Investigation of tokamak T-10 globular films microstructure.

Institute for Theoretical and Experimental Physics, Moscow, Russia Introduction Inevitable consequences of graphite limiter utilization in ITER are hydrocarbon films formation on vacuum vessel elements. Therefore one of the key processes, determine of reactor ITER economy in use, is tritium absorption of these films . As it was mentioned earlier [1] in the vacuum chamber of tokamak T-10 have been found out carbon globular films and flakes with friable structure and with big ratio of D/C~0.8. Investigations of this films all over again on an scanning electron microscope (SEM), and then on stationary scanning tunneling (STM) and atomic force (AFM) microscopes, has found out fractality of a surface microstructures, from the characteristic dimentions ~ 100 microns and till the dimentions ~ 10 nanometers. In the report results of research of a surface and internal globular films structure, estimation of a surface fractal dimension, model of films growth are submitted, the reasons of occurrence of such structure are discussed. Experimental conditions for globular films generation. Globular films have been found in two operating modes of T-10 tokamak. It improved confinement mode, in which big carbon flux originated from an internal part of a circular graphite limiter, under action of sputtaring by arcing [2]. And as in a mode without a circular graphite limiter where carbon recycling on a plasma periphery increase on the order of value. Fractal analysis of a globular films surface. The analysis of a surface was carried out by various type of microscope – SEM, STM and a b c d Fig.1. Films images with full size: a-300µm, b-5µm, c-1µm, d-50nm,