Experimental study of PFCs erosion and eroded material deposition under ITER-like transient loads at the plasma gun facility QSPA-T

The paper concerns experimental investigations of plasma facing components erosion under the plasma heat loads expected in ITER divertor during transient events such as the Type I Edge-Localized Modes and the disruptions. The experiments were carried out at the TRINITI plasma gun QSPA-T. The carbon fiber composite and tungsten macrobrush targets designed for ITER were exposed to multiple plasma pulses of duration 0.5 ms and deposited energy in the range of 0.2-2.5 MJ/m2. Between some of the pulses the eroded surface was analyzed with profilometric measurements and electron microscopy. The CFC erosion is determined mainly by damages to the PAN-fibers. While the energy increases from 0.2 to 2.4 MJ/m2 the removed layer of PAN-fibers area increases from 0.01 to 10 μm per pulse. The erosion of tungsten (pure and lanthanum oxide-doped tungsten) is shown to be determined mainly by crack formation, melt layer movement and droplets ejection.