20 years of research on the Alcator C-Mod tokamak

Greenwald, M.; Bader, A.; Baek, Seung Gyou; Bakhtiari, M.; Barnard, Harold; Beck, W.; Bergerson, W.F.; Bespamyatnov, I.O.; Bonoli, P. T.; Brower, D. L.; Brunner, D.; Burke, W.; Candy, J.; Churchill, Michael; Cziegler, I.; Diallo, A.; Dominguez, A.; Duval, B. P.; Edlund, E.; Ennever, P.; Ernst, D. R.; Faust, I.; Fiore, C. L.; Fredian, T.; Garcia, Odd Erik; Gao, C.; Goetz, J. A.; Golfinopoulos, T.; Granetz, R.; Grulke, O.; Hartwig, Zachary; Horne, S.; Howard, N. T.; Hubbard, A.; Hughes, J. W.; Hutchinson, I. H.; Irby, J.; Izzo, V.A.; Kessel, C.; LaBombard, B.; Lau, C.; Li, C.; Lin, Y.; Lipschultz, B.; Loarte, A.; Marmar, E.; Mazurenko, A.; McCracken, G.M.; McDermott, R. M.; Meneghini, O.; Mikkelsen, D. R.; Mossessian, D.; Mumgaard, R.; Myra, J. R.; Nelson‐Melby, E.; Ochoukov, R.; Olynyk, G.M.; Parker, R.; Pitcher, S.; Podpaly, Y.; Porkoláb, M.; Reinke, M.L.; Rice, J.E.; Rowan, W. L.; Schmidt, Andréa; Scott, Steve; Shiraiwa, S.; Sierchio, J. M.; Smick, N.; Snipes, J.; Snyder, P. B.; Sorbom, Brandon; Stillerman, J.; Sung, C.; Takase, Y.; Tang, V.; Terry, J. L.; Terry, D.R.; Theiler, C.; Tronchin-James, A.; Tsujii, N.; Vieira, R.; Walk, J.; Wallace, G.; White, Anne; Whyte, D.G.; Wilson, J. R.; Wolfe, S.; Wright, G.M.; Wright, J. C.; Wukitch, S.; Zweben, S. J.

doi:10.1063/1.4901920

Cited by 99 publications

(73 citation statements)

References 359 publications

(445 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The scans show that I-mode is more stiff than L-mode, I-mode has a lower critical gradient in a=L Ti , and I-mode is closer to marginal stability, similar to the findings for r=a ¼ 0:6. the simulations show that the electron temperature profile stiffness is rather weak in both L-mode and I-mode (contrasted with the ion temperature profile). This result from the simulation is in disagreement with general experimental observations at C-Mod, where the measured electron temperature profile in the core plasma strongly exhibits self-similarity, 40 which is an indication of nearness to marginality, and of high stiffness. The caveat with these simulation results is that the simulations only include ion-scale turbulence.…”

Section: Stiffness Scanscontrasting

confidence: 56%

Nonlinear gyrokinetic simulations of the I-mode high confinement regime and comparisons with experimenta)

et al. 2015

Self Cite

View full text Add to dashboard Cite

For the first time, nonlinear gyrokinetic simulations of I-mode plasmas are performed and compared with experiment. I-mode is a high confinement regime, featuring energy confinement similar to H-mode, but without enhanced particle and impurity particle confinement [D. G. Whyte et al., Nucl. Fusion 50, 105005 (2010)]. As a consequence of the separation between heat and particle transport, I-mode exhibits several favorable characteristics compared to H-mode. The nonlinear gyrokinetic code GYRO [J. Candy and R. E. Waltz, J Comput. Phys. 186, 545 (2003)] is used to explore the effects of E Â B shear and profile stiffness in I-mode and compare with L-mode. The nonlinear GYRO simulations show that I-mode core ion temperature and electron temperature profiles are more stiff than L-mode core plasmas. Scans of the input E Â B shear in GYRO simulations show that E Â B shearing of turbulence is a stronger effect in the core of I-mode than L-mode. The nonlinear simulations match the observed reductions in long wavelength density fluctuation levels across the L-I transition but underestimate the reduction of long wavelength electron temperature fluctuation levels. The comparisons between experiment and gyrokinetic simulations for I-mode suggest that increased E Â B shearing of turbulence combined with increased profile stiffness are responsible for the reductions in core turbulence observed in the experiment, and that I-mode resembles H-mode plasmas more than L-mode plasmas with regards to marginal stability and temperature profile stiffness. V C 2015 AIP Publishing LLC.

