Low-Temperature H2/D2 Plasma–W Material Interaction and W Dust Production for Fusion-Related Studies

Abstract

In this paper, results concerning hydrogen and deuterium plasma (RF, 13.56 MHz) interactions with tungsten surfaces, were reported. We used the Hollow-Cathode (HC) configuration for plasma–tungsten surface interaction experiments, along with the collection of tungsten dust, at different distances. Further on, the plasma-exposed tungsten surfaces and the collected dust were morphologically analyzed by contact profilometry, scanning electron microscopy, and energy dispersive spectroscopy measurements, along with chemical investigations by the X-ray photoelectron spectroscopy technique. The results showed that exposing the tungsten surfaces to the hydrogen plasma induces surface erosion phenomena along with the formation of dust and interconnected W structures. Herein, the mean ejected material volume was ~1.1 × 105 µm3. Deuterium plasma facilitated the formation of blisters at the surface level. For this case, the mean ejected material volume was ~3.3 × 104 µm3. For both plasma types, tungsten dust within nano- and micrometer sizes could be collected. The current study offers a perspective of lab-scaled plasma systems, which are capable of producing tungsten fusion-like surfaces and dust.

Tungsten Material Behavior under H2, D2, and He Plasma Interaction Conditions in the Framework of Fusion-Relevant Studies

“…The experimental system consisted of a hollow-cathode (HC) assembly [29] with a dust collector attached, which was placed inside a HydraCool vacuum chamber (water-cooled). The HC assembly was composed of two parallel tungsten plates (with a purity of 99.97%, PLANSEE supplier) with a 3 mm distance between them (Figure 1a).…”

“…Furthermore, the plasma discharge was investigated using two methods: optical emission spectroscopy, and the single probe Langmuir method. The current study represents a continuation of our previous experiments [28,29] in order to achieve a method for stable, fast, and low-cost experiments which are suitable for obtaining fusion-relevant materials. The paper is divided into five sections: the Introduction (comprising the state of the art of the discussed subject), Materials and Methods (in which details regarding the procedure, the materials used, and methods are included), Experimental Results (showing the obtained results), Discussion (in which the occurring phenomena are debated), and Conclusions (in which the conclusions of the current study and suggestions for future experiments are expressed).…”