Active real-time control of Alfvén eigenmodes by neutral beam and electron cyclotron heating in the DIII-D tokamak

Wenhui Hu; K. E.J. Olofsson; A. S. Welander; W. W. Heidbrink; M. A. Van Zeeland; M. E. Austin; C. S. Collins; D. A. Humphreys; E. Kolemen; Jiangang Li; Bingjia Xiao

doi:10.1088/1741-4326/aaddaf

Active real-time control of Alfvén eigenmodes by neutral beam and electron cyclotron heating in the DIII-D tokamak

Wenhui Hu, K. E.J. Olofsson, A. S. Welander, W. W. Heidbrink, M. A. Van Zeeland, M. E. Austin, C. S. Collins, D. A. Humphreys, E. Kolemen, Jiangang Li, Bingjia Xiao

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

11 Scopus citations

Abstract

A real-time Alfvén eigenmode (AE) controller is designed and implemented for the first time in DIII-D. The experimental test consists of two parts: (i) open-loop and feedback control using neutral beam power as an actuator and (ii) open-loop control using electron cyclotron heating (ECH) as an actuator. Part (i) demonstrates the feasibility of varying neutral beam power injected into plasma to control overall AE amplitude as well as the successful application of real-time electron cyclotron emission (ECE) as the process controller's AE amplitude sensor. The temporal evolution of AE amplitude at a specific radial location has also been controlled by selecting a subset of the radial ECE array. Part (ii) finds a complicated dependence of AE evolution on ECH power and more dedicated investigation is needed to explore the dynamical ECH-control model. Additionally, the ratio between TRANSP calculated neutron rate and measured neutron rate is found to correspond closely with AE amplitudes in discharges with feedback control, verifying that this ratio can be another sensor for the control system.

Original language	English
Article number	124001
Journal	Nuclear Fusion
Volume	58
Issue number	12
DOIs	https://doi.org/10.1088/1741-4326/aaddaf
State	Published - Sep 17 2018
Externally published	Yes

Funding

The authors would like to express gratitude to Dr. John Ferron for his support of neutral beam modulation algorithm. The authors are also very grateful to Mr. Ben Penaflor for preparing the real-time ECE digitizer for the experiments. The authors want to thank Mr. Alan Hyatt and Dr. Michael Walker for their kind help and advice during the experiments. The authors would like to thank Dr. Xiaodi Du for calculations of the expected AE resonances. This work was supported by General Atomics under US Department of Energy contract DE-FC02-04ER54698.

Funders	Funder number
General Atomics
US Department of Energy	DE-FC02-04ER54698

Keywords

Alfven eigenmode
ECE
ECRH
NBI
feedback control
real-time control

UN SDGs

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

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@article{7b3914fe57ba48ba95e45ad771a53e21,

title = "Active real-time control of Alfv{\'e}n eigenmodes by neutral beam and electron cyclotron heating in the DIII-D tokamak",

abstract = "A real-time Alfv{\'e}n eigenmode (AE) controller is designed and implemented for the first time in DIII-D. The experimental test consists of two parts: (i) open-loop and feedback control using neutral beam power as an actuator and (ii) open-loop control using electron cyclotron heating (ECH) as an actuator. Part (i) demonstrates the feasibility of varying neutral beam power injected into plasma to control overall AE amplitude as well as the successful application of real-time electron cyclotron emission (ECE) as the process controller's AE amplitude sensor. The temporal evolution of AE amplitude at a specific radial location has also been controlled by selecting a subset of the radial ECE array. Part (ii) finds a complicated dependence of AE evolution on ECH power and more dedicated investigation is needed to explore the dynamical ECH-control model. Additionally, the ratio between TRANSP calculated neutron rate and measured neutron rate is found to correspond closely with AE amplitudes in discharges with feedback control, verifying that this ratio can be another sensor for the control system.",

keywords = "Alfven eigenmode, ECE, ECRH, NBI, feedback control, real-time control",

author = "Wenhui Hu and Olofsson, {K. E.J.} and Welander, {A. S.} and Heidbrink, {W. W.} and {Van Zeeland}, {M. A.} and Austin, {M. E.} and Collins, {C. S.} and Humphreys, {D. A.} and E. Kolemen and Jiangang Li and Bingjia Xiao",

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

language = "English",

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T1 - Active real-time control of Alfvén eigenmodes by neutral beam and electron cyclotron heating in the DIII-D tokamak

AU - Hu, Wenhui

AU - Olofsson, K. E.J.

AU - Welander, A. S.

AU - Heidbrink, W. W.

AU - Van Zeeland, M. A.

AU - Austin, M. E.

AU - Collins, C. S.

AU - Humphreys, D. A.

AU - Kolemen, E.

AU - Li, Jiangang

AU - Xiao, Bingjia

PY - 2018/9/17

Y1 - 2018/9/17

N2 - A real-time Alfvén eigenmode (AE) controller is designed and implemented for the first time in DIII-D. The experimental test consists of two parts: (i) open-loop and feedback control using neutral beam power as an actuator and (ii) open-loop control using electron cyclotron heating (ECH) as an actuator. Part (i) demonstrates the feasibility of varying neutral beam power injected into plasma to control overall AE amplitude as well as the successful application of real-time electron cyclotron emission (ECE) as the process controller's AE amplitude sensor. The temporal evolution of AE amplitude at a specific radial location has also been controlled by selecting a subset of the radial ECE array. Part (ii) finds a complicated dependence of AE evolution on ECH power and more dedicated investigation is needed to explore the dynamical ECH-control model. Additionally, the ratio between TRANSP calculated neutron rate and measured neutron rate is found to correspond closely with AE amplitudes in discharges with feedback control, verifying that this ratio can be another sensor for the control system.

AB - A real-time Alfvén eigenmode (AE) controller is designed and implemented for the first time in DIII-D. The experimental test consists of two parts: (i) open-loop and feedback control using neutral beam power as an actuator and (ii) open-loop control using electron cyclotron heating (ECH) as an actuator. Part (i) demonstrates the feasibility of varying neutral beam power injected into plasma to control overall AE amplitude as well as the successful application of real-time electron cyclotron emission (ECE) as the process controller's AE amplitude sensor. The temporal evolution of AE amplitude at a specific radial location has also been controlled by selecting a subset of the radial ECE array. Part (ii) finds a complicated dependence of AE evolution on ECH power and more dedicated investigation is needed to explore the dynamical ECH-control model. Additionally, the ratio between TRANSP calculated neutron rate and measured neutron rate is found to correspond closely with AE amplitudes in discharges with feedback control, verifying that this ratio can be another sensor for the control system.

KW - Alfven eigenmode

KW - ECE

KW - ECRH

KW - NBI

KW - feedback control

KW - real-time control

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JO - Nuclear Fusion

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ER -

Active real-time control of Alfvén eigenmodes by neutral beam and electron cyclotron heating in the DIII-D tokamak

Abstract

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Keywords

UN SDGs

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