[He built an] actual homemade fusion reactor. Of course, it isn’t actually capable of inducing fusion at this time, as it doesn’t technically emit neutrons. However, the fact that he was able to build it in the first place—and do so in his home for just around $2,000—is really impressive.

What is a fusion reactor that doesn’t induce fusion? What did he build, exactly? And why is it supposed to be impressive?