Nathan T. Howard is a 🏷️#physicist and principal research scientist at the 📝MIT Plasma Science and Fusion Center, where he leads the Performance and Transport group formed under MIT's collaboration with 📝Commonwealth Fusion Systems. He is lead author of "Performance and transport in the ARC tokamak" (2026), the paper that puts a number on how much power 📝ARC would produce.

Howard's specialty is 📝gyrokinetics — first-principles simulation of the plasma turbulence that governs how quickly heat escapes a 📝tokamak, and therefore how large and how hot a machine must be to reach 📝ignition. His work on multi-scale simulation, for which he received the Nuclear Fusion Award, showed that turbulence at the electron and ion scales interacts rather than acting independently, a coupling that reduced-model predictions had been missing. The 2026 ARC paper scoped a design point at 1.13 gigawatts using zero-dimensional modeling and then tested it against three independent integrated codes — TRANSP, ASTRA and TORAX — which returned a spread of roughly 900 to 1300 megawatts. That spread is the honest content of the result: these are simulation outputs for a machine that does not yet exist, and their agreement with one another is evidence of consistency, not of measurement.