Dependence of intrinsic torque and momentum confinement on normalized gyroradius and collisionality in the DIII-D tokamak

C. Chrystal; B. Grierson; W. Solomon; Tuomas Tala; J. deGrassie; C. Petty; Antti Salmi; K. Burrell

doi:10.1063/1.4978563

Dependence of intrinsic torque and momentum confinement on normalized gyroradius and collisionality in the DIII-D tokamak

C. Chrystal
, B. Grierson
, W. Solomon
, Tuomas Tala
, J. deGrassie
, C. Petty
, Antti Salmi
, K. Burrell

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

21 Citations (Scopus)

Abstract

The dependence of intrinsic torque and momentum confinement time on normalized gyroradius ( ρ_*) and collisionality ( ν_*) has been measured in the DIII-D tokamak. The intrinsic torque normalized to temperature is found to have ρ_* and ν_* dependencies of ρ_*^−1.5±0.8 and ν_*^0.26±0.04. This dependence on ρ_* is unexpectedly favorable (increasing as ρ_* decreases). The choice of normalization is important, and the implications are discussed. The unexpected dependence on ρ_* is found to be robust, despite some uncertainty in the choice of normalization. The dependence of momentum confinement on ρ_* does not clearly demonstrate Bohm or gyro-Bohm like scaling, and a weaker dependence on ν_* is found. The calculations required to use these dependencies to determine the intrinsic torque in future tokamaks such as ITER are presented, and the importance of the normalization is explained. Based on the currently available information, the intrinsic torque predicted for ITER is 33 N m, comparable to the expected torque available from neutral beam injection. The expected average intrinsic rotation associated with this intrinsic torque is small compared to current tokamaks, but it may still aid stability and performance in ITER.

Original language	English
Article number	042501
Journal	Physics of Plasmas
Volume	24
Issue number	4
DOIs	https://doi.org/10.1063/1.4978563
Publication status	Published - 2017
MoE publication type	A1 Journal article-refereed

Funding

This material is based on the work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Award Nos. DE-FC02-04ER54698 and DE-AC02-09CH11466. This work was carried out within the framework of the EUROfusion Consortium and received funding from the Euratom research and training programme 2014-2018 under Grant Agreement No. 633053. A portion of this work was conducted under the auspices of the ITPA Transport and Confinement Topical Group.

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10.1063/1.4978563

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@article{dc377096183f4540ab08016b02d83e75,

title = "Dependence of intrinsic torque and momentum confinement on normalized gyroradius and collisionality in the DIII-D tokamak",

abstract = "The dependence of intrinsic torque and momentum confinement time on normalized gyroradius ( ρ*) and collisionality ( ν*) has been measured in the DIII-D tokamak. The intrinsic torque normalized to temperature is found to have ρ* and ν* dependencies of ρ*−1.5±0.8 and ν*0.26±0.04. This dependence on ρ* is unexpectedly favorable (increasing as ρ* decreases). The choice of normalization is important, and the implications are discussed. The unexpected dependence on ρ* is found to be robust, despite some uncertainty in the choice of normalization. The dependence of momentum confinement on ρ* does not clearly demonstrate Bohm or gyro-Bohm like scaling, and a weaker dependence on ν* is found. The calculations required to use these dependencies to determine the intrinsic torque in future tokamaks such as ITER are presented, and the importance of the normalization is explained. Based on the currently available information, the intrinsic torque predicted for ITER is 33 N m, comparable to the expected torque available from neutral beam injection. The expected average intrinsic rotation associated with this intrinsic torque is small compared to current tokamaks, but it may still aid stability and performance in ITER.",

author = "C. Chrystal and B. Grierson and W. Solomon and Tuomas Tala and J. deGrassie and C. Petty and Antti Salmi and K. Burrell",

note = "The first author would like to thank R. Waltz for useful discussions on residual stress. DIII-D data shown in this paper can be obtained in digital format at the following link https://fusion.gat.com/global/D3D\_DMP.",

year = "2017",

doi = "10.1063/1.4978563",

language = "English",

volume = "24",

journal = "Physics of Plasmas",

issn = "1070-664X",

publisher = "American Institute of Physics (AIP)",

number = "4",

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TY - JOUR

T1 - Dependence of intrinsic torque and momentum confinement on normalized gyroradius and collisionality in the DIII-D tokamak

AU - Chrystal, C.

AU - Grierson, B.

AU - Solomon, W.

AU - Tala, Tuomas

AU - deGrassie, J.

AU - Petty, C.

AU - Salmi, Antti

AU - Burrell, K.

N1 - The first author would like to thank R. Waltz for useful discussions on residual stress. DIII-D data shown in this paper can be obtained in digital format at the following link https://fusion.gat.com/global/D3D_DMP.

PY - 2017

Y1 - 2017

N2 - The dependence of intrinsic torque and momentum confinement time on normalized gyroradius ( ρ*) and collisionality ( ν*) has been measured in the DIII-D tokamak. The intrinsic torque normalized to temperature is found to have ρ* and ν* dependencies of ρ*−1.5±0.8 and ν*0.26±0.04. This dependence on ρ* is unexpectedly favorable (increasing as ρ* decreases). The choice of normalization is important, and the implications are discussed. The unexpected dependence on ρ* is found to be robust, despite some uncertainty in the choice of normalization. The dependence of momentum confinement on ρ* does not clearly demonstrate Bohm or gyro-Bohm like scaling, and a weaker dependence on ν* is found. The calculations required to use these dependencies to determine the intrinsic torque in future tokamaks such as ITER are presented, and the importance of the normalization is explained. Based on the currently available information, the intrinsic torque predicted for ITER is 33 N m, comparable to the expected torque available from neutral beam injection. The expected average intrinsic rotation associated with this intrinsic torque is small compared to current tokamaks, but it may still aid stability and performance in ITER.

AB - The dependence of intrinsic torque and momentum confinement time on normalized gyroradius ( ρ*) and collisionality ( ν*) has been measured in the DIII-D tokamak. The intrinsic torque normalized to temperature is found to have ρ* and ν* dependencies of ρ*−1.5±0.8 and ν*0.26±0.04. This dependence on ρ* is unexpectedly favorable (increasing as ρ* decreases). The choice of normalization is important, and the implications are discussed. The unexpected dependence on ρ* is found to be robust, despite some uncertainty in the choice of normalization. The dependence of momentum confinement on ρ* does not clearly demonstrate Bohm or gyro-Bohm like scaling, and a weaker dependence on ν* is found. The calculations required to use these dependencies to determine the intrinsic torque in future tokamaks such as ITER are presented, and the importance of the normalization is explained. Based on the currently available information, the intrinsic torque predicted for ITER is 33 N m, comparable to the expected torque available from neutral beam injection. The expected average intrinsic rotation associated with this intrinsic torque is small compared to current tokamaks, but it may still aid stability and performance in ITER.

UR - https://www.scopus.com/pages/publications/85016420882

U2 - 10.1063/1.4978563

DO - 10.1063/1.4978563

M3 - Article

SN - 1070-664X

VL - 24

JO - Physics of Plasmas

JF - Physics of Plasmas

IS - 4

M1 - 042501

ER -

Dependence of intrinsic torque and momentum confinement on normalized gyroradius and collisionality in the DIII-D tokamak

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