Offline Reinforcement Learning for Rotation Profile Control in Tokamaks

Fuente: arXiv
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Autori principali: Sonker, Rohit, Kaga, Hiro Josep Farre, Chen, Jiayu, Rothstein, Andrew, Char, Ian, Shousha, Ricardo, Kolemen, Egemen, Schneider, Jeff
Natura: Preprint
Pubblicazione: 2026
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author Sonker, Rohit
Kaga, Hiro Josep Farre
Chen, Jiayu
Rothstein, Andrew
Char, Ian
Shousha, Ricardo
Kolemen, Egemen
Schneider, Jeff
author_facet Sonker, Rohit
Kaga, Hiro Josep Farre
Chen, Jiayu
Rothstein, Andrew
Char, Ian
Shousha, Ricardo
Kolemen, Egemen
Schneider, Jeff
contents Tokamaks remain leading candidates for achieving practical fusion energy, yet many important control problems inside these devices are still difficult or unsolved. One such challenge is controlling the plasma rotation profile, which strongly influences stability, confinement, and transport. While the average rotation can be controlled, controlling the full profile is challenging due to high dimensionality, response to multiple actuators and dependence on plasma condition. Learning-based control methods, such as reinforcement learning (RL), provide a potential solution to this challenging problem with ability to model complex interactions leading to effective multi-input multi-output control. However, learning such policies is challenging due to the lack of accurate simulators that can model the rotation profile dynamics. In this work, we investigate the use of offline RL and offline model-based RL algorithms for rotation profile control, training them solely on historical data from the DIII-D tokamak. Our final method uses probabilistic models of plasma dynamics to generate rollouts for RL training. We deploy this policy on the DIII-D Tokamak and observe promising real-world results. We conclude by highlighting key challenges and insights from training and deploying an RL policy on a complex physical device while using only limited past data.
format Preprint
id arxiv_https___arxiv_org_abs_2605_05857
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Offline Reinforcement Learning for Rotation Profile Control in Tokamaks
Sonker, Rohit
Kaga, Hiro Josep Farre
Chen, Jiayu
Rothstein, Andrew
Char, Ian
Shousha, Ricardo
Kolemen, Egemen
Schneider, Jeff
Machine Learning
Tokamaks remain leading candidates for achieving practical fusion energy, yet many important control problems inside these devices are still difficult or unsolved. One such challenge is controlling the plasma rotation profile, which strongly influences stability, confinement, and transport. While the average rotation can be controlled, controlling the full profile is challenging due to high dimensionality, response to multiple actuators and dependence on plasma condition. Learning-based control methods, such as reinforcement learning (RL), provide a potential solution to this challenging problem with ability to model complex interactions leading to effective multi-input multi-output control. However, learning such policies is challenging due to the lack of accurate simulators that can model the rotation profile dynamics. In this work, we investigate the use of offline RL and offline model-based RL algorithms for rotation profile control, training them solely on historical data from the DIII-D tokamak. Our final method uses probabilistic models of plasma dynamics to generate rollouts for RL training. We deploy this policy on the DIII-D Tokamak and observe promising real-world results. We conclude by highlighting key challenges and insights from training and deploying an RL policy on a complex physical device while using only limited past data.
title Offline Reinforcement Learning for Rotation Profile Control in Tokamaks
topic Machine Learning
url https://arxiv.org/abs/2605.05857