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Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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Conference on Nuclear Training and Education: A Biennial International Forum (CONTE 2025)
February 3–6, 2025
Amelia Island, FL|Omni Amelia Island Resort
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Fusion Science and Technology
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Christmas Night
Twas the night before Christmas when all through the houseNo electrons were flowing through even my mouse.
All devices were plugged in by the chimney with careWith the hope that St. Nikola Tesla would share.
Yong-Su Na, A. C. C. Sips, W. Treutterer, ASDEX Upgrade Team
Fusion Science and Technology | Volume 50 | Number 4 | November 2006 | Pages 490-502
Technical Paper | doi.org/10.13182/FST06-A1272
Articles are hosted by Taylor and Francis Online.
Control of the shape of the current density profile is essential to improve the confinement and the stability in the plasma, particularly for advanced tokamak scenarios with internal transport barriers. For real-time control of the current density profile, it is necessary to identify a model that describes the time evolution of the current density profile when additional current is driven by external current drive tools. This paper focuses on the identification of such models in ASDEX Upgrade. Neutral beam injection is planned as a tool to control the current density profile in ASDEX Upgrade. The possibility of modifying the current density profile using neutral beam injection is investigated by the ASTRA code simulations using the Weiland transport model. It is difficult to derive a physics-based model for the current profile modification with neutral beam injection because it is nonlinear and multivariable. Therefore, a numerical model, a state-space model suited for systems with many input and output signals, is employed for the modeling. The matrices of the state-space model are estimated using a database by a standard prediction error method that minimizes the difference between the model output and the reference output. The database consists of a set of perturbed input signals and simulated output signals. The input signals are the variations of neutral beam power from different beam sources, and the output signals are the variations of the total plasma pressure and the current density profile. The ASTRA code with the Weiland transport model is used for the simulations to create the database since experimental data are currently not available at ASDEX Upgrade. A test of identified models is carried out using another database, also produced by ASTRA, applying a step response pattern to the input signals. It is found that the models obtained predict the output of this database with high accuracies. It is possible to apply the approach developed here to other actuators in a similar way for the current profile control in existing and future experiments.
