Design and implementation of the digital twin system for the negative ion based neutral beam injection

To facilitate experimental management, feedback, and provide a platform for artificial intelligence (AI) model, a digital twin (DT) system has been developed for the negative ion based neutral beam injection (NNBI) at the comprehensive research facility for fusion technology (CRAFT). This system is capable of simulating experimental operations in a virtual space, mapping the operational status of the radio frequency based negative ion source (RF-NIS) of NNBI, and providing real-time feedback on experimental outcomes. This paper details the design and implementation of the CRAFT NNBI DT system. On the physical side, the system replicates complex entity system and simulates the actual workflow of the NNBI. On the DT side, it involves the dynamic state mapping of NNBI entity and the interaction exchange of real and virtual data. The system enables enhanced control over NNBI operations and experimental feedback, thereby supporting the implementation of future kilosecond long-pulse experiments.