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Title: TRANSP-based optimization towards tokamak scenario development

Abstract

An optimization approach that incorporates the predictive transport code TRANSP is proposed for tokamak scenario development. Optimization methods are often employed to develop open-loop control strategies to aid access to high performance tokamak scenarios. Generally, the optimization approaches use control-oriented models, i.e. models that are reduced in complexity and prediction accuracy as compared to physics-oriented transport codes such as TRANSP. In the presented approach, an optimization procedure using the TRANSP code to simulate the tokamak plasma is considered for improved predictive capabilities. As a test case, the neutral beam injection (NBI) power is optimized to develop a control strategy that maximizes the noninductive current fraction during the ramp-up phase for NSTX-U. Simulation studies towards the achievement of noninductive ramp-up in NSTX-U have already been carried out with the TRANSP code. The optimization-based approach presented in this work is used to maximize the noninductive current fraction during ramp-up in NSTX-U, demonstrating that the scenario development task can be automated. An additional test case considers optimization of the current ramp rate in DIII-D for obtaining a stationary plasma characterized by a flat loop voltage profile in the flattop phase.

Authors:
 [1];  [1];  [2];  [2]
  1. Lehigh Univ., Bethlehem, PA (United States)
  2. Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Lehigh Univ., Bethlehem, PA (United States); General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1508622
Grant/Contract Number:  
SC0010661; FC02-04ER54698
Resource Type:
Accepted Manuscript
Journal Name:
Fusion Engineering and Design
Additional Journal Information:
Journal Name: Fusion Engineering and Design; Journal ID: ISSN 0920-3796
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; TRANSP; Scenario development; Optimal control design; Optimal plasma scenario planning; NSTX-UDIII-D

Citation Formats

Wehner, W. P., Schuster, E., Boyer, M. D., and Poli, F. M. TRANSP-based optimization towards tokamak scenario development. United States: N. p., 2019. Web. doi:10.1016/j.fusengdes.2019.01.019.
Wehner, W. P., Schuster, E., Boyer, M. D., & Poli, F. M. TRANSP-based optimization towards tokamak scenario development. United States. doi:10.1016/j.fusengdes.2019.01.019.
Wehner, W. P., Schuster, E., Boyer, M. D., and Poli, F. M. Tue . "TRANSP-based optimization towards tokamak scenario development". United States. doi:10.1016/j.fusengdes.2019.01.019.
@article{osti_1508622,
title = {TRANSP-based optimization towards tokamak scenario development},
author = {Wehner, W. P. and Schuster, E. and Boyer, M. D. and Poli, F. M.},
abstractNote = {An optimization approach that incorporates the predictive transport code TRANSP is proposed for tokamak scenario development. Optimization methods are often employed to develop open-loop control strategies to aid access to high performance tokamak scenarios. Generally, the optimization approaches use control-oriented models, i.e. models that are reduced in complexity and prediction accuracy as compared to physics-oriented transport codes such as TRANSP. In the presented approach, an optimization procedure using the TRANSP code to simulate the tokamak plasma is considered for improved predictive capabilities. As a test case, the neutral beam injection (NBI) power is optimized to develop a control strategy that maximizes the noninductive current fraction during the ramp-up phase for NSTX-U. Simulation studies towards the achievement of noninductive ramp-up in NSTX-U have already been carried out with the TRANSP code. The optimization-based approach presented in this work is used to maximize the noninductive current fraction during ramp-up in NSTX-U, demonstrating that the scenario development task can be automated. An additional test case considers optimization of the current ramp rate in DIII-D for obtaining a stationary plasma characterized by a flat loop voltage profile in the flattop phase.},
doi = {10.1016/j.fusengdes.2019.01.019},
journal = {Fusion Engineering and Design},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {3}
}

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This content will become publicly available on March 5, 2020
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