In situ microscopy for plasma erosion of complex surfaces.

A novel method for the in situ visualization and profilometry of a plasma-facing surface is demonstrated using a long-distance microscope. The technique provides valuable in situ monitoring of the microscopic temporal and morphological evolution of a material surface subject to plasma-surface interactions, such as ion-induced sputter erosion. Focus variation of image stacks enables height surface profilometry, which allows a depth of field beyond the limits associated with high magnification.