Parameter space validation through OOPS simulations of plasma burnthrough and discharge evolution in the SST-1 tokamak

Plasma burnthrough and current ramp-up phases in an SST-1 superconducting tokamak are simulated by the OOPS code. The main purpose of this study is to optimize the operation regime in SST-1 through the input parameter scan for OOPS for both successful and failed shots from the SST-1 database. SST-1 is now equipped with carbon plasma facing components (PFCs). Hence, PFCs are expected to offer a carbon dominated impurity environment. An electrically continuous vacuum vessel and cryostat hinder sufficient loop voltage during start-up, thereby rendering electron cyclotron resonance heating (ECRH) pre-ionization an absolute requirement. OOPS simulation is optimized for the essential plasma initiation parameters like the seed electron density n_e = 3 × 10¹⁷/m³ and the initial neutral density n₀ = 1-4 × 10¹⁸/m³ (corresponding to a tailored pre-fill pressure) and for an error magnetic field B_err ≤ 20 G. The simulation shows that the ECRH pre-ionization threshold power required for the successful plasma start-up under low available loop voltage conditions is ≥180 kW.