Implementation of a runaway electron module in HEAT

Runaway electrons occur in tokamak devices when the stopping power from collisions is no longer sufficient to stop electron acceleration due to electric fields. These relativistic electrons can carry tens of MJ of energy and cause damage to plasma facing components (PFCs) if unmitigated. Assessing that damage and its consequences is critical for tokamak operations and the lifetime of machines. HEAT is a code that combines plasma physics and engineering CAD to assess heat fluxes and their effects on PFCs. A new runaway electron module has been added to HEAT to assess the damage caused by runaway electron impacts. This module takes an input runaway electron distribution function and calculates the time varying trajectories of runaways within the tokamak. The intersections of these trajectories with PFCs and analytical stopping power formulas are used to determine the volumetric energy deposition of the runaway electrons. This is then used to calculate temperatures and phase changes in the PFCs. Simulations using this module will be shown for SPARC and Alcator C-Mod.