A simple formulation of heat flux factor for transient heat loads

The heat flux factor is used to characterize pulsed heat loads in high heat flux experiments on plasma-facing materials. a material-dependent quantity called the critical heat flux factor FHFC is introduced. It is the heat flux factor required for the surface temperature to reach a critical temperature. Based on the analytical solution of transient heat conduction in a semi-infinite solid, an analytical expression between FHFC, thermophysical properties, and temperature difference is derived. The formulation is intended as a simplified screening metric for the preliminary comparison of candidate plasma-facing materials, rather than as a substitute for detailed nonlinear thermal analysis. The results show material comparisons across the periodic table and temperature – heat-flux-factor maps illustrating characteristic material limits under transient heat loads.