The nuclear fusion breakthrough that wasn’t

There was recently a nuclear fusion “breakthrough” which I just had to check out. I was disappointed to learn that this wasn’t a breakthrough at all, but a clever bit of marketing dressing up a modest scientific experiment. To explain what happened, a laboratory used around 300 megajoules of energy to create a 2 megajoule laser pulse. That pulse then hit a pellet of material, releasing 3 megajoules of energy as the pellet underwent nuclear fusion. The holy grail of fusion is a self-sustaining reaction, one necessity of such a reaction is that more energy must be released than is put in, and this experiment was hails as doing just that since the 3 megajoules of released energy is more than the 2 megajoule laser pulse. Yet that isn’t actually true because 300 megajoules went into creating that laser pulse, this is like saying a company is profitable if you ignore all salary costs. At the end of the day we want to develop a fusion reaction such that energy out > energy in, and this reaction simply did not do that.

I know why they tried to spin it this way, it’s a longstanding trick of pulsed-laser experiments to report only the amount of energy delivered by the laser, ignoring the amount of energy it takes to create that laser pulse. It makes your reactions seem a lot more efficient and feasible than they really are. But this kind of lying does the entire industry a disservice because it’s just more evidence on the pile of fusion-boosters overpromising and underdelivering. Reading this news you’d mistakenly believe we are now on the precipice of economical and available fusion power when in actuality we’re about as far as we’ve always been.

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