"A sunburst is similar to a treemap, except it uses a radial layout. The root node of the tree is at the center, with leaves on the circumference. The area (or angle, depending on implementation) of each arc corresponds to its value." Based on this example, see also original example without labels. Labels are problematic but the viz is completely unintelligible without them!
click on outer sections to zoom in, centre circle to zoom out again