Modeling of SPARC Cold and Hot Vertical Displacement Events with M3D-C1*

Vertical displacement events (VDEs) pose major challenges in tokamak operations and design. In SPARC, despite substantial efforts on disruption prediction, avoidance, and mitigation, unmitigated disruptions and VDEs are expected [Sweeney JPP2020]. Therefore, appropriate modeling is critical to better assess their consequences. M3D-C1 [Jardin CSD2012], a 3D nonlinear MHD code, has become an important high-fidelity modeling tool to help inform SPARC design and operation as well as to provide guidance for ARC design. As part of the effort in building confidence in the modeling, we conducted a validation exercise with Alcator C-Mod VDE data. Then, we employed M3D-C1 to simulate 2D hot and cold VDEs on the SPARC primary reference discharge to assess electromagnetic loads and to determine the critical current that can trigger vertical displacement when the current quench time scale is much shorter than the vessel L/R time. We performed scans over different parameters of interest, included halo currents, and found that the amount of halo currents has a stabilizing role on the plasma vertical displacement. Similar studies are presently being conducted on ARC that will help faster-turnaround codes to estimate ARC EM loads during the design phase.