To achieve a near tenfold increase in fusion power density, the design makes use of REBCO superconducting tape for its toroidal field coils. This material enables higher magnetic field strength to contain heated plasma in a smaller volume. In theory, fusion power density is proportional to the fourth power of the magnetic field strength. The most probable candidate material is yttrium barium copper oxide, with a design temperature of , allowing various coolants (e.g. liquid hydrogen, liquid neon, or helium gas) instead of the much more complicated liquid helium refrigeration chosen by ITER. The official SPARC brochure displays a YBCO cable section that is commercially available and that should allow fields up to 30 T.
ARC is planned to be a 270 MWe tokamak reactor with a major radius of , a minor radius of , and an on-axis magnetic field of .
The design point has a fusion energy gain factor Q ≈ 13.6 (the plasma produces 13 times more fusion energy than is required to heat it), yet is fully non-inductive, with a bootstrap fraction of ~63%.
The design is enabled by the ~23 T peak field on coil. External current drive is provided by two inboard RF launchers using  of lower hybrid and  of ion cyclotron fast wave power. The resulting current drive provides a steady-state core plasma far from disruptive limits.