Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST

S. Ding; A. M. Garofalo; J. Qian; L. Cui; J. T. McClenaghan; C. Pan; J. Chen; X. Zhai; G. McKee; Q. Ren; X. Gong; C. T. Holcomb; W. Guo; L. Lao; J. Ferron; A. Hyatt; G. Staebler; W. Solomon; H. Du; Q. Zang; J. Huang; B. Wan

doi:10.1063/1.4982058

Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST

S. Ding, A. M. Garofalo, J. Qian, L. Cui, J. T. McClenaghan, C. Pan, J. Chen, X. Zhai, G. McKee, Q. Ren, X. Gong, C. T. Holcomb, W. Guo, L. Lao, J. Ferron, A. Hyatt, G. Staebler, W. Solomon, H. Du, Q. ZangJ. Huang, B. Wan

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Abstract

Systematic experimental and modeling investigations on DIII-D show attractive transport properties of fully non-inductive high β_p plasmas. Experiments on DIII-D show that the large-radius internal transport barrier (ITB), a key feature providing excellent confinement in the high β_p regime, is maintained when the scenario is extended from q₉₅ ∼ 12 to 7 and from rapid to near-zero toroidal rotation. The robustness of confinement versus rotation was predicted by gyrofluid modeling showing dominant neoclassical ion energy transport even without the E × B shear effect. The physics mechanism of turbulence suppression, we found, is the Shafranov shift, which is essential and sets a β_p threshold for large-radius ITB formation in the high β_p scenario on DIII-D. This is confirmed by two different parameter-scan experiments, one for a β_N scan and the other for a q₉₅ scan. They both give the same β_p threshold at 1.9 in the experiment. The experimental trend of increasing thermal transport with decreasing β_p is consistent with transport modeling. The progress toward the high β_p scenario on Experimental Advanced Superconducting Tokamak (EAST) is reported. The very first step of extending the high β_p scenario on DIII-D to long pulse on EAST is to establish a long pulse H-mode with ITB on EAST. This paper shows the first 61 s fully non-inductive H-mode with stationary ITB feature and actively cooled ITER-like tungsten divertor in the very recent EAST experiment. The successful use of lower hybrid wave as a key tool to optimize the current profile in the EAST experiment is also introduced. Results show that as the electron density is increased, the fully non-inductive current profile broadens on EAST. The improved understanding and modeling capability are also used to develop advanced scenarios for the China Fusion Engineering Test Reactor. Overall, these results provide encouragement that the high β_p regime can be extended to a lower safety factor and very low rotation, providing a potential path to high performance steady state operation in future devices.

Original language	English
Article number	056114
Journal	Physics of Plasmas
Volume	24
Issue number	5
DOIs	https://doi.org/10.1063/1.4982058
State	Published - May 1 2017
Externally published	Yes

Funding

This work was supported by the National Natural Science Foundation of China under Grant Nos. 11575248, 11305209, 11575246, and 11575249. This work was sponsored in part by National Magnetic Confinement Fusion Science Program of China under Contract Nos. 2015GB103001, 2015GB102004, 2015GB101000, 2015GB110001, and 2015GB110005. This work was also sponsored in part by Youth Innovation Promotion Association Chinese Academy of Sciences (Grant No. 2016384). This work was supported by the U.S. Department of Energy Office of Sciences under Contract No. DE-FC02-04ER54698. DIII-D data shown in this paper can be obtained in digital format by following the links at https://fusion.gat.com/global/D3D_DMP.

