Mode rotation control in a tokamak with a feedback-driven biased electrode
Abstract
Rotation of the plasma and MHD modes in tokamaks has been shown to stabilize resistive wall and tearing modes as well as improve confinement through suppression of edge turbulence. In this work, we control mode rotation with a biased electrode inserted into the plasma of the High Beta Tokamak-Extended Pulse’s facility in conjunction with its active GPU (Graphical Processing Unit) feedback system. We first characterize a negative linear relationship between the electrode voltage and mode rotation. Using this relationship, we design, simulate, and implement a proof-of-concept, GPU-based active-control system, which shows consistent success in controlling mode rotation in both feedforward and feedback operation. Controllability is limited by operating conditions, the electrode’s voltage range, and by the electrode’s proximity to the vessel’s walls. The final control system has a 15 μs cycle time, but the addition of various signal filters results in a full cycle latency of 200 μs.
- Authors:
-
[1];
[1];
[2];
[1];
[1];
[1]
- Columbia Univ., New York, NY (United States)
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
- Publication Date:
- Research Org.:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- OSTI Identifier:
- 1512695
- Grant/Contract Number:
- FG02-86ER53222; SC0014664
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Review of Scientific Instruments
- Additional Journal Information:
- Journal Volume: 90; Journal Issue: 2; Journal ID: ISSN 0034-6748
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Citation Formats
Brooks, J. W., Stewart, I. G., Boyer, M. D., Levesque, J. P., Mauel, M. E., and Navratil, G. A. Mode rotation control in a tokamak with a feedback-driven biased electrode. United States: N. p., 2019.
Web. doi:10.1063/1.5062271.
Brooks, J. W., Stewart, I. G., Boyer, M. D., Levesque, J. P., Mauel, M. E., & Navratil, G. A. Mode rotation control in a tokamak with a feedback-driven biased electrode. United States. https://doi.org/10.1063/1.5062271
Brooks, J. W., Stewart, I. G., Boyer, M. D., Levesque, J. P., Mauel, M. E., and Navratil, G. A. Fri .
"Mode rotation control in a tokamak with a feedback-driven biased electrode". United States. https://doi.org/10.1063/1.5062271. https://www.osti.gov/servlets/purl/1512695.
@article{osti_1512695,
title = {Mode rotation control in a tokamak with a feedback-driven biased electrode},
author = {Brooks, J. W. and Stewart, I. G. and Boyer, M. D. and Levesque, J. P. and Mauel, M. E. and Navratil, G. A.},
abstractNote = {Rotation of the plasma and MHD modes in tokamaks has been shown to stabilize resistive wall and tearing modes as well as improve confinement through suppression of edge turbulence. In this work, we control mode rotation with a biased electrode inserted into the plasma of the High Beta Tokamak-Extended Pulse’s facility in conjunction with its active GPU (Graphical Processing Unit) feedback system. We first characterize a negative linear relationship between the electrode voltage and mode rotation. Using this relationship, we design, simulate, and implement a proof-of-concept, GPU-based active-control system, which shows consistent success in controlling mode rotation in both feedforward and feedback operation. Controllability is limited by operating conditions, the electrode’s voltage range, and by the electrode’s proximity to the vessel’s walls. The final control system has a 15 μs cycle time, but the addition of various signal filters results in a full cycle latency of 200 μs.},
doi = {10.1063/1.5062271},
journal = {Review of Scientific Instruments},
number = 2,
volume = 90,
place = {United States},
year = {Fri Feb 22 00:00:00 EST 2019},
month = {Fri Feb 22 00:00:00 EST 2019}
}
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