Response of fusion plasma-facing materials to nanosecond pulses of extreme ultraviolet radiation
| Autor: | Karel Kolacek, Libor Juha, Jaroslav Straus, M. Toufarová, Oleksandr Frolov, Jiri Matejicek, Jiri Schmidt, Monika Vilémová, Aleš Jäger, Koichi Kasuya, Andrey Choukourov |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Scanning electron microscope chemistry.chemical_element Tungsten Condensed Matter Physics Laser 01 natural sciences Focused ion beam Atomic and Molecular Physics and Optics 010305 fluids & plasmas law.invention chemistry.chemical_compound symbols.namesake chemistry law Extreme ultraviolet 0103 physical sciences Silicon carbide symbols Surface layer Electrical and Electronic Engineering Composite material 010306 general physics Raman spectroscopy |
| Zdroj: | Laser and Particle Beams |
| ISSN: | 0263-0346 |
| DOI: | 10.1017/s0263034618000332 |
| Popis: | The experimental study of damage to tungsten (W), molybdenum (Mo), and silicon carbide (SiC) surfaces induced by focused extreme ultraviolet laser radiation (λ ~ 47 nm/~1.5 ns/21–40 µJ) is presented. It was found that W and Mo behaved similarly: during the first shot, the damaged area is covered by melted and re-solidified material, in which circular holes appear – residua of just opened pores/bubbles, from which pressurized gas/vapors escaped. Next cracks and ruptures appear and the W has a tendency to delaminate its surface layer. Contrary, single-crystalline SiC has negligible porosity and sublimates; therefore, no escape of “pressurized” gas and no accompanying effects take place. Moreover, SiC at sublimating temperature decomposes to elements; therefore, the smooth crater morphology can be related to local laser energy density above ablation threshold. When more shots are accumulated, in all three investigated materials, the crater depth increases non-linearly with number of these shots. The surface morphology was investigated by an atomic force microscope, the surface structure was imaged by a scanning electron microscope (SEM), and the structure below the surface was visualized by SEM directed into a trench that is milled by focused ion beam. Additionally, structural changes in SiC were revealed by Raman spectroscopy. |
| Databáze: | OpenAIRE |
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