Distinct turbulence sources and confinement features in the spherical tokamak plasma regime
Abstract
New turbulence contributions to plasma transport and confinement in the spherical tokamak (ST) regime are identified through nonlinear gyrokinetic simulations. The drift wave Kelvin-Helmholtz (KH) mode characterized by intrinsic mode asymmetry is shown to drive significant ion thermal transport in strongly rotating national spherical torus experiment (NSTX) L-modes. The long wavelength, quasi-coherent dissipative trapped electron mode (TEM) is destabilized in NSTX H-modes despite the presence of strong E x B shear, providing a robust turbulence source dominant over collisionless TEM. Dissipative trapped electron mode (DTEM)-driven transport in the NSTX parametric regime is shown to increase with electron collision frequency, offering one possible source for the confinement scaling observed in experiments. There exists a turbulence-free regime in the collision-induced collisionless trapped electron mode to DTEM transition for ST plasmas. In conclusion, this predicts a natural access to a minimum transport state in the low collisionality regime that future advanced STs may cover.
- Authors:
-
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Univ. of California, San Diego, CA (United States). La Jolla, CA
- Publication Date:
- Research Org.:
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- OSTI Identifier:
- 1256375
- Alternate Identifier(s):
- OSTI ID: 1238950
- Report Number(s):
- PPPL-5203
Journal ID: ISSN 0029-5515
- Grant/Contract Number:
- AC02-09CH11466; Contract No. DE-AC02-09CH11466
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Fusion
- Additional Journal Information:
- Journal Volume: 55; Journal Issue: 12; Journal ID: ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma turbulence; transport; confinement; spherical tokamak; drift wave; instability; sheared flows
Citation Formats
Wang, W. X., Ethier, S., Ren, Y., Kaye, S., Chen, J., Startsev, E., and Lu, Z. Distinct turbulence sources and confinement features in the spherical tokamak plasma regime. United States: N. p., 2015.
Web. doi:10.1088/0029-5515/55/12/122001.
Wang, W. X., Ethier, S., Ren, Y., Kaye, S., Chen, J., Startsev, E., & Lu, Z. Distinct turbulence sources and confinement features in the spherical tokamak plasma regime. United States. https://doi.org/10.1088/0029-5515/55/12/122001
Wang, W. X., Ethier, S., Ren, Y., Kaye, S., Chen, J., Startsev, E., and Lu, Z. Fri .
"Distinct turbulence sources and confinement features in the spherical tokamak plasma regime". United States. https://doi.org/10.1088/0029-5515/55/12/122001. https://www.osti.gov/servlets/purl/1256375.
@article{osti_1256375,
title = {Distinct turbulence sources and confinement features in the spherical tokamak plasma regime},
author = {Wang, W. X. and Ethier, S. and Ren, Y. and Kaye, S. and Chen, J. and Startsev, E. and Lu, Z.},
abstractNote = {New turbulence contributions to plasma transport and confinement in the spherical tokamak (ST) regime are identified through nonlinear gyrokinetic simulations. The drift wave Kelvin-Helmholtz (KH) mode characterized by intrinsic mode asymmetry is shown to drive significant ion thermal transport in strongly rotating national spherical torus experiment (NSTX) L-modes. The long wavelength, quasi-coherent dissipative trapped electron mode (TEM) is destabilized in NSTX H-modes despite the presence of strong E x B shear, providing a robust turbulence source dominant over collisionless TEM. Dissipative trapped electron mode (DTEM)-driven transport in the NSTX parametric regime is shown to increase with electron collision frequency, offering one possible source for the confinement scaling observed in experiments. There exists a turbulence-free regime in the collision-induced collisionless trapped electron mode to DTEM transition for ST plasmas. In conclusion, this predicts a natural access to a minimum transport state in the low collisionality regime that future advanced STs may cover.},
doi = {10.1088/0029-5515/55/12/122001},
journal = {Nuclear Fusion},
number = 12,
volume = 55,
place = {United States},
year = {Fri Oct 30 00:00:00 EDT 2015},
month = {Fri Oct 30 00:00:00 EDT 2015}
}
Web of Science
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Works referencing / citing this record:
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