Since the article opening sentence and headline don’t say it: The breakthrough is the plasma “triple product,” literally just the plasma temperature (in keV) ti

Since the article opening sentence and headline don’t say it: The breakthrough is the plasma “triple product,” literally just the plasma temperature (in keV) times particle density times (confinement) time. The Lawson Criterion. https://en.wikipedia.org/wiki/Lawson_criterion https://en.wikipedia.org/wiki/Lawson_criterion A useful fusion power plant needs a triple product of at least about 3e12 keV * s * m^-3. They weren’t fusing things (at least, not much). This is a figure of merit that allows you to compare, across all the different fusion methods, how well you would be able to fuse the plasma if you were using burnable fuel such as deuterium and tritium (isotopes of hydrogen that have one or two extra neutrons).