Surface Erosion of Metals under the Effect of Plasma Flows Typical of Transient Processes in Tokamaks

It is shown theoretically that under the effect of plasma flows typical of transient processes in tokamaks not only can Kelvin–Helmholtz instability develop and waves arise on a molten metal surface, pulsating bumps of different sizes also can occur. The formation of bumpy surfaces should be expected at ITER. The maximum possible bump size has been determined. If a bump occurs with a size larger than the maximal one it will be displaced by plasma “wind,” forming streams that flow to the periphery of the region exposed to the plasma flow. These streams transfer the molten metal over the surface. The sizes of bumps whose tops can be blown by the plasma wind, thus causing droplet erosion, were also determined.