Characterization and performance predictions of L-mode plasmas in the SPARC tokamak

We present a methodology for consistently, reliably, and quickly predicting the performance of L-mode plasmas using high-fidelity transport models. We build on the GACODE suite of tools, in particular TGYRO, TGLF and NEO, and sweep both boundary conditions as well as plasma input parameters in search of optimal steady-state solutions which are in-line with empirical scaling laws. This is motivated by the lack of reliable models for the boundary condition, unlike the pedestal models that exist for H-mode. We also recommend several configurations of practical relevance to achieving consistent convergence. We evaluate our methods on the SPARC tokamak to assess the possibility of accessing breakeven and Q>2 in L-mode scenarios.