Greifswald 2024 – scientific programme
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P: Fachverband Plasmaphysik
P 9: HEPP III
P 9.4: Talk
Tuesday, February 27, 2024, 15:15–15:40, ELP 6: HS 3
Properties of Tungsten Particles Produced by Arcing — •Albertto Castillo Castillo1,2, Martin Balden2, Volker Rohde2, Peter Siemroth3, Michael Laux3, Heinz Pursch3, Juergen Sachtleben3, and Rudolf Neu1,2 — 1Technische Universität München, 85748 Garching, Germany — 2Max-Planck-Institut für Plasmaphysik, 85748 Garching, Germany — 3retired, was with Arc-Precision GmbH, 15711 Königs Wusterhausen, Germany
Metal droplet emission by arcing is one of the mechanisms generating dust in a magnetic confinement fusion device. Tungsten droplet production is of particular interest for full tungsten wall devices. The potential of a droplet to introduce impurities in the plasma depends on its velocity, diameter, and angle. The distributions of these parameters has been measured in a dedicated device with multiple independent methods in order to provide useful data to evaluate their effect on plasma operation.
In a addition to a time-of-flight detection system based on light scattering by droplets to measure their size, velocity and angle, a high-speed camera was added to record videos of the flying droplets. Dedicated software was developed to track the trajectories in the video, and fitting the thermal radiation curves to a model of the cooling of particles allows measurement of diameter and initial temperature. This first measurement of initial temperatures reveals that a significant fraction of particles are ejected in a solid state. This is supported by microscopy analysis of the particle deposition showing non-spherical particles.
Keywords: Arcing, Dust, Droplets, Tungsten