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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 and EAST 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 q 95 ~ 12 to 7 and from rapid to near-zero toroidal rotation. The robustness of confinement versus rotation was predicted by gyro fluid modeling showing dominant neoclassical ion energy transport even without 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 β N scan and the other for q 95 scan. They both give the same p threshold at 1.9 in the experiment. Furthermore, the experiment trend of increasing thermal transport with decreasing β p is consistent with transport modeling. The very first step of extending high β p scenario on DIII-D to long pulse on EAST is to establish long pulse H-mode with ITB on EAST. Our paper showsmore » the first 61 sec 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 (LWH) as a key tool to optimize current profile in 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 is also used to develop advanced scenarios for CFETR. These results provide encouragement that the high β p regime can be extended to lower safety factor and very low rotation, providing a potential path to high performance steady state operation in future devices.« less

Authors:
ORCiD logo [1];  [2];  [3];  [4];  [5];  [1];  [1];  [1];  [6]; ORCiD logo [1];  [1];  [7];  [1]; ORCiD logo [2];  [2];  [2]; ORCiD logo [2];  [2];  [1];  [1] more »;  [1]; ORCiD logo [1] « less
  1. Chinese Academy of Sciences (CAS), Beijing (China). Inst. of Plasma Physics
  2. General Atomics, San Diego, CA (United States)
  3. Institute of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei, Anhui 230031, China
  4. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  6. Univ. of Wisconsin, Madison, WI (United States)
  7. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24); National Magnetic Confinement Fusion Science Program of China
OSTI Identifier:
1374574
Alternate Identifier(s):
OSTI ID: 1361849
Grant/Contract Number:  
FC02-04ER54698; 2015GB103001; 2015GB102004; 2015GB101000; 2015GB110001; 2015GB110005; FC02- 04ER54698
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Ding, Siye, 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., Zang, Q., Huang, J., and Wan, B. Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST. United States: N. p., 2017. Web. doi:10.1063/1.4982058.
Ding, Siye, 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., Zang, Q., Huang, J., & Wan, B. Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST. United States. doi:10.1063/1.4982058.
Ding, Siye, 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., Zang, Q., Huang, J., and Wan, B. Wed . "Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST". United States. doi:10.1063/1.4982058. https://www.osti.gov/servlets/purl/1374574.
@article{osti_1374574,
title = {Confinement improvement in the high poloidal beta regime on DIII-D and application to steady-state H-mode on EAST},
author = {Ding, Siye and Garofalo, A. M. and Qian, J. and Cui, L. and McClenaghan, J. T. and Pan, C. and Chen, J. and Zhai, X. and McKee, G. and Ren, Q. and Gong, X. and Holcomb, C. T. and Guo, W. and Lao, L. and Ferron, J. and Hyatt, A. and Staebler, G. and Solomon, W. and Du, H. and Zang, Q. and Huang, J. and Wan, B.},
abstractNote = {Systematic experimental and modeling investigations on DIII-D and EAST 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 gyro fluid modeling showing dominant neoclassical ion energy transport even without 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 βN scan and the other for q95 scan. They both give the same p threshold at 1.9 in the experiment. Furthermore, the experiment trend of increasing thermal transport with decreasing βp is consistent with transport modeling. The very first step of extending high βp scenario on DIII-D to long pulse on EAST is to establish long pulse H-mode with ITB on EAST. Our paper shows the first 61 sec 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 (LWH) as a key tool to optimize current profile in 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 is also used to develop advanced scenarios for CFETR. These results provide encouragement that the high βp regime can be extended to lower safety factor and very low rotation, providing a potential path to high performance steady state operation in future devices.},
doi = {10.1063/1.4982058},
journal = {Physics of Plasmas},
number = 5,
volume = 24,
place = {United States},
year = {Wed May 03 00:00:00 EDT 2017},
month = {Wed May 03 00:00:00 EDT 2017}
}

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