In burning plasmas, the energy from charged particles created by fusion reactions compensates for heat loss. Burning plasmas power the Sun and other stars, and they could provide abundant energy for humankind. In the Sun, proton fuel is used in fusion reactions. But on Earth, the highest performance fuel is composed of deuterium and tritium ions. Scientists have several ways of producing fusion energy in the laboratory, most notably through magnetic and inertial confinement.

The progress made on magnetic fusion has led to the planning and construction of ITER, the international fusion research facility. Significant fusion power has been achieved for a little less than a second in magnetically confined plasmas—up to 10 MW in the Tokamak Fusion Test Reactor in the US1 and up to 16 MW in the Joint European Torus in the UK.2 In those experiments, the deuterium–tritium fuel is self-heated by fusion products—alpha particles—which...

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