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Title: Multi-device Studies of Pedestal Physics and Confinement in the I-mode Regime

Abstract

This paper describes joint ITPA studies of the I-mode regime, which features an edge thermal barrier but with L-mode-like particle and impurity transport, and without ELMs. The regime has been demonstrated on Alcator C-Mod, ASDEX Upgrade and DIII-D tokamaks, over a wide range of device parameters and pedestal conditions, including low collisionality. Access to I-mode is independent of heating method (neutral beam injection, ICRH and/or ECRH). Normalized energy confinement H98y,2 ≥ 1 has been achieved for a range of 3≤q95≤4.9 and scales favourably with power. Changes in turbulence in the pedestal region accompany the transition from L-mode to I-mode. The L-I threshold increases with plasma density and current, and with device size, but weakly with BT. The upper limit of power for I-modes increases with toroidal field, and is largest on Alcator C-Mod at B > 5 T. Issues for extrapolation to ITER and other future fusion devices are discussed.

Authors:
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Publication Date:
DOE Contract Number:  
FC02-99ER54512; FC02-04ER54698; FG02-94ER54235; AC52-07NA27344; AC02-09CH11466; FG02-89ER53296; FG02-08ER54999; FG02-08ER54984
Research Org.:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of Wisconsin, Madison, WI (United States); Univ. of California, Los Angeles, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE National Nuclear Security Administration (NNSA)
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1882383
DOI:
https://doi.org/10.7910/DVN/JDPLN1

Citation Formats

Hubbard, A. E., Osborne, T., Ryter, F., Gao, X., Ko, J., Orte, L. Barrera, Churchill, R. M., Cziegler, I., Fenstermacher, M., Fischer, R., Gerhardt, S., Groebner, R., Gohil, P., Happel, T., Hughes, J. W., Liu, Z. X., Loarte, A., Maingi, R., Marinoni, A., Marmar, E. S., McDermott, R. M., McKee, G., Rhodes, T., Rice, J. E., Schmitz, L., Theiler, C., Viezzer, E., Walk, J. R., White, A., Whyte, D., Wolfe, S., Wolfrum, E., Yan, Z., Zhang, T., Alcator C-Mod Team, ASDEX Upgrade Team, and DIII-D Team. Multi-device Studies of Pedestal Physics and Confinement in the I-mode Regime. United States: N. p., 2021. Web. doi:10.7910/DVN/JDPLN1.
Hubbard, A. E., Osborne, T., Ryter, F., Gao, X., Ko, J., Orte, L. Barrera, Churchill, R. M., Cziegler, I., Fenstermacher, M., Fischer, R., Gerhardt, S., Groebner, R., Gohil, P., Happel, T., Hughes, J. W., Liu, Z. X., Loarte, A., Maingi, R., Marinoni, A., Marmar, E. S., McDermott, R. M., McKee, G., Rhodes, T., Rice, J. E., Schmitz, L., Theiler, C., Viezzer, E., Walk, J. R., White, A., Whyte, D., Wolfe, S., Wolfrum, E., Yan, Z., Zhang, T., Alcator C-Mod Team, ASDEX Upgrade Team, & DIII-D Team. Multi-device Studies of Pedestal Physics and Confinement in the I-mode Regime. United States. doi:https://doi.org/10.7910/DVN/JDPLN1
Hubbard, A. E., Osborne, T., Ryter, F., Gao, X., Ko, J., Orte, L. Barrera, Churchill, R. M., Cziegler, I., Fenstermacher, M., Fischer, R., Gerhardt, S., Groebner, R., Gohil, P., Happel, T., Hughes, J. W., Liu, Z. X., Loarte, A., Maingi, R., Marinoni, A., Marmar, E. S., McDermott, R. M., McKee, G., Rhodes, T., Rice, J. E., Schmitz, L., Theiler, C., Viezzer, E., Walk, J. R., White, A., Whyte, D., Wolfe, S., Wolfrum, E., Yan, Z., Zhang, T., Alcator C-Mod Team, ASDEX Upgrade Team, and DIII-D Team. 2021. "Multi-device Studies of Pedestal Physics and Confinement in the I-mode Regime". United States. doi:https://doi.org/10.7910/DVN/JDPLN1. https://www.osti.gov/servlets/purl/1882383. Pub date:Thu Apr 01 00:00:00 EDT 2021
@article{osti_1882383,
title = {Multi-device Studies of Pedestal Physics and Confinement in the I-mode Regime},
author = {Hubbard, A. E. and Osborne, T. and Ryter, F. and Gao, X. and Ko, J. and Orte, L. Barrera and Churchill, R. M. and Cziegler, I. and Fenstermacher, M. and Fischer, R. and Gerhardt, S. and Groebner, R. and Gohil, P. and Happel, T. and Hughes, J. W. and Liu, Z. X. and Loarte, A. and Maingi, R. and Marinoni, A. and Marmar, E. S. and McDermott, R. M. and McKee, G. and Rhodes, T. and Rice, J. E. and Schmitz, L. and Theiler, C. and Viezzer, E. and Walk, J. R. and White, A. and Whyte, D. and Wolfe, S. and Wolfrum, E. and Yan, Z. and Zhang, T. and Alcator C-Mod Team and ASDEX Upgrade Team and DIII-D Team},
abstractNote = {This paper describes joint ITPA studies of the I-mode regime, which features an edge thermal barrier but with L-mode-like particle and impurity transport, and without ELMs. The regime has been demonstrated on Alcator C-Mod, ASDEX Upgrade and DIII-D tokamaks, over a wide range of device parameters and pedestal conditions, including low collisionality. Access to I-mode is independent of heating method (neutral beam injection, ICRH and/or ECRH). Normalized energy confinement H98y,2 ≥ 1 has been achieved for a range of 3≤q95≤4.9 and scales favourably with power. Changes in turbulence in the pedestal region accompany the transition from L-mode to I-mode. The L-I threshold increases with plasma density and current, and with device size, but weakly with BT. The upper limit of power for I-modes increases with toroidal field, and is largest on Alcator C-Mod at B > 5 T. Issues for extrapolation to ITER and other future fusion devices are discussed.},
doi = {10.7910/DVN/JDPLN1},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2021},
month = {4}
}

Works referencing / citing this record:

Multi-device studies of pedestal physics and confinement in the I-mode regime
journal, July 2016