Dave Shaw

University Of York

I have been working under the supervision of Dr Erik Wagenaars in deposition removal from fusion optics. This is a project involving both simulation and experimental work at the University of York.

Fusion devices, especially the next generation such as ITER, will depend on their optical diagnostics for both research and real time operational control. All optical diagnostics in these devices will rely on a plasma facing metallic mirror which will undergo erosion from the plasma, and deposition of surrounding wall material that has also been eroded. Erosion is combated fairly easily using the crystal structure of the mirror however only 10 nm of deposited wall can severely degrade the quality of the optical signal. The mirrors in ITER will be stainless steel, molybdenum, or rhodium coated molybdenum. The wall of ITER will be beryllium with a tungsten divertor. By powering these mirrors as a CCP discharge and forming a DC bias the depositions on the mirrors can be sputtered away using ion bombardment from the formed plasma. My research is into how well this process will work and what optimisation of the plasma can be performed in order to assist in the process.