Model of fuzz formation on a tungsten surface

Tailoring molybdenum nanostructure evolution by low-energy He+ ion irradiation

“…To gain a better understanding of the physical mechanism behind this, a series of experiments have been performed extensively in a tokamak environment and/or in laboratory accelerator systems, using comparatively low-energy H and He ions [7,10,[12][13][14][15][16]. However, the physical mechanism responsible for the deterioration is not yet very clear, although several modeling and simulation approaches, e.g., molecular dynamic, multiscale, and atomistic, have also been tried [17][18][19][20][21][22][23][24]. An understanding of the material properties in a fusion environment is essential for better operation, safety, and performance of fusion reactors.…”

Dynamic measurement of the helium concentration of evolving tungsten nanostructures using Elastic Recoil Detection during plasma exposure

“…The presence of high pressure He certainly provides stresses to sustain W fuzz development. Also, the bubbles deform the surface, creating trapping sites for W adatoms [4]. In the low temperature regime, the W does not readily move around the He bubbles so fuzz is not created.…”

“…If W fuzz is a desired surface modification from an engineering point-of-view, understanding the growth mechanisms might serve to optimize and accelerate specific W fuzz development, or, if not, suppress it. There are two basic premises for modelling W fuzz growth: pressure driven deformation [2] and surface diffusion around deformities [3,4,5]. If bubbles were to burst to deform the surface, pressure would have to build large enough to overcome the yield strength of W. However, many experiments performed on W fuzz after growth have shown that the He bubbles do not retain these required high pressures once the plasma exposure is ceased [6,7].…”

Nanostructure Growth on Rhodium/Ruthenium by the Exposure to He Plasma

“…Although some formation models have been suggested [3][4][5], the fuzz growth mechanism has yet to be explained well, as well as nano tendril bundle (NTB) [6] and large scale nanostructures [7].…”