show abstract

Section: Stiffness Scanscontrasting

confidence: 56%

Nonlinear gyrokinetic simulations of the I-mode high confinement regime and comparisons with experimenta)

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…The performance of ICRF-heated plasmas was found to be improved with impurity seeding in previous experiments [20]. Contributing to this effect is the reduction of ICRF-specific impurities particularly core Mo concentration and reduced core impurity radiation.…”

Section: B Effects Of Impurity Seedingmentioning

confidence: 87%

“…1(b)-(c)). More detailed descriptions of C-Mod and its ICRF antennas can be found in previous papers [5,[19][20][21]. All discharges in this study were operated in Lmode.…”

Section: Methodsmentioning

confidence: 99%

Characterization of SOL plasma flows and potentials in ICRF-heated plasmas in Alcator C-mod

Hong¹,

Wukitch²,

Lin³

et al. 2017

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

show abstract

“…In this paper, we report on experiments conducted on the Alcator C-Mod tokamak [11][12][13] to determine the radial location of quasi-coherent edge fluctuations in the pedestal using optical diagnostics. The experiments are conducted in ion cyclotron range heated plasmas.…”

Section: Introductionmentioning

confidence: 99%

Radial localization of edge modes in Alcator C-Mod pedestals using optical diagnostics

Theiler

Terry

Edlund

et al. 2017

Plasma Phys. Control. Fusion

View full text Add to dashboard Cite

Dedicated experiments in ion cyclotron range heated Enhanced D-alpha (EDA) H-mode and I-mode plasmas have been performed on Alcator C-Mod to identify the location of edge fluctuations inside the pedestal and to determine their plasma frame phase velocity. For this purpose, measurements from gas puff imaging (GPI) and gas puff charge exchange recombination spectroscopy (GP-CXRS) have been collected using the same optical views. The data suggest that the EDA H-mode-specific quasi-coherent mode (QCM) is centered near the radial electric field (E r ) well minimum and propagates along the ion diamagnetic drift direction in the plasma frame. The weakly coherent mode (WCM) and the geodesic acoustic mode (GAM) observed in I-mode, on the other hand, are found to be located around the outer shear layer of the E r well. This results in a weak plasma frame phase velocity mostly along the electron diamagnetic drift direction for the WCM. The findings in these EDA H-mode plasmas differ from probe measurements in ohmic EDA H-mode [B. LaBombard et al., Phys. Plasmas 21, 056108 (2014)], where the QCM was identified as an electron drift-wave located several mm outside the E r well minimum in a region of positive E r . To explore if instrumental effects of the optical diagnostics could be the cause of the difference, a synthetic diagnostic for GPI is introduced. This diagnostic reproduces amplitude ratios and relative radial shifts of the mode profiles determined from poloidally and toroidally oriented optics and, if instrumental effects related to GP-CXRS are also included, indicates that the measured location of the QCM and WCM relative to the E r well reported here is only weakly affected by instrumental effects.

show abstract

20 years of research on the Alcator C-Mod tokamak

Cited by 99 publications

References 359 publications

Nonlinear gyrokinetic simulations of the I-mode high confinement regime and comparisons with experimenta)

Nonlinear gyrokinetic simulations of the I-mode high confinement regime and comparisons with experimenta)

Characterization of SOL plasma flows and potentials in ICRF-heated plasmas in Alcator C-mod

Radial localization of edge modes in Alcator C-Mod pedestals using optical diagnostics

Contact Info

Product

Resources

About