CER SEMINAR


Helium plasma irradiation to metals : effects on fusion reactor and industrial application

Shin Kajita, IMaSS (Institute of Materials and Systems for Sustainability), Nagoya University
September 22, 2017, 1:00pm - 2:00pm, EBU-II 479

   

ABSTRACT:

Helium plasma irradiation to metals leads to the growth of fuzzy nanostructures on various metals. He bubble growth is involved in the formation of fuzz, and shear modulus is likely to be an important parameter to control the surface morphology change. The size number relation of He bubbles has fractal feature, and, moreover, the fuzzy nano-structures have multi-fractality. In fusion devices, there is a possibility that the nanostructures were grown by the exposure to He ions. Since the thermal conductivity decreased by two orders of magnitude, anomalous temperature increase can occur in response to transients, leading to melting, arcing, and so on. In linear plasma devices, initiation of unipolar arcing has been identified on the nanostructured W in response to transients. Although it may be unwelcome for fusion reactor material, it can have a great potential for application. One of the potential applications is for photocatalysis. It can be highly active photocataltic materials.

   

BIO:

Shin Kajita received his Doctor's degree ('05) from the University of Tokyo, and has been an associate professor at Nagoya University since 2008. Dr. Kajita has been working on development of laser diagnostics in a linear plasma device and Thomson scattering measurement system in ITER (International Thermonuclear Experimental Reactor). He also investigates plasma material interaction phenomena in nuclear fusion reactors. His field of research also includes plasma diagnostics using spectroscopy and laser, plasma material interaction, arcing in nuclear fusion reactor, and fabrication and application of nanostructure metals. 

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