Speaker
Mr
Kevin Woller
(Massachusetts Institute of Technology)
Description
Helium (He) ion energy modulation is demonstrated, for the first time, to affect the development of the tungsten (W) nano-tendril morphology that results from He irradiation. Dramatically isolated nano-tendril bundles (NTBs) grow from the surface instead of a uniform nano-tendril layer, or so called fuzz, leaving ~90% of the surface without nano-tendril growth at all. The growth parameters for NTBs are the same as for fuzz except for the radiofrequency modulation of the ion energy. Analyses of the newly discovered NTB growth regime strongly support models of nano-tendril growth that take adatom kinetics as their basis. Additional modeling of the ion energy distribution function of the ITER divertor must take place in order to assess the scope of nano-tendril growth that might occur, and of what type. Through mass loss measurements and electron microscopy, the minimally supported NTBs are shown to be a greater threat to plasma-facing component erosion and dust production than previously observed for uniform fuzz.
| Country or International Organization | United States of America |
|---|---|
| Paper Number | MPT/P5-26 |
Primary author
Mr
Kevin Woller
(Massachusetts Institute of Technology)
Co-authors
Prof.
Dennis Whyte
(MIT Plasma Science Fusion Center)
Graham Wright
(Massachusetts Institute of Technology)
