Q > 1 operation space in the first SPARC campaign

Q > 1 is predicted to be achieved on SPARC with L-mode confinement scaling assumptions, I_p ~ 8.5 MA, and B_T = 12.2T, producing more than 8 MW of D:T fusion power for at least two seconds. L-mode Q > 1 operation space exists at volume average densities in the range of 1 - 3 x 10²⁰ m^-3 (f_G = 0.12 - 0.36) where the lowest densities are near the expected LOC-SOC confinement transition. Probabilistic analysis of error field sources quantifies a < 1% chance that access to low density will be restricted by locked-modes. Reduced models of the ICRH heating provide fast estimates of the RF coupling and operation limit at low density. The core and boundary impurity species and concentrations are set by the requirements to radiate sufficient power to reach strike point temperatures, ~40 eV, that do not exceed prior empirical demonstrations while also maintaining Z_eff < 3 as required by the ohmic flux consumption rate and minimizing the dilution of the main ions. Elevating the L-mode confinement scaling expectation by 20% results in achieving Q > 1 over a wide operational window, while reducing it by 20% makes Q > 1 unlikely in L-mode. Recent L-mode energy and particle transport predictions for SPARC help quantify the likelihood of success for the Q > 1 mission with L-mode scenarios.