The Princeton Plasma Physics Laboratory (PPPL) has put forward a new theoretical model for fusion power experiments, which recommends compressing the plasma gas only after superheating it first. This order of operating, which largely reverses the way many experiments are carried out now, will dramatically reduce the energy input necessary to achieve fusion “ignition,” or sustained burning within a plasma, according to one published interpretation of the study.

Fusion “ignition” refers to a greater output of energy than the energy input into the plasma, as occurred for the first time in 2022, with a number of repetitions since, at the Lawrence Livermore National Laboratory’s National Ignition Facility, a laser-fusion experiment. Extreme compression of the plasma—usually attempted before the gas has been superheated—has proven to be the most difficult condition to achieve and sustain. In most of the newest experiments, at least in labs in the United States, the plasma gas is compressed first, or, as with “colliding beam” experiments, superheating and compression are assumed to be occurring at the same time within the plasma.

This study, while it suggests that the Lawson “triple product” criterion of heat/density/time may be an easier mountain to scale than previously thought, also suggests that experiment plans should be altered to get there.