A. Rack

A blast wave slams into a surface, and the surface starts to wrinkle like a carpet when you drag your foot across it. These wrinkles grow, curl into vortices, and stir everything around. In fusion, such mixing is a big problem: the fuel doesn't compress evenly, and the reaction fizzles out. Physicists have found a way to stop this process without touching the wave itself.

Conventional X-ray fluorescence analysis works like a meticulous scribe: to learn the composition of a picture, it walks over every square centimeter and logs whether lead or copper is present. For a flat sheet, that's tolerable, but for a three-dimensional object, it's torture.