Liquid metal as the wall material of fusion reactors: deuterium retention and surface stability

Index of supplementary videos

An index of each supplementary video can be found below. For easier accessibility the videos have been reduced in size and compressed.

Supplementary Video S-4.1 shows a gif video of the ejection of a Sn droplet from free liquid Sn surface exposed to argon plasma in Nano-PSI.

Supplementary Video S-4.2 displays a video of free liquid Sn surface exposed to hydrogen plasma Nano-PSI. In the begin of the video, a impurity layer floated on the surface can be seen clearly and quickly disappears either by being ejected out or flowing away. During the whole exposure process, too many droplets are observed.

Supplementary Video S-4.3 shows a video of free liquid Sn surface exposed to nitrogen plasma in Nano-PSI. In the first ~ 22 s, the surface remained stable without any droplets, while from ~ 22 s forward, the surface is slowly getting quite unstable and too many droplets are ejected out until the end of the exposure. 

Supplementary Video S-4.4 is a part of video from CPS liquid Sn exposed to hydrogen plasma in Nano-PSI, where liquid Sn has been repelled out of the meshes and a Sn pool can be seen on the top. The central area of the pool seems quite clean and is with less droplets, while an impurity layer seems to exist on the edge part of the pool and is with more droplets. 

Supplementary Video S-4.5 is a part of video from CPS liquid Sn exposed to nitrogen plasma in Nano-PSI. A small Sn pool can be also observed above the meshes and droplets are ejected out randomly from the surface.

Supplementary Video S-4.6 is a video of CPS liquid Sn exposed to hydrogen plasma in Magnum-PSI. A lot of droplets can be seen in the video. Some of these droplets are repelled and brought back onto the surface either by plasma pressure or magnetic field once they are ionized, while droplets just fall down possibly due to gravity.

Supplementary Video S-4.7 is a video of CPS liquid Sn exposed to helium plasma in Magnum-PSI. Compared with Sn exposed to H plasma, much less droplets are observed in the video.

Supplementary Video S-4.8 is a video of CPS liquid Sn exposed to deuterium plasma in Magnum-PSI. Too many droplets can be observed and an alternate expanding and shrinking glowing area on the surface center can be also seen. This is presumably due to the alternate expanding and shrinking of the CPS meshes resulting from gas bubble formation.

Supplementary Video S-4.9 shows a video of an ejected TZM cup filled with Sn exposed to hydrogen plasma in Nano-PSI. It can be seen that the Sn in the cup was not totally melted while the surface of the melted part already exhibited unstable. The reason why the cup was ejected up is because that there was a big gap between the cup and the target holder. In the previous exposure, some liqud Sn was pushed out of the cup and flowed into the gap. As the whole target holder was also soaked in the hydrogen plasma, the pressure in the gap increased due to more and more hydrogen desorbing from liquid Sn and finally this high pressure made the cup suddenly eject up.