First application of data assimilation-based control to fusion plasma
Yuya Morishita, S. Murakami, N. Kenmochi, H. Funaba, I. Yamada, Yoshinori Mizuno, Kazuki Nagahara, H. Nuga, R. Seki, M. Yokoyama, G. Ueno, M. Osakabe
Abstract
Magnetic fusion plasmas, which are complex systems comprising numerous interacting elements, have large uncertainties. Therefore, future fusion reactors require prediction-based advanced control systems with an adaptive system model and control estimation robust to uncertainties in the model and observations. To address this challenge, we introduced a control approach based on data assimilation (DA), which describes the system model adaptation and control estimation based on the state probability distribution. The first implementation of a DA-based control system was achieved at the Large Helical Device to control the high temperature plasma. The experimental results indicate that the control system enhanced the predictive capability using real-time observations and adjusted the electron cyclotron heating power for a target temperature. The DA-based control system provides a flexible platform for advanced control in future fusion reactors.