Progress Towards a Predictive DIII-D Digital Twin with Neutral Beam Heat-Load and As-built Geometry

A selection of recent experiments at the DIII-D tokamak are digitally recreated in high-fidelity using as-built device data, demonstrating the impact on experimental decision making using a digital twin. The first is an investigation of a series of shots with neutral beam heating and excessively high carbon impurities, where a digital twin can avoid the use of experimental run time to determine which beam is likely creating the impurity source. The second is where heating inside a beam duct created a localized hot-spot that exceeded nominal limits. Presented here are concrete examples of how a digital twin can be used to improve operational efficiency and altogether avoid scenarios that present a high risk to the integrity of the device. To achieve this, a digital twin of DIII-D is being constructed by integrating the particle following code IonOrb with sub-millimeter accuracy laser scan data of the as-built first wall, and extending it beyond the toroidal field coils to include the ducts connecting the neutral beam injectors with the torus. Progress will be reported on the integration of a data-driven predictive equilibrium (using selective state-space models) to offer a prediction of neutral beam heat-load prior to the planned plasma discharge.