://doi.org/10.1088/1741-4326/aa7399. https://www.osti.gov/servlets/purl/1371544.
@article{osti_1371544,
title = {Improved confinement in highly powered high performance scenarios on DIII-D},
author = {Petrie, Thomas W. and Osborne, Thomas and Fenstermacher, Max E. and Ferron, John R. and Groebner, Richard J. and Grierson, Brian and Holcomb, Christopher T. and Lasnier, C. and Leonard, Anthony W. and Luce, Timothy C. and Makowski, Michael A. and Turco, Francesca and Solomon, Wayne M. and Victor, Brian S. and Watkins, Jonathan G.},
abstractNote = {DIII-D has recently shown improved energy confinement by injecting neutral deuterium gas into high performance near-double null divertor (DND) plasmas during high power operation. Representative parameters for these plasmas are: q 95 = 6, P IN up to 15 MW, H 98 = 1.4–1.8, and β N = 2.5–4.0. The ion B ×$\nabla$ B direction is away from the primary X-point. While plasma conditions at lower to moderate power input (e.g. ≤11 MW) are shown to be favorable to successful puff-and-pump radiating divertor applications, particularly when using argon seeds, plasma behavior at higher powers (e.g.≥14 MW) may make successful puff-and-pump operation more problematic. In contrast to lower powered high performance plasmas, both τ E and β N in the high power cases (≥14 MW) increased and ELM frequency decreased, as density was raised by deuterium gas injection. Improved performance in the higher power plasmas was tied to higher pedestal pressure, which according to peeling-ballooning mode stability analysis using the ELITE code could increase with density along the kink/peeling stability threshold, while the pedestal pressure gradient in the lower power discharges were limited by the ballooning threshold. This concluded in improved fueling efficiency and ≈10% higher τ E and β N than is normally observed in comparable high performance plasmas on DIII-D. Applying the puff-and-pump radiating divertor approach at moderate versus high power input is shown to result in a much different evolution in core and pedestal plasma behavior. We find that injecting deuterium gas into these highly powered DND plasmas may open up a new avenue for achieving elevated plasma performance, including better fueling, but the resulting higher density may also complicate application of a radiating divertor approach to heat flux reduction in present-day tokamaks, if scenarios involving second-harmonic electron cyclotron heating are used.},
doi = {10.1088/1741-4326/aa7399},
journal = {Nuclear Fusion},
number = 8,
volume = 57,
place = {United States},
year = {Fri Jun 09 00:00:00 EDT 2017},
month = {Fri Jun 09 00:00:00 EDT 2017}
}
Free Publicly Available Full Text
Publisher's Version of Record
Other availability
Search WorldCat to find libraries that may hold this journal
Cited by: 18 works
Citation information provided by
Web of Science
Web of Science
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.
Works referenced in this record:
Geometrical properties of a “snowflake” divertor
journal, June 2007
- Ryutov, D. D.
- Physics of Plasmas, Vol. 14, Issue 6
Snowflake divertor configuration studies in National Spherical Torus Experiment
journal, August 2012
- Soukhanovskii, V. A.; Bell, R. E.; Diallo, A.
- Physics of Plasmas, Vol. 19, Issue 8
On heat loading, novel divertors, and fusion reactors
journal, July 2007
- Kotschenreuther, M.; Valanju, P. M.; Mahajan, S. M.
- Physics of Plasmas, Vol. 14, Issue 7
Reduction of divertor heat load in JET ELMy H-modes using impurity seeding techniques
journal, January 2004
- Rapp, J.; Monier-Garbet, P.; Matthews, G. F.
- Nuclear Fusion, Vol. 44, Issue 2
Integrated exhaust control with divertor parameter feedback and pellet ELM pacemaking in ASDEX Upgrade
journal, March 2005
- Kallenbach, A.; Lang, P. T.; Dux, R.
- Journal of Nuclear Materials, Vol. 337-339
Direct measurement of divertor exhaust neon enrichment in DIII-D
journal, February 1997
- Schaffer, M. J.; Wade, M. R.; Maingi, R.
- Journal of Nuclear Materials, Vol. 241-243
Impurity enrichment studies with induced scrape-off layer flow on DIII-D
journal, December 1998
- Wade, M. R.; Hogan, J. T.; Allen, S. L.
- Nuclear Fusion, Vol. 38, Issue 12
Comparison of radiating divertor behaviour in single-null and double-null plasmas in DIII-D
journal, March 2008
- Petrie, T. W.; Brooks, N. H.; Fenstermacher, M. E.
- Nuclear Fusion, Vol. 48, Issue 4
Impurity behaviour under puff-and-pump radiating divertor conditions
journal, May 2009
- Petrie, T. W.; Porter, G. D.; Brooks, N. H.
- Nuclear Fusion, Vol. 49, Issue 6
Compatibility of the radiating divertor with high performance plasmas in DIII-D
journal, June 2007
- Petrie, T. W.; Wade, M. R.; Brooks, N. H.
- Journal of Nuclear Materials, Vol. 363-365
Optimization of DIII-D advanced tokamak discharges with respect to the β limit
journal, May 2005
- Ferron, J. R.; Casper, T. A.; Doyle, E. J.
- Physics of Plasmas, Vol. 12, Issue 5
Application of the radiating divertor approach to innovative tokamak divertor concepts
journal, August 2015
- Petrie, T. W.; Allen, S. L.; Fenstermacher, M. E.
- Journal of Nuclear Materials, Vol. 463
Compatibility of detached divertor operation with robust edge pedestal performance
journal, August 2015
- Leonard, A. W.; Makowski, M. A.; McLean, A. G.
- Journal of Nuclear Materials, Vol. 463
Edge localized modes and the pedestal: A model based on coupled peeling–ballooning modes
journal, May 2002
- Snyder, P. B.; Wilson, H. R.; Ferron, J. R.
- Physics of Plasmas, Vol. 9, Issue 5
Numerical studies of edge localized instabilities in tokamaks
journal, April 2002
- Wilson, H. R.; Snyder, P. B.; Huysmans, G. T. A.
- Physics of Plasmas, Vol. 9, Issue 4
Exploration of the Super H-mode regime on DIII-D and potential advantages for burning plasma devices
journal, March 2016
- Solomon, W. M.; Snyder, P. B.; Bortolon, A.
- Physics of Plasmas, Vol. 23, Issue 5
Results from radiating divertor experiments with RMP ELM suppression and mitigation
journal, May 2011
- Petrie, T. W.; Evans, T. E.; Brooks, N. H.
- Nuclear Fusion, Vol. 51, Issue 7
Works referencing / citing this record:
DIII-D research towards establishing the scientific basis for future fusion reactors
journal, June 2019
- Petty, C. C.
- Nuclear Fusion, Vol. 59, Issue 11
High performance double-null plasmas under radiating divertor and mantle scenarios on DIII-D
journal, July 2019
- Petrie, T. W.; Grierson, B. A.; Osborne, T.
- Nuclear Fusion, Vol. 59, Issue 8