Direct measurement of the electron turbulence-broadening edge transport barrier to facilitate core-edge integration in tokamak fusion plasmas

H. Q. Wang; R. Hong; X. Jian; T. L. Rhodes; H. Y. Guo; A. W. Leonard; X. Ma; J. G. Watkins; J. Ren; B. A. Grierson; M. W. Shafer; F. Scotti; T. H. Osborne; D. M. Thomas; Z. Yan

doi:10.1088/1741-4326/acdfe2

Direct measurement of the electron turbulence-broadening edge transport barrier to facilitate core-edge integration in tokamak fusion plasmas

H. Q. Wang, R. Hong, X. Jian, T. L. Rhodes, H. Y. Guo, A. W. Leonard, X. Ma, J. G. Watkins, J. Ren, B. A. Grierson, M. W. Shafer, F. Scotti, T. H. Osborne, D. M. Thomas, Z. Yan

Advanced Tokamak Physics

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

The integration of a high-performance core and a dissipative divertor, or the so-called ‘core-edge integration,’ has been widely identified as a critical gap in the design of future fusion reactors. In this letter, we report, for the first time, direct experimental evidence of electron turbulence at the DIII-D H-mode pedestal that correlates with the broadening of the pedestal and thus facilitates core-edge integration. In agreement with gyrokinetic simulations, this electron turbulence is enhanced by high η _e (η _e = L_n /L_T_e, where L_n is the density scale length and L_T_e is the electron temperature scale length), which is due to a strong shift between the density and temperature pedestal profiles associated with a closed divertor. The modeled turbulence drives significant heat transport with a lower pressure gradient that may broaden the pedestal to a greater degree than the empirical and theoretically predicted pedestal width scalings. Such a wide pedestal, coupled with a closed divertor, enables us to achieve a good core-edge scenario that integrates a high-temperature low-collisionality pedestal (pedestal top temperature T _e,ped > 0.8 keV and a pedestal top collisionality ν*_ped < 1) under detached divertor conditions. This paves a new path toward solving the core-edge integration issue in future fusion reactors.

Original language	English
Article number	084002
Journal	Nuclear Fusion
Volume	63
Issue number	8
DOIs	https://doi.org/10.1088/1741-4326/acdfe2
State	Published - Aug 2023

Funding

This work is supported by the U.S. Department of Energy under DE-FC02-04ER54698, DE-SC0018287, and DE-AC04-94AL85000. We would like to thank the DIII-D operational team for the support and effort put into the experimental work. Author HW would like to thank Richard Groebner and Pengjun Sun for useful discussions. DISCLAIMER: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Funders	Funder number
United States Government
U.S. Department of Energy	DE-SC0018287, DE-AC04-94AL85000, DE-FC02-04ER54698

Keywords

H-mode pedestal
tokamak
turbulence

UN SDGs

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

Access to Document

10.1088/1741-4326/acdfe2

Cite this

Wang, H. Q., Hong, R., Jian, X., Rhodes, T. L., Guo, H. Y., Leonard, A. W., Ma, X., Watkins, J. G., Ren, J., Grierson, B. A., Shafer, M. W., Scotti, F., Osborne, T. H., Thomas, D. M., & Yan, Z. (2023). Direct measurement of the electron turbulence-broadening edge transport barrier to facilitate core-edge integration in tokamak fusion plasmas. Nuclear Fusion, 63(8), Article 084002. https://doi.org/10.1088/1741-4326/acdfe2

@article{dbf9d9032a3a4fc78455ced25320290c,

title = "Direct measurement of the electron turbulence-broadening edge transport barrier to facilitate core-edge integration in tokamak fusion plasmas",

abstract = "The integration of a high-performance core and a dissipative divertor, or the so-called {\textquoteleft}core-edge integration,{\textquoteright} has been widely identified as a critical gap in the design of future fusion reactors. In this letter, we report, for the first time, direct experimental evidence of electron turbulence at the DIII-D H-mode pedestal that correlates with the broadening of the pedestal and thus facilitates core-edge integration. In agreement with gyrokinetic simulations, this electron turbulence is enhanced by high η e (η e = Ln /LTe, where Ln is the density scale length and LTe is the electron temperature scale length), which is due to a strong shift between the density and temperature pedestal profiles associated with a closed divertor. The modeled turbulence drives significant heat transport with a lower pressure gradient that may broaden the pedestal to a greater degree than the empirical and theoretically predicted pedestal width scalings. Such a wide pedestal, coupled with a closed divertor, enables us to achieve a good core-edge scenario that integrates a high-temperature low-collisionality pedestal (pedestal top temperature T e,ped > 0.8 keV and a pedestal top collisionality ν*ped < 1) under detached divertor conditions. This paves a new path toward solving the core-edge integration issue in future fusion reactors.",

