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

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. Here, 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.

Authors:
ORCiD logo [1]; ORCiD logo [2];  [2]; ORCiD logo [3];  [2];  [4];  [2];  [2];  [5];  [6];  [7]
  1. Chinese Academy of Sciences, Anhui (People's Republic of China); Univ. of Science and Technology of China, Anhui (People's Republic of China)
  2. General Atomics, San Diego, CA (United States)
  3. Univ. of California, Irvine, CA (United States)
  4. Univ. of Texas-Austin, Austin, TX (United States)
  5. Princeton Univ., Princeton, NJ (United States)
  6. Chinese Academy of Sciences, Anhui (People's Republic of China)
  7. Chinese Academy of Science, Anhui (People's Republic of China)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE
Contributing Org.:
DIII-D Team
OSTI Identifier:
1566855
Grant/Contract Number:  
FC02-04ER54698
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 58; 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; Alfven eigenmode; feedback control; real-time control; ECRH; NBI; ECE

Citation Formats

Hu, Wenhui, Olofsson, K. E. J., Welander, A. S., Heidbrink, W. W., Van Zeeland, M. A., Austin, M. E., Collins, C. S., Humphreys, D. A., Kolemen, E., Li, Jiangang, and Xiao, Bingjia. Active real-time control of Alfvén eigenmodes by neutral beam and electron cyclotron heating in the DIII-D tokamak. United States: N. p., 2018. Web. doi:10.1088/1741-4326/aaddaf.
Hu, Wenhui, Olofsson, K. E. J., Welander, A. S., Heidbrink, W. W., Van Zeeland, M. A., Austin, M. E., Collins, C. S., Humphreys, D. A., Kolemen, E., Li, Jiangang, & Xiao, Bingjia. Active real-time control of Alfvén eigenmodes by neutral beam and electron cyclotron heating in the DIII-D tokamak. United States. doi:10.1088/1741-4326/aaddaf.
Hu, Wenhui, Olofsson, K. E. J., Welander, A. S., Heidbrink, W. W., Van Zeeland, M. A., Austin, M. E., Collins, C. S., Humphreys, D. A., Kolemen, E., Li, Jiangang, and Xiao, Bingjia. Mon . "Active real-time control of Alfvén eigenmodes by neutral beam and electron cyclotron heating in the DIII-D tokamak". United States. doi:10.1088/1741-4326/aaddaf. https://www.osti.gov/servlets/purl/1566855.
@article{osti_1566855,
title = {Active real-time control of Alfvén eigenmodes by neutral beam and electron cyclotron heating in the DIII-D tokamak},
author = {Hu, Wenhui 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 Kolemen, E. and Li, Jiangang and Xiao, Bingjia},
abstractNote = {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. Here, 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.},
doi = {10.1088/1741-4326/aaddaf},
journal = {Nuclear Fusion},
number = 12,
volume = 58,
place = {United States},
year = {2018},
month = {9}
}

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