Dust creation and transport in MAST

摘要

In this contribution, we report on experiments performed in MAST to investigate dust creation, transport and influence on plasma performance. The exceptional diagnostic access of MAST allows stereoscopic imaging of dust particles' motion in both the divertor and the main chamber, utilizing fast infrared cameras. This technique allows the 3D trajectory of the particles to be reconstructed. Infrared imaging of dust creation during disruptions revealed an isotropic release of dust particles from the surface with very high velocities (up to 350 ms~(-1)). Stereoscopic imaging has been used to study, for the first time, the mobilization and transport in the divertor plasmas of carbon and tungsten particles with known size distributions, which were introduced into the vessel through a divertor probe. A correlation between the carbon particle size and acceleration by the plasma is observed. Tungsten particles are found to move with lower velocities and experience lower acceleration and are found to be more prone to vertical motion towards the core plasma. In the case of large particles this can lead to early disruptions. Modelling of the dust injection experiments has been conducted using the DTOKS code in an attempt to validate the transport equations employed in the simulation.