Investigation of Closed Loop Control in Tokamaks Leveraging Disruption Event Characterization and Forecasting (DECAF)*

Ensuring the avoidance of disruptions in tokamak operations is critical for achieving sustainable fusion energy production. This study aims to enhance control mechanisms using Disruption Event Characterization and Forecasting (DECAF) [1] real-time physics modules, thereby supporting continuous high-performance operation. DECAF provides a framework for predicting and analyzing disruption chain events in tokamaks that can offer guidance for disruption avoidance actuators. A real-time DECAF module has forecast locked tearing mode instabilities with 100% accuracy in dedicated experiments [2,3], providing early warnings that afford sufficient time to guide actuators in the KSTAR plasma control system to attempt disruption avoidance. We additionally investigate the correlations between electron temperature crashes and locked tearing modes to develop a control system using multiple DECAF modules as sensors, and electron cyclotron heating, neutral beam heating, and 3D field as actuators for KSTAR. Implications for multiple devices are analyzed to extrapolate findings and to more generally examine the performance of the advanced control system.

[1] S.A. Sabbagh, et al., Phys. Plasmas 30, 032506 (2023); https://doi.org/10.1063/5.0133825

[2] S.A. Sabbagh, et al., IAEA Fusion Energy Conference 2023 (IAEA-CN-316-2038)

[3] W.H. Ko, et al., IAEA Fusion Energy Conference 2023 (IAEA-CN-316-1855).