For the latter part of the 20th century, much of what we knew about plasma fusion came out of Princeton’s Plasma Physics Laboratory. There the massive Tokamak Fusion Test Reactor worked for 15 years, forcing hydrogen atoms together in crazy strong magnetic fields in the search for a sustainable fusion reaction. I wrote a paper about this back in the late 1980s in UC Santa Barbara’s terrific History of the Nuclear Age. Anyhow, the Tokamak was taken offline in 1997, and Princeton says it has now successfully dismantled and removed the leviathan. Just to give you an idea about the machine’s intensity, it was the first to produce more than 10 million watts of fusion power. And in 1995, TFTR attained a world-record temperature of 510 million degrees centigrade — more than 25 times that at the center of the sun.
Incidentally, if you ever wondered what Tokamak means, it’s not — as I once thought — some Native American name or word. It’s actually Russian shorthand describing the squished donut shape of the magnets. To(roidal’naya) kam(era s) ak(sial’nym magnitnym polem), or toroidal chamber with axial magnetic field. Now you know.