Stuck in the rough: How aging reactor walls may exhibit lower erosion

As plasma circulates in a fusion device, the surface of the device that faces the plasma erodes. This releases particles of surface material. Most erosion occurs through a process called sputtering, where a particle strikes a surface and results in the ejection of atoms from that surface. The number of atoms eroded for each incident particle, known as the sputtering yield, varies depending on the angle at which the incident particle contacts the surface.