Mainz 2022 – scientific programme
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P: Fachverband Plasmaphysik
P 9: Poster I
P 9.19: Poster
Tuesday, March 29, 2022, 16:00–17:30, P
Experimental investigation of velocities and diameters of droplets generated by arcing — •Alberto Castillo Castillo1,2, Martin Balden1, Volker Rohde1, and Rudolf Neu1,2 — 1Max-Planck Institute for Plasma Physics (IPP), Garching, Germany — 2Technical University Munich (TUM), Garching, Germany
Droplet generation by arcing is one of the mechanisms that can generate dust in a fusion device. The metal droplets expelled by the arc can potentially introduce impurities in the plasma core and influence the operation of the device. The aim of this work is to study the velocities, diameters and direction of the droplets expelled by arcing from a metal target. Knowing the sizes and velocities distribution of the droplets would allow an estimation of their influence on plasma operation. Different target materials will be used relevant to fusion devices, with a focus on tungsten.
The experimental setup consist of a vacuum chamber in which an arc is ignited on a target. After an arcing event, the droplets expelled within a certain solid angle enter a vertical drift tube. Along the tube, the droplets pass through the line of sight of two detection systems. Each detector measures the light scattered by the droplet from a perpendicular light source. The amplitude of the signal can be converted to droplet diameter through the application of MIE scatter theory, and the signal length and time delay between both sensors allow the calculation of velocity. The orientation of the target is changed in order to measure the distributions of droplets expelled at different angles.