Formation of dust particles and clusters is observed in almost all modern fusion devices. Accumulation of dust in next-generation thermonuclear installations can significantly affect plasma ...parameters and lead to accumulation of unacceptably large amounts of tritium. The use of a specially developed electrostatic probe is planned in the international thermonuclear experimental reactor ITER to collect dust for further analysis. The article describes a numerical model of movement of dust particles in an electrostatic probe. Dust particle trajectories inside the probe are analyzed. Several electrostatic probe design modifications are proposed on the basis of the analysis in order to increase the efficiency of dust collection.
Tungsten is going to be implemented as a material for plasma-facing divertor tiles in an ITER tokamak. Accumulation of dust particles due to exfoliation of redeposited tungsten layers can severely ...affect the operation of a fusion devices. Behaviour of tungsten films deposited on tungsten, including layers with added impurities of iron (0,2 at.% and 2 at.% concentration), as well as dust particles with Al impurity, has been studied. It is shown that a film with 2 at.% impurity of iron exhibits exfoliation and blistering when exposed to thermal and radiation loads, while tungsten dust particles with aluminium impurity undergo various structural changes depending on their Al content when heated.
Formation of dust particles and clusters is observed in almost all modern fusion devices. Accumulation of dust in next-generation thermonuclear installations can significantly affect plasma ...parameters and lead to accumulation of unacceptably large amounts of tritium. The use of a specially developed electrostatic probe is planned in the international thermonuclear experimental reactor ITER to collect dust for further analysis. The article describes a numerical model of dust particles movement in an electrostatic probe. Dust particles trajectories inside the probe were analyzed. Several electrostatic probe design modifications were proposed on the basis of the analysis in order to increase the efficiency of dust collection.
Formation of dust particles and clusters is observed in almost every modern thermonuclear facility. Accumulation of dust in the next generation thermonuclear installations can dramatically affect the ...plasma parameters and lead to the accumulation of unacceptably large amounts of tritium. Experiments on collection of dust particles by a model of electrostatic probe developed for collection of metallic dust at ITER are described in the article. Experiments on the generation of tungsten dust consisting of flakes formed during the destruction of tungsten layers formed on the walls of the plasma chamber sputtered from the surface of the tungsten target by plasma ions were conducted. The nature of dust degassing at elevated temperatures and the behavior of dust in an electric field were studied. The results obtained are compared with the results of the experiments with dust consisting of crystal particles of simple geometric shapes. The effectiveness of collection of both types of dust using the model of an electrostatic probe is determined.
In the paper, a simple and easy to operate stand is presented that allows irradiating the surface of solids by gas discharge plasma ions in the energies ranging from 5 to 40 keV. The results of first ...experiments are shown. Ion current parameters on the irradiated sample using gas discharge are presented for different gases.
A brief overview of the high heat flux material testing facilities is presented which forms background for a new small-scale laboratory device capable of high heat flux material testing. The scheme ...of the device is presented and its working principles are described. High heat and particle loads are achieved by focusing of either electron or ion beam on the sample being tested. The sample is fixed to an actively cooled copper table. Experiments with hydrogen ion beam irradiation of an MPG-8 graphite sample are presented, in which heat loads of 270 MW/m2 were achieved. SEM images of the sample surface after testing are presented.
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