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The SPARC tokamak is a critical next step towards commercial fusion energy. SPARC is designed as a high-field (
$B_0 = 12.2$ T), compact (
$R_0 = 1.85$ m, 
$a = 0.57$ m), superconducting, D-T tokamak with the goal of producing fusion gain 
$Q>2$ from a magnetically confined fusion plasma for the first time. Currently under design, SPARC will continue the high-field path of the Alcator series of tokamaks, utilizing new magnets based on rare earth barium copper oxide high-temperature superconductors to achieve high performance in a compact device. The goal of 
$Q>2$ is achievable with conservative physics assumptions (
$H_{98,y2} = 0.7$) and, with the nominal assumption of 
$H_{98,y2} = 1$, SPARC is projected to attain 
$Q \approx 11$ and 
$P_{\textrm {fusion}} \approx 140$ MW. SPARC will therefore constitute a unique platform for burning plasma physics research with high density (
$\langle n_{e} \rangle \approx 3 \times 10^{20}\ \textrm {m}^{-3}$), high temperature (
$\langle T_e \rangle \approx 7$ keV) and high power density (
$P_{\textrm {fusion}}/V_{\textrm {plasma}} \approx 7\ \textrm {MW}\,\textrm {m}^{-3}$) relevant to fusion power plants. SPARC's place in the path to commercial fusion energy, its parameters and the current status of SPARC design work are presented. This work also describes the basis for global performance projections and summarizes some of the physics analysis that is presented in greater detail in the companion articles of this collection.
SPARC is being designed to operate with a normalized beta of 
$\beta _N=1.0$, a normalized density of 
$n_G=0.37$ and a safety factor of 
$q_{95}\approx 3.4$, providing a comfortable margin to their respective disruption limits. Further, a low beta poloidal 
$\beta _p=0.19$ at the safety factor 
$q=2$ surface reduces the drive for neoclassical tearing modes, which together with a frozen-in classically stable current profile might allow access to a robustly tearing-free operating space. Although the inherent stability is expected to reduce the frequency of disruptions, the disruption loading is comparable to and in some cases higher than that of ITER. The machine is being designed to withstand the predicted unmitigated axisymmetric halo current forces up to 50 MN and similarly large loads from eddy currents forced to flow poloidally in the vacuum vessel. Runaway electron (RE) simulations using GO+CODE show high flattop-to-RE current conversions in the absence of seed losses, although NIMROD modelling predicts losses of 
${\sim }80$ %; self-consistent modelling is ongoing. A passive RE mitigation coil designed to drive stochastic RE losses is being considered and COMSOL modelling predicts peak normalized fields at the plasma of order 
$10^{-2}$ that rises linearly with a change in the plasma current. Massive material injection is planned to reduce the disruption loading. A data-driven approach to predict an oncoming disruption and trigger mitigation is discussed.
