Dynamics of dust events in the graphite first wall equipped SST-1 tokamak

Dust events are recorded in the SST-1 tokamak with fast visible imaging and infrared imaging systems. The events are analyzed from the image sequences with an in-house developed dust tracking routine in MATLAB called FINDUST. Specific operating scenarios for dust observation and their deleterious effects on discharge evolution are identified. A clear correlation of the dust events frequency and strength with the successful start-up and discharge evolution is observed over eight consecutive experimental campaigns in SST-1. It has been seen that the electron cyclotron resonance heating (ECRH) generated pre-ionization slab annular-plasma around the fundamental layer is most likely to generate dust, while the strongest effect of the ECRH fundamental layer on the plasma facing components is seen when the confined plasma column disrupts by some means while the ECRH pulse is still ON.