Funders	Funder number
National Magnetic Confinement Fusion Science Program of China	2015GB110005, 2015GB102004, 2015GB110001, 2015GB101000, 2015GB103001
Savannah River Operations Office, U.S. Department of Energy	DE-FC02-04ER54698
National Natural Science Foundation of China	11575248, 11575246, 11305209, 11575249
Youth Innovation Promotion Association of the Chinese Academy of Sciences	2016384

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1063/1.4982058

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Ding, S., Garofalo, A. M., Qian, J., Cui, L., McClenaghan, J. T., Pan, C., Chen, J., Zhai, X., McKee, G., Ren, Q., Gong, X., Holcomb, C. T., Guo, W., Lao, L., Ferron, J., Hyatt, A., Staebler, G., Solomon, W., Du, H., ... Wan, B. (2017). Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST. Physics of Plasmas, 24(5), Article 056114. https://doi.org/10.1063/1.4982058

@article{2c74a3ed0965477eb5dba1c8d8781a35,

title = "Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST",

abstract = "Systematic experimental and modeling investigations on DIII-D show attractive transport properties of fully non-inductive high βp plasmas. Experiments on DIII-D show that the large-radius internal transport barrier (ITB), a key feature providing excellent confinement in the high βp regime, is maintained when the scenario is extended from q95 ∼ 12 to 7 and from rapid to near-zero toroidal rotation. The robustness of confinement versus rotation was predicted by gyrofluid modeling showing dominant neoclassical ion energy transport even without the E × B shear effect. The physics mechanism of turbulence suppression, we found, is the Shafranov shift, which is essential and sets a βp threshold for large-radius ITB formation in the high βp scenario on DIII-D. This is confirmed by two different parameter-scan experiments, one for a βN scan and the other for a q95 scan. They both give the same βp threshold at 1.9 in the experiment. The experimental trend of increasing thermal transport with decreasing βp is consistent with transport modeling. The progress toward the high βp scenario on Experimental Advanced Superconducting Tokamak (EAST) is reported. The very first step of extending the high βp scenario on DIII-D to long pulse on EAST is to establish a long pulse H-mode with ITB on EAST. This paper shows the first 61 s fully non-inductive H-mode with stationary ITB feature and actively cooled ITER-like tungsten divertor in the very recent EAST experiment. The successful use of lower hybrid wave as a key tool to optimize the current profile in the EAST experiment is also introduced. Results show that as the electron density is increased, the fully non-inductive current profile broadens on EAST. The improved understanding and modeling capability are also used to develop advanced scenarios for the China Fusion Engineering Test Reactor. Overall, these results provide encouragement that the high βp regime can be extended to a lower safety factor and very low rotation, providing a potential path to high performance steady state operation in future devices.",

author = "S. Ding and Garofalo, {A. M.} and J. Qian and L. Cui and McClenaghan, {J. T.} and C. Pan and J. Chen and X. Zhai and G. McKee and Q. Ren and X. Gong and Holcomb, {C. T.} and W. Guo and L. Lao and J. Ferron and A. Hyatt and G. Staebler and W. Solomon and H. Du and Q. Zang and J. Huang and B. Wan",

note = "Publisher Copyright: {\textcopyright} 2017 Author(s).",

year = "2017",

month = may,

day = "1",

doi = "10.1063/1.4982058",

language = "English",

volume = "24",

journal = "Physics of Plasmas",

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Ding, S, Garofalo, AM, Qian, J, Cui, L, McClenaghan, JT, Pan, C, Chen, J, Zhai, X, McKee, G, Ren, Q, Gong, X, Holcomb, CT, Guo, W, Lao, L, Ferron, J, Hyatt, A, Staebler, G, Solomon, W, Du, H, Zang, Q, Huang, J & Wan, B 2017, 'Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST', Physics of Plasmas, vol. 24, no. 5, 056114. https://doi.org/10.1063/1.4982058

TY - JOUR

T1 - Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST

AU - Ding, S.

AU - Garofalo, A. M.

AU - Qian, J.

AU - Cui, L.

AU - McClenaghan, J. T.

AU - Pan, C.

AU - Chen, J.

AU - Zhai, X.

AU - McKee, G.

AU - Ren, Q.

AU - Gong, X.

AU - Holcomb, C. T.

AU - Guo, W.

AU - Lao, L.

AU - Ferron, J.

AU - Hyatt, A.

