Compact Experimental Negative TriAngUlarity Reactor (CENTAUR): Design Study for a Breakeven Negative Triangularity Device

The Compact Experimental Negative TriAngUlarity Reactor (CENTAUR) is the product of the collaborative Fall 2024 Fusion Design course offered at Columbia with participants from Columbia and Princeton University. The goal of the course was to produce a next-step, breakeven negative triangularity tokamak that could be constructed with existing technology. CENTAUR is predicted to achieve net fusion gain (Q>1) at low capital cost and is materially robust to a lifetime of scientific use. The device remains compact, with a major radius of 2.0 m, while high-temperature superconducting magnets enable a magnetic field of 10.9 T on-axis. Optimized divertor geometry and significant radiated power fraction, enabled by negative triangularity plasma shaping, in the edge allow high power density in the device without necessitating advanced divertor concepts. Mechanical stress and neutron modeling suggest CENTAUR's magnetic systems and vacuum vessels will withstand operational stresses, including robustness to at least 10,000 vertically unstable full-current quenches. Costing models estimate a total operational cost below $2 billion.