Study of the stochastic clustering on the refractory material surface under the effect of plasma load in the PLM device

Tungsten plates were tested in stationary helium discharges in the PLM device. The duration of discharges in the PLM reached 200 minutes. A distinctive feature of this device is the stationary plasma confinement, which is advantageous for testing fusion materials, including materials of the divertor and first wall of a fusion reactor. During plasma irradiation in the PLM, the thermal load on the surface of the tested plates was more than 1 MW/m2. The temperature of the tested plates amounted to 1000°C and more. Stochastic nanostructures with dimensions of the structural elements of less than 50 nm, including fuzz-type structures, were observed on the processed surfaces of the samples.