AU - Staebler, G.

AU - Solomon, W.

AU - Du, H.

AU - Zang, Q.

AU - Huang, J.

AU - Wan, B.

PY - 2017/5/1

Y1 - 2017/5/1

N2 - Systematic experimental and modeling investigations on DIII-D show attractive transport properties of fully non-inductive high βp plasmas. Experiments on DIII-D show that the large-radius internal transport barrier (ITB), a key feature providing excellent confinement in the high βp regime, is maintained when the scenario is extended from q95 ∼ 12 to 7 and from rapid to near-zero toroidal rotation. The robustness of confinement versus rotation was predicted by gyrofluid modeling showing dominant neoclassical ion energy transport even without the E × B shear effect. The physics mechanism of turbulence suppression, we found, is the Shafranov shift, which is essential and sets a βp threshold for large-radius ITB formation in the high βp scenario on DIII-D. This is confirmed by two different parameter-scan experiments, one for a βN scan and the other for a q95 scan. They both give the same βp threshold at 1.9 in the experiment. The experimental trend of increasing thermal transport with decreasing βp is consistent with transport modeling. The progress toward the high βp scenario on Experimental Advanced Superconducting Tokamak (EAST) is reported. The very first step of extending the high βp scenario on DIII-D to long pulse on EAST is to establish a long pulse H-mode with ITB on EAST. This paper shows the first 61 s fully non-inductive H-mode with stationary ITB feature and actively cooled ITER-like tungsten divertor in the very recent EAST experiment. The successful use of lower hybrid wave as a key tool to optimize the current profile in the EAST experiment is also introduced. Results show that as the electron density is increased, the fully non-inductive current profile broadens on EAST. The improved understanding and modeling capability are also used to develop advanced scenarios for the China Fusion Engineering Test Reactor. Overall, these results provide encouragement that the high βp regime can be extended to a lower safety factor and very low rotation, providing a potential path to high performance steady state operation in future devices.

AB - Systematic experimental and modeling investigations on DIII-D show attractive transport properties of fully non-inductive high βp plasmas. Experiments on DIII-D show that the large-radius internal transport barrier (ITB), a key feature providing excellent confinement in the high βp regime, is maintained when the scenario is extended from q95 ∼ 12 to 7 and from rapid to near-zero toroidal rotation. The robustness of confinement versus rotation was predicted by gyrofluid modeling showing dominant neoclassical ion energy transport even without the E × B shear effect. The physics mechanism of turbulence suppression, we found, is the Shafranov shift, which is essential and sets a βp threshold for large-radius ITB formation in the high βp scenario on DIII-D. This is confirmed by two different parameter-scan experiments, one for a βN scan and the other for a q95 scan. They both give the same βp threshold at 1.9 in the experiment. The experimental trend of increasing thermal transport with decreasing βp is consistent with transport modeling. The progress toward the high βp scenario on Experimental Advanced Superconducting Tokamak (EAST) is reported. The very first step of extending the high βp scenario on DIII-D to long pulse on EAST is to establish a long pulse H-mode with ITB on EAST. This paper shows the first 61 s fully non-inductive H-mode with stationary ITB feature and actively cooled ITER-like tungsten divertor in the very recent EAST experiment. The successful use of lower hybrid wave as a key tool to optimize the current profile in the EAST experiment is also introduced. Results show that as the electron density is increased, the fully non-inductive current profile broadens on EAST. The improved understanding and modeling capability are also used to develop advanced scenarios for the China Fusion Engineering Test Reactor. Overall, these results provide encouragement that the high βp regime can be extended to a lower safety factor and very low rotation, providing a potential path to high performance steady state operation in future devices.

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U2 - 10.1063/1.4982058

DO - 10.1063/1.4982058

M3 - Article

AN - SCOPUS:85019007418

SN - 1070-664X

VL - 24

JO - Physics of Plasmas

JF - Physics of Plasmas

IS - 5

M1 - 056114

ER -

Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST

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