High-β steady-state scenarios in DIII-D with on-axis current drive

C. C. Petty; J. R. Ferron; F. Turco; J. M. Park; A. M. Garofalo; A. W. Hyatt; G. L. Jackson; T. C. Luce; C. T. Holcomb; E. J. Doyle; W. M. Solomon

High-β steady-state scenarios in DIII-D with on-axis current drive

C. C. Petty
, J. R. Ferron
, F. Turco
, J. M. Park
, A. M. Garofalo
, A. W. Hyatt
, G. L. Jackson
, T. C. Luce
, C. T. Holcomb
, E. J. Doyle
, W. M. Solomon

Fusion Engineering

Research output: Contribution to conference › Paper › peer-review

Abstract

Experiments in the DIII-D tokamak have demonstrated potential new paths to fusion steady state based on peaked current profiles with q_min≈1 that have high ideal stability limits, excellent confinement and benefit from efficient on-axis current drive. In the hybrid scenario, steady-state conditions (V_surf=0) using central ECCD and NBCD are achieved in 1.0 MA discharges with a beta value (β_N=3.6) that is 80%-90% of the ideal n=1 with-wall limit. Interestingly, the hybrid mechanism that anomalously broadens the current profile to maintain q_min>1 and prevents sawteeth continues to function despite the intense central current drive. In the "high ℓ_i" scenario, the combination of broad pressure profile and a peaked current profile tailored to maximize ℓ_i allows β_N≈4.8 and H_98y2≈1.8 to be achieved transiently in a discharge that is overdriven (V_surf<0). The achieved β_N is near the no-wall limit with the idealwall limit higher at β_N≈5-6.

Original language	English
State	Published - 2015
Event	42nd European Physical Society Conference on Plasma Physics, EPS 2015 - Lisbon, Portugal Duration: Jun 22 2015 → Jun 26 2015

Conference

Conference	42nd European Physical Society Conference on Plasma Physics, EPS 2015
Country/Territory	Portugal
City	Lisbon
Period	06/22/15 → 06/26/15

Cite this

@conference{82a83f10b237420eb621e7717c90fd0e,

title = "High-β steady-state scenarios in DIII-D with on-axis current drive",

abstract = "Experiments in the DIII-D tokamak have demonstrated potential new paths to fusion steady state based on peaked current profiles with qmin≈1 that have high ideal stability limits, excellent confinement and benefit from efficient on-axis current drive. In the hybrid scenario, steady-state conditions (Vsurf=0) using central ECCD and NBCD are achieved in 1.0 MA discharges with a beta value (βN=3.6) that is 80\%-90\% of the ideal n=1 with-wall limit. Interestingly, the hybrid mechanism that anomalously broadens the current profile to maintain qmin>1 and prevents sawteeth continues to function despite the intense central current drive. In the {"}high ℓi{"} scenario, the combination of broad pressure profile and a peaked current profile tailored to maximize ℓi allows βN≈4.8 and H98y2≈1.8 to be achieved transiently in a discharge that is overdriven (Vsurf<0). The achieved βN is near the no-wall limit with the idealwall limit higher at βN≈5-6.",

author = "Petty, \{C. C.\} and Ferron, \{J. R.\} and F. Turco and Park, \{J. M.\} and Garofalo, \{A. M.\} and Hyatt, \{A. W.\} and Jackson, \{G. L.\} and Luce, \{T. C.\} and Holcomb, \{C. T.\} and Doyle, \{E. J.\} and Solomon, \{W. M.\}",

year = "2015",

language = "English",

note = "42nd European Physical Society Conference on Plasma Physics, EPS 2015 ; Conference date: 22-06-2015 Through 26-06-2015",

}

TY - CONF

T1 - High-β steady-state scenarios in DIII-D with on-axis current drive

AU - Petty, C. C.

AU - Ferron, J. R.

AU - Turco, F.

AU - Park, J. M.

AU - Garofalo, A. M.

AU - Hyatt, A. W.

AU - Jackson, G. L.

AU - Luce, T. C.

AU - Holcomb, C. T.

AU - Doyle, E. J.

AU - Solomon, W. M.

PY - 2015

Y1 - 2015

N2 - Experiments in the DIII-D tokamak have demonstrated potential new paths to fusion steady state based on peaked current profiles with qmin≈1 that have high ideal stability limits, excellent confinement and benefit from efficient on-axis current drive. In the hybrid scenario, steady-state conditions (Vsurf=0) using central ECCD and NBCD are achieved in 1.0 MA discharges with a beta value (βN=3.6) that is 80%-90% of the ideal n=1 with-wall limit. Interestingly, the hybrid mechanism that anomalously broadens the current profile to maintain qmin>1 and prevents sawteeth continues to function despite the intense central current drive. In the "high ℓi" scenario, the combination of broad pressure profile and a peaked current profile tailored to maximize ℓi allows βN≈4.8 and H98y2≈1.8 to be achieved transiently in a discharge that is overdriven (Vsurf<0). The achieved βN is near the no-wall limit with the idealwall limit higher at βN≈5-6.

AB - Experiments in the DIII-D tokamak have demonstrated potential new paths to fusion steady state based on peaked current profiles with qmin≈1 that have high ideal stability limits, excellent confinement and benefit from efficient on-axis current drive. In the hybrid scenario, steady-state conditions (Vsurf=0) using central ECCD and NBCD are achieved in 1.0 MA discharges with a beta value (βN=3.6) that is 80%-90% of the ideal n=1 with-wall limit. Interestingly, the hybrid mechanism that anomalously broadens the current profile to maintain qmin>1 and prevents sawteeth continues to function despite the intense central current drive. In the "high ℓi" scenario, the combination of broad pressure profile and a peaked current profile tailored to maximize ℓi allows βN≈4.8 and H98y2≈1.8 to be achieved transiently in a discharge that is overdriven (Vsurf<0). The achieved βN is near the no-wall limit with the idealwall limit higher at βN≈5-6.

UR - https://www.scopus.com/pages/publications/84979710730

M3 - Paper

AN - SCOPUS:84979710730

T2 - 42nd European Physical Society Conference on Plasma Physics, EPS 2015

Y2 - 22 June 2015 through 26 June 2015

ER -

High-β steady-state scenarios in DIII-D with on-axis current drive

Abstract

Conference

Other files and links

Fingerprint

Cite this