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Title: Strike Point Control for the National Spherical Torus Experiment (NSTX)

Abstract

This paper presents the first control algorithm for the inner and outer strike point position for a Spherical Torus (ST) fusion experiment and the performance analysis of the controller. A liquid lithium divertor (LLD) will be installed on NSTX which is believed to provide better pumping than lithium coatings on carbon PFCs. The shape of the plasma dictates the pumping rate of the lithium by channeling the plasma to LLD, where strike point location is the most important shape parameter. Simulations show that the density reduction depends on the proximity of strike point to LLD. Experiments were performed to study the dynamics of the strike point, design a new controller to change the location of the strike point to desired location and stabilize it. The most effective PF coils in changing inner and outer strike points were identified using equilibrium code. The PF coil inputs were changed in a step fashion between various set points and the step response of the strike point position was obtained. From the analysis of the step responses, PID controllers for the strike points were obtained and the controller was tuned experimentally for better performance. The strike controller was extended to include the outer-strike pointmore » on the inner plate to accommodate the desired low outer-strike points for the experiment with the aim of achieving "snowflake" divertor configuration in NSTX.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
984350
Report Number(s):
PPPL-4533
TRN: US1006432
DOE Contract Number:  
DE-ACO2-09CH11466
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ALGORITHMS; CARBON; CHANNELING; COATINGS; CONFIGURATION; DESIGN; DIVERTORS; LITHIUM; PERFORMANCE; PLASMA; PLATES; PUMPING; SHAPE; Divertors, Automatic Control, Magnetic Fields

Citation Formats

Kolemen, E., Gates, D. A., Rowley, C. W., Kasdin, N. J., Kallman, J., Gerhardt, S., Soukhanovskii, V., and Mueller, D. Strike Point Control for the National Spherical Torus Experiment (NSTX). United States: N. p., 2010. Web. doi:10.2172/984350.
Kolemen, E., Gates, D. A., Rowley, C. W., Kasdin, N. J., Kallman, J., Gerhardt, S., Soukhanovskii, V., & Mueller, D. Strike Point Control for the National Spherical Torus Experiment (NSTX). United States. https://doi.org/10.2172/984350
Kolemen, E., Gates, D. A., Rowley, C. W., Kasdin, N. J., Kallman, J., Gerhardt, S., Soukhanovskii, V., and Mueller, D. 2010. "Strike Point Control for the National Spherical Torus Experiment (NSTX)". United States. https://doi.org/10.2172/984350. https://www.osti.gov/servlets/purl/984350.
@article{osti_984350,
title = {Strike Point Control for the National Spherical Torus Experiment (NSTX)},
author = {Kolemen, E. and Gates, D. A. and Rowley, C. W. and Kasdin, N. J. and Kallman, J. and Gerhardt, S. and Soukhanovskii, V. and Mueller, D.},
abstractNote = {This paper presents the first control algorithm for the inner and outer strike point position for a Spherical Torus (ST) fusion experiment and the performance analysis of the controller. A liquid lithium divertor (LLD) will be installed on NSTX which is believed to provide better pumping than lithium coatings on carbon PFCs. The shape of the plasma dictates the pumping rate of the lithium by channeling the plasma to LLD, where strike point location is the most important shape parameter. Simulations show that the density reduction depends on the proximity of strike point to LLD. Experiments were performed to study the dynamics of the strike point, design a new controller to change the location of the strike point to desired location and stabilize it. The most effective PF coils in changing inner and outer strike points were identified using equilibrium code. The PF coil inputs were changed in a step fashion between various set points and the step response of the strike point position was obtained. From the analysis of the step responses, PID controllers for the strike points were obtained and the controller was tuned experimentally for better performance. The strike controller was extended to include the outer-strike point on the inner plate to accommodate the desired low outer-strike points for the experiment with the aim of achieving "snowflake" divertor configuration in NSTX.},
doi = {10.2172/984350},
url = {https://www.osti.gov/biblio/984350}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jul 09 00:00:00 EDT 2010},
month = {Fri Jul 09 00:00:00 EDT 2010}
}