keywords = "H-mode pedestal, tokamak, turbulence",

author = "Wang, {H. Q.} and R. Hong and X. Jian and Rhodes, {T. L.} and Guo, {H. Y.} and Leonard, {A. W.} and X. Ma and Watkins, {J. G.} and J. Ren and Grierson, {B. A.} and Shafer, {M. W.} and F. Scotti and Osborne, {T. H.} and Thomas, {D. M.} and Z. Yan",

note = "Publisher Copyright: {\textcopyright} 2023 The Author(s). Published on behalf of IAEA by IOP Publishing Ltd",

year = "2023",

month = aug,

doi = "10.1088/1741-4326/acdfe2",

language = "English",

volume = "63",

journal = "Nuclear Fusion",

issn = "0029-5515",

publisher = "IOP Publishing",

number = "8",

}

Wang, HQ, Hong, R, Jian, X, Rhodes, TL, Guo, HY, Leonard, AW, Ma, X, Watkins, JG, Ren, J, Grierson, BA, Shafer, MW, Scotti, F, Osborne, TH, Thomas, DM & Yan, Z 2023, 'Direct measurement of the electron turbulence-broadening edge transport barrier to facilitate core-edge integration in tokamak fusion plasmas', Nuclear Fusion, vol. 63, no. 8, 084002. https://doi.org/10.1088/1741-4326/acdfe2

TY - JOUR

T1 - Direct measurement of the electron turbulence-broadening edge transport barrier to facilitate core-edge integration in tokamak fusion plasmas

AU - Wang, H. Q.

AU - Hong, R.

AU - Jian, X.

AU - Rhodes, T. L.

AU - Guo, H. Y.

AU - Leonard, A. W.

AU - Ma, X.

AU - Watkins, J. G.

AU - Ren, J.

AU - Grierson, B. A.

AU - Shafer, M. W.

AU - Scotti, F.

AU - Osborne, T. H.

AU - Thomas, D. M.

AU - Yan, Z.

PY - 2023/8

Y1 - 2023/8

N2 - The integration of a high-performance core and a dissipative divertor, or the so-called ‘core-edge integration,’ has been widely identified as a critical gap in the design of future fusion reactors. In this letter, we report, for the first time, direct experimental evidence of electron turbulence at the DIII-D H-mode pedestal that correlates with the broadening of the pedestal and thus facilitates core-edge integration. In agreement with gyrokinetic simulations, this electron turbulence is enhanced by high η e (η e = Ln /LTe, where Ln is the density scale length and LTe is the electron temperature scale length), which is due to a strong shift between the density and temperature pedestal profiles associated with a closed divertor. The modeled turbulence drives significant heat transport with a lower pressure gradient that may broaden the pedestal to a greater degree than the empirical and theoretically predicted pedestal width scalings. Such a wide pedestal, coupled with a closed divertor, enables us to achieve a good core-edge scenario that integrates a high-temperature low-collisionality pedestal (pedestal top temperature T e,ped > 0.8 keV and a pedestal top collisionality ν*ped < 1) under detached divertor conditions. This paves a new path toward solving the core-edge integration issue in future fusion reactors.

AB - The integration of a high-performance core and a dissipative divertor, or the so-called ‘core-edge integration,’ has been widely identified as a critical gap in the design of future fusion reactors. In this letter, we report, for the first time, direct experimental evidence of electron turbulence at the DIII-D H-mode pedestal that correlates with the broadening of the pedestal and thus facilitates core-edge integration. In agreement with gyrokinetic simulations, this electron turbulence is enhanced by high η e (η e = Ln /LTe, where Ln is the density scale length and LTe is the electron temperature scale length), which is due to a strong shift between the density and temperature pedestal profiles associated with a closed divertor. The modeled turbulence drives significant heat transport with a lower pressure gradient that may broaden the pedestal to a greater degree than the empirical and theoretically predicted pedestal width scalings. Such a wide pedestal, coupled with a closed divertor, enables us to achieve a good core-edge scenario that integrates a high-temperature low-collisionality pedestal (pedestal top temperature T e,ped > 0.8 keV and a pedestal top collisionality ν*ped < 1) under detached divertor conditions. This paves a new path toward solving the core-edge integration issue in future fusion reactors.

KW - H-mode pedestal

KW - tokamak

KW - turbulence

UR - http://www.scopus.com/inward/record.url?scp=85165172309&partnerID=8YFLogxK

U2 - 10.1088/1741-4326/acdfe2

DO - 10.1088/1741-4326/acdfe2

M3 - Article

AN - SCOPUS:85165172309

SN - 0029-5515

VL - 63

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 8

M1 - 084002

ER -

Direct measurement of the electron turbulence-broadening edge transport barrier to facilitate core-edge integration in tokamak fusion plasmas

Abstract

Funding

Keywords

UN SDGs

Access to Document

Other files and links

Fingerprint

Cite this