Proof-of-principle experiments on the particle control capability of the moving -surface plasma-facing component concept.

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Because it is well known that high-performance core plasma favors low wall recycling conditions, a number of existing magnetic fusion experiments employ wall conditioning techniques such as boronization. However, by nature these wall conditioning techniques have finite lifetime of efficacy due to the surface saturation with implanted fuel and impurity particles. It follows immediately from this that for future steady state fusion devices, enabling wall concepts must be developed to maintain surfaces of plasma-facing components (PFCs) unsaturated under steady state plasma interaction conditions.In this research program, a new concept of PFC, employing a water-cooled rotating drum intended to maintain particle recycling <100% has been examined using a steady state linearly magnetized plasma device. Under plasma bombardment with densities around 10^<11> 1/cc and electron temperatures around 10 eV, the rotating drum was continuously Bettered with titanium, at deposition rates around 10Å/s and the intensity of H_α was monitored with spectroscopy. Experimental results indicate that hydrogen recycling is reduced down to 94% even at steady state. A zero-dimensional particle balance model has been developed and reproduced the experimental data quite well using conservative literature data substituted into it.As the next step, to examine the possible use of flowing liquid (metals) as a PFC, the experimental facility has been modified in such a way that the plasma flow can be directed either horizontally or vertically. Because this is a one-of-a-kind facility, and has been reported in a couple of nation-wide circulated newspaper. The present status of this facility is that all the plasma diagnostics have been tested for their own functions and the first liquid lithium experiments have been done.