Electrohydrodynamic Instability in Liquid Metal Plasma-Facing Components
Abstract
A critical issue for liquid metal plasma-facing components (PFCs) is the stability of the liquid metal surface in the presence of a plasma. Recent investigations at Pilot-PSI and TEXTOR have observed strong, unexplained droplet emission from liquid tin surfaces confined by a porous mesh, a setup known as a capillary porous system (CPS). Electrohydrodynamic (EHD) instability caused by the plasma sheath electric field is investigated as a potential mechanism for droplet emission in liquid metal PFCs. The relation between the critical electric field Ec required for the onset of an EHD instability and the wavelength of the instability is presented. Predicted values of Ec for both free surfaces and CPS of various liquid metals are compared with typical values of the electric field at the sheath edge. To check these predictions, the results of an experiment to measure Ec for droplet emission for both a free surface and a CPS of liquid gallium will be reported.
Work supported by U.S. DOE Contract DE-AC02-09CH11466 and by the Princeton Environmental Institute.- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2014
- Bibcode:
- 2014APS..DPPJP8016F