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Title: High fusion performance in Super H-mode experiments on Alcator C-Mod and DIII-D

Abstract

The ‘Super H-Mode’ regime is predicted to enable pedestal height and fusion performance substantially higher than standard H-Mode operation. This regime exists due to a bifurcation of the pedestal pressure, as a function of density, that is predicted by the EPED model to occur in strongly shaped plasmas above a critical pedestal density. Experiments on Alcator C-Mod and DIII-D have achieved access to the Super H-Mode (and Near Super H) regime, and obtained very high pedestal pressure, including the highest achieved on a tokamak (pped ~ 80 kPa) in C-Mod experiments operating near the ITER magnetic field. DIII-D Super H experiments have demonstrated strong performance, including the highest stored energy in the present configuration of DIII-D (W ~ 2.2–3.2 MJ), while utilizing only about half of the available heating power (Pheat ~ 7–12 MW). These DIII-D experiments have obtained the highest value of peak fusion gain, QDT,equiv ~ 0.5, achieved on a medium scale (R < 2 m) tokamak. Sustained high performance operation (βN ~ 2.9, H98 ~ 1.6) has been achieved utilizing n = 3 magnetic perturbations for density and impurity control. Pedestal and global confinement has been maintained in the presence of deuterium and nitrogen gas puffing, whichmore » enables a more radiative divertor condition. A pair of simple performance metrics is developed to assess and compare regimes. Super H-Mode access is predicted for ITER and expected, based on both theoretical prediction and observed normalized performance, to allow ITER to achieve its goals (Q = 10) at Ip < 15 MA, and to potentially enable more compact, cost effective pilot plant and reactor designs.« less

Authors:
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Publication Date:
DOE Contract Number:  
FC02-99ER54512; FC02-04ER54698; FG02-95ER54309; FC02-06ER54873; SC0014264; AC02-09CH11466; SC0017992
Research Org.:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; General Atomics, San Diego, CA (United States); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1882423
DOI:
https://doi.org/10.7910/DVN/EE6CKI

Citation Formats

Snyder, P. B., Hughes, J. W., Osborne, T. H., Paz Soldan, C., Solomon, W. M., Knolker, M., Eldon, D., Evans, T., Golfinopoulos, T., Grierson, B. A., Groebner, R. J., Hubbard, A. E., Kolemen, E., Labombard, B., Laggner, F. M., Meneghini, O., Mordijck, S., Petrie, T., Scott, S., Wang, H. Q., Wilson, H. R., and Zhu, Y. B. High fusion performance in Super H-mode experiments on Alcator C-Mod and DIII-D. United States: N. p., 2021. Web. doi:10.7910/DVN/EE6CKI.
Snyder, P. B., Hughes, J. W., Osborne, T. H., Paz Soldan, C., Solomon, W. M., Knolker, M., Eldon, D., Evans, T., Golfinopoulos, T., Grierson, B. A., Groebner, R. J., Hubbard, A. E., Kolemen, E., Labombard, B., Laggner, F. M., Meneghini, O., Mordijck, S., Petrie, T., Scott, S., Wang, H. Q., Wilson, H. R., & Zhu, Y. B. High fusion performance in Super H-mode experiments on Alcator C-Mod and DIII-D. United States. doi:https://doi.org/10.7910/DVN/EE6CKI
Snyder, P. B., Hughes, J. W., Osborne, T. H., Paz Soldan, C., Solomon, W. M., Knolker, M., Eldon, D., Evans, T., Golfinopoulos, T., Grierson, B. A., Groebner, R. J., Hubbard, A. E., Kolemen, E., Labombard, B., Laggner, F. M., Meneghini, O., Mordijck, S., Petrie, T., Scott, S., Wang, H. Q., Wilson, H. R., and Zhu, Y. B. 2021. "High fusion performance in Super H-mode experiments on Alcator C-Mod and DIII-D". United States. doi:https://doi.org/10.7910/DVN/EE6CKI. https://www.osti.gov/servlets/purl/1882423. Pub date:Wed May 19 00:00:00 EDT 2021
@article{osti_1882423,
title = {High fusion performance in Super H-mode experiments on Alcator C-Mod and DIII-D},
author = {Snyder, P. B. and Hughes, J. W. and Osborne, T. H. and Paz Soldan, C. and Solomon, W. M. and Knolker, M. and Eldon, D. and Evans, T. and Golfinopoulos, T. and Grierson, B. A. and Groebner, R. J. and Hubbard, A. E. and Kolemen, E. and Labombard, B. and Laggner, F. M. and Meneghini, O. and Mordijck, S. and Petrie, T. and Scott, S. and Wang, H. Q. and Wilson, H. R. and Zhu, Y. B.},
abstractNote = {The ‘Super H-Mode’ regime is predicted to enable pedestal height and fusion performance substantially higher than standard H-Mode operation. This regime exists due to a bifurcation of the pedestal pressure, as a function of density, that is predicted by the EPED model to occur in strongly shaped plasmas above a critical pedestal density. Experiments on Alcator C-Mod and DIII-D have achieved access to the Super H-Mode (and Near Super H) regime, and obtained very high pedestal pressure, including the highest achieved on a tokamak (pped ~ 80 kPa) in C-Mod experiments operating near the ITER magnetic field. DIII-D Super H experiments have demonstrated strong performance, including the highest stored energy in the present configuration of DIII-D (W ~ 2.2–3.2 MJ), while utilizing only about half of the available heating power (Pheat ~ 7–12 MW). These DIII-D experiments have obtained the highest value of peak fusion gain, QDT,equiv ~ 0.5, achieved on a medium scale (R < 2 m) tokamak. Sustained high performance operation (βN ~ 2.9, H98 ~ 1.6) has been achieved utilizing n = 3 magnetic perturbations for density and impurity control. Pedestal and global confinement has been maintained in the presence of deuterium and nitrogen gas puffing, which enables a more radiative divertor condition. A pair of simple performance metrics is developed to assess and compare regimes. Super H-Mode access is predicted for ITER and expected, based on both theoretical prediction and observed normalized performance, to allow ITER to achieve its goals (Q = 10) at Ip < 15 MA, and to potentially enable more compact, cost effective pilot plant and reactor designs.},
doi = {10.7910/DVN/EE6CKI},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2021},
month = {5}
}

Works referencing / citing this record:

High fusion performance in Super H-mode experiments on Alcator C-Mod and DIII-D
journal, June 2019