First results from dust detection during plasma discharges on Tore Supra

Abstract

In-vessel dust has been recognized as a safety and operational issue for next-step devices such as ITER. As a consequence, it is essential to develop methods for dust detection and dust removal. An electrostatic dust detector has been developed by Princeton Plasma Physics Laboratory (PPPL) to detect dust particles on a remote surface and provide locally real-time information on dust generation. A set of these dust detectors has been installed and tested in one of the pumping ducts of Tore Supra. A total of 481 shots from the plasma campaign in late 2010 have been analyzed. The dust signals from the detector and the particles observed on the visible CCD images have been investigated and exhibited good correlation. Dust particles are typically detected for about 5 s after a plasma disruption. Sometimes dust particles are detected during plasma current ramp-up on shots following a disruption. Finally, it is shown that 82% of the dust particles detected are due to disruptions and that the quantity of dust particles increases with the severity of the disruption.