USA STUDY OF CHANGES IN MICROHARDNESS AND MASS OF A PREHEATED TUNGSTEN UNDER THE INFLUENCE OF PULSED PLASMA

The paper presents the results of an experimental investigation of changes in the microhardness and mass of a preheated tungsten target, the primary candidate material for the first wall and divertor, subjected to a pulsed plasma flow of approximately 0.2 ms duration. The experiments were conducted as a series of 13 pulses, each with an energy density and power density of approximately 1.1 MJ/m² and 5.5 GW/m² , respectively. Microhardness was measured using an HVS-1000B hardness tester; the target mass before and after plasma exposure was measured using a CPA225D precision balance. It is shown that the microhardness of the tungsten target remains virtually unchanged even at the maximum irradiation dose (up to 39 pulses), and the observed change is within the measurement error, which indicates the structural stability of the surface layer. At the same time, an increase in the target mass (up to 31 mg) was recorded, probably caused by contamination and redeposition of the material of external structural components. Energy-dispersive spectroscopy (EDS) analysis revealed Cu, Zn, Ni, and C lines in dust particles redeposited on the target surface. The results indicate that these foreign components have a significant impact on surface morphology and should be considered when interpreting tungsten damage mechanisms.

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