(EX/4-5Ra) Study of erosion products in experiments simulating ELMs and disruptions in ITER on plasma gun QSPA-facility

L.N. Khimchenko1), V.M. Gureev1), G. Federici2), S.A. Kamneva1), N.S. Klimov3), V.S. Koidan1), S.N. Korshunov1), B.V. Kuteev1), J. Linke4), A. Loarte5), M. Merola2), V.L. Podkovirov3), A.M. Zhitlukhin3)
1) RRC ``Kurchatov Institute", Moscow, Russian Federation
2) ITER International Team, Garching, Germany
3) SRC RF TRINITI, Troitsk, Russia
4) Association EURATOM, Jülich, Germany
5) EFDA Close Support Unit, Garching, Germany

Abstract.  The experimental date on structure of deposited material from eroded CFC and W macrobrush targets under simulated ITER type I ELMs and disruptions heat loads are presented. Experiments were realized in QSPA plasma gun facility (TRINITI, Troitsk). Macrobrush targets were exposed to a large number of repetitive plasma pulses (up to 100) with heat loads 0.5 - 1.6 MJ/m2 and time duration 0.5 msec. The main result of experiments was effect of fractal ("cauliflower") dust formation for both W and CFC erosion. The typical dimension of dust particles was 0.1-3.0 nm, up to 20 nm, detected by scanning tunneling microscope. Particles size distribution ("scaling") has power-law dependence, i.e. logN = -a*logr , indicate a significant numbers of nanoparticles. For carbon particles a= 2.2, for tungsten - a= 2.3. With decreasing a plasma energy load (0.5 MJ/m2) impact on a CFC target only flakes have been found in the deposits but the amount of dust particles was negligible small. Increasing on a W macrobrush target plasma pulse energy up to 1.6 MJ/m2 reduced to appearance metal droplet.

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