US fusion ignition propels with THOR's 'burning plasma' breakthrough

A collaborative research effort led by Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratory (LLNL) achieved a significant fusion ignition breakthrough using LANL’s new Thinned Hohlraum Optimization for Radflow (THOR) window system. Conducted on June 22, 2025, at the National Ignition Facility (NIF), the experiment generated a fusion energy yield of 2.4±0.09 megajoules and produced a self-sustaining fusion reaction, confirming that ignition is possible even when the hohlraum is modified to allow X-rays to escape for diagnostic purposes. This success validates high-fidelity 3D simulations and demonstrates that fusion ignition can be maintained despite the energy loss and asymmetry challenges introduced by the THOR windows. The THOR system modifies the conventional NIF hohlraum by incorporating windows around its equator, enabling some X-rays to exit and irradiate test materials. This innovation allows scientists to study material responses