Real time plasma facing component modeling and responses in the SPARC plasma control system.*

The combination of high field (BT = 12.2T) and high plasma current (Ip = 8.7 MA) may lead to narrow a heat flux width on SPARC, resulting in unmitigated values of q_|| on the order of 10 GW/m². The SPARC plasma control system (PCS) will actively manage the heat load on PFCs to keep them below engineering limits using strikepoint sweeping, divertor gas injection and early pulse termination. To enable this functionality, a deterministic, real time, and toroidally symmetric heat flux and temperature model inspired by the HEAT and WALLS/VTM codes has been developed. The model includes optical particle flux heating with shadowing, photon loading, and volumetric neutron heating. These feed 1D heat equations with temperature dependent material properties; all running over 100 Hz at a mean poloidal resolution of ~0.5 mm. The forward model outputs are combined with thermocouple measurements and monitored via an off normal warning (ONW) system. The PCS can make use of ONW to modify the pulse trajectory and avoid already heated regions. Examples of PCS temperature reconstructions and pulse trajectory modifications run against the in-house real-time capable  simulator (COMET) will be presented. Real-time calculations show good agreement with higher-fidelity HEAT results.