Tearing Growth Rates Combining Toroidal Stability Calculations With Two-Fluid Plasma Slab Model Resonant Layers

We have developed a new classical tearing mode (TM) stability simulation workflow that solves the resistive inner layer equations in a plasma slab to yield a linear, quasi-toroidal TM growth rate. Our workflow combines two-fluid and drift MHD effects in a slab approximation of the resistive inner layer (SLAYER) with an effective tearing stability index Δ_eff = Δ′ - Δ_crit. The STRIDE code is used to calculate a toroidal Δ′ that includes shaping effects, and our toroidal Δ_crit incorporates effects of thermal conduction on Glasser stabilization. This workflow is rapid and numerically robust across reactor-relevant plasma conditions, and yields growth rates that closely align with analytic predictions in well-documented linear growth rate regimes. Using model equilibria and propagating synthetic uncertainties from the pressure and toroidal current profiles, we analyzed TM stability across scans of plasma β, aspect ratio, elongation, and triangularity. Scans with and without consideration of rational surface coupling are compared. This capability to quickly and robustly predict classical tearing stability in tokamaks will facilitate the mapping of TM stable operational regimes and design of safe discharge trajectories in future devices.