A crystal camera can photograph temperatures hotter than the sun

Inside a fusion reactor, atoms are stripped of their electrons and whipped into a frenzy at 100 million degrees Celsius. At these temperatures, matter becomes a volatile gas called plasma that would melt any physical sensor. To see inside this chaos, engineers at the Princeton Plasma Physics Laboratory developed a camera that uses a single, perfectly tuned crystal to deflect X-rays. This crystal acts like a prism for invisible light, separating wavelengths to reveal the speed and density of the swirling ions.