Characterization of dust produced during the 2021 first campaign in EAST tokamak

Abstract

• The dust collected from 2021 first experimental campaign in EAST was characterized and analyzed. • By using the diagnostic observation window, dust was collected during the campaign for several times. The local dust production rate decreases as the plasma operation goes. • Ferromagnetic dust with the shape of strips, flakes, irregular blocks and spheroids has been found in EAST. Dust has been collected and characterized by various methods during the 2021 first experimental campaign in EAST tokamak. It was found that the weight of the in-vessel dust collected at the mid-plane port varied from about 265 mg to about 966 mg. And the dust appeared mainly in the shape of spheroids, flakes, stripes and irregular-shaped particles with the sizes ranging from micrometers to several millimeters. The dust consisted of different elements, which was from the wall-conditioning, erosion of plasma-facing materials (PFMs) as well as the flaking of deposits. The dust collected from the lower port K contained different elements from those collected from the in-vessel port K, with more Fe in the lower port and more Li in the vacuum vessel. The ferromagnetic dust with different shape has been found, and different shape has different O content and size. By using the diagnostic observation window, dust was firstly collected during the campaign and the local dust production rate is calculated, which is found to decrease as the plasma operation goes.