Researchers report longest-running fusion plasma yet
An experimental reactor sustained a plasma for over six minutes, a mark researchers said marked a step toward steady-state operation.
Key points
- Plasma sustained for over six minutes
- Temperature held above 50 million degrees Celsius
- Net energy gain was not achieved
- Full results to be published next month
Why it mattersLong-duration plasmas are one of the hardest remaining problems on the path to commercial fusion, so any step toward steady-state operation matters.
A research team reported on Thursday that their experimental reactor sustained a fusion plasma for more than six minutes, the longest duration achieved at that facility.
Nature reported that the experiment, conducted at a European tokamak, maintained a plasma temperature above 50 million degrees Celsius throughout the run. Researchers said the result demonstrated progress toward steady-state operation, a prerequisite for a working power plant.
The team cautioned that the result was a scientific milestone, not an engineering one. Net energy gain, the point at which a reactor produces more energy than it consumes, was not achieved.
Several competing approaches, including private ventures using different designs, are racing to demonstrate longer and hotter plasmas. The field has attracted renewed public and private investment.
A full account of the experiment will be published next month, the team said.
Reported by
- Nature — Tokamak sustains plasma for record six minutes · 2026-08-28T18:00:00Z
- Reuters — Researchers report fusion plasma duration record · 2026-08-28T18:30:00Z