First mirrors for diagnostic systems of an experimental fusion reactor II. The mirror tests on the large fusion devices under operation

Abstract

In part II of this review, the results of experiments on the exposure of mirrors in the operating fusion devices are described (we restricted the results to those that had been obtained up to the end of 2004). It is shown that in the locations that are suitable for the positions of the mirrors (at the ports and divertor), as well as near the carbon graphite limiters, the appearance of deposits predominates. However, there are also regions in the vacuum vessel where the main effect is mirror sputtering. In this connection, two methods of mirror cleaning that can possibly be used in situ are described: by a gas-discharge low-temperature plasma and by repeated laser shots. Also, the effect of multiple-shot laser illumination on the survivability of metallic mirrors of laser diagnostics is analysed.