Student: Mekki Rofaida Nihed
Supervisor: Prof. RNDr. Milan Tichý, DrSc.
ConsultantDoc. Mgr. Pavel Kudrna, Dr., Mgr. Martin Čada, Ph.D. (FzÚ AV ČR)
Status: Assigned
Abstract:
Liquid metals plasma facing components in tokamak devices are highly resistant and simultaneously act as a cooling medium. Liquid metal tokamak divertors using lithium or tin are planned for ITER as well as for DEMO tokamaks. Tin (Sn) is a good candidate due to its low vapor pressure, low reactivity with hydrogen and good resilience to neutron impact. A disadvantage is higher impurity influx into the plasma and condensation of the metal vapors on the tokamak wall. Cleaning the deposit off the vessel walls presents a problem that must be solved in systems using a liquid metal tokamak divertor.
The goal of the proposed work is a systematic study of the behavior of the solid Sn sample exposed to the low-temperature flowing discharge plasma in rare and molecular gases, e.g. Ar, N2, with a focus on tin erosion and/or re-deposition. Samples will be prepared by evaporation or magnetron sputtering of Sn on stainless-steel substrates in a high vacuum system separated from the discharge vacuum vessel and then exposed to the flowing high density discharge plasma. The prepared as well as the processed samples will be studied using the surface analysis methods.
For the study will be used the UHV system with generation of low-temperature plasma by a plasma-jet, magnetron and a thermionic cathode; see figure. The needed experimental equipment in our laboratory is fully functional. The topic was proposed for financing to the Czech Science Foundation.
Literature:
[1] J. Čečrdle, Simulation of behavior of liquid metal divertor heat shield on tokamak COMPASS Upgrade, Czech Technical University, Master thesis 2021.
[2] J. Horacek et al. Phys. Scr. 96 (2021) 124013.
[3] A. Manhard et al., Nucl. Fusion 60 106007 (2020).
[4] W. Ou et al., Nucl. Fusion 61 (2021) 066030.
[5] Lieberman M.A., Lichtenberg A.J., Principles of Plasma Discharges and Material Processing, John Wiley and Sons, Inc., 2005, ISBN 0-471-72001-1.
Other papers will be recommended by the supervisor