The SPARC ICRF conference papers are two contributions to EPJ Web of Conferences volume 346 (2026) that describe the 📝ion cyclotron resonance heating (ICRH) system 📝SPARC will use to reach fusion-relevant temperatures, and simulate how it should behave in the first campaign.
Maria Usoltseva of Commonwealth Fusion Systems led the system overview (02001, 10.1051/epjconf/202634602001) with Michael Garrett, Erik Johnson and Peter Matthews of CFS and Christina Migliore, Gregory M. Wallace and John C. Wright of the 📝MIT Plasma Science and Fusion Center. It reports 20 MW of installed power at 120 MHz for the first campaign, delivered through four-strap antennas arranged in poloidal pairs, with a matching network designed to accommodate a range of plasma loading conditions and a fast controller that retunes during a pulse using frequency modulation of ±1 MHz. The overview describes ten such antennas; the companion simulation paper describes fourteen antennas at seven toroidal locations delivering more than 20 MW. Both figures are design values for a machine that has not yet produced plasma, not measurements.
Migliore led the second paper (02011, 10.1051/epjconf/202634602011) with Usoltseva and Wright. It applies the Stix full-wave cold-plasma solver, extended with lower-order thermal corrections so that wave–particle resonances — Landau damping and ion resonances in the core — can be resolved rather than approximated, to first-campaign and primary-reference-like discharges. Because SPARC's 📝toroidal field is high, the resonance layers sit at frequencies well above those of most operating tokamaks, which is why the modelling work is not simply inherited from elsewhere.
Both papers extend the design work in the SPARC physics basis: 📝Yijun Lin, Wright and Stephen Wukitch published "Physics basis for the ICRF system of the SPARC tokamak" in the Journal of Plasma Physics 86(5) in 2020 (10.1017/S0022377820001269), which established the 📝RF heating scheme these two papers now carry into engineering detail.
Twenty megawatts at 120 megahertz is how we intend to get SPARC's ions hot enough to burn. These two 2026 conference papers are where the antenna and matching design meet the full-wave simulations that predict what the plasma will absorb.