Inside JET's torus, with superimposed plasma. (UKAEA) Late last century, the Joint European Torus (JET) near Oxford, UK, churned out 22 megajoules of energy in what was, at the time, a record in fusion power. Now, experimental upgrades have brought the facility into line with the technology anticipated for a major international project, resulting in the production of nearly three times that amount of power. The advances are a major step forward for tokamak-based fusion, bringing us ever closer to a balance point where we can harvest a near endless stream of energy without the cost of polluting emissions or...