First experiments with lithium limiter on FTU

摘要

A liquid lithium limiter (LLL) with capillary porous system has been tested for the first time on the high field medium size tokamak, FTU. Lithium acts as a first wall material in the liquid phase and as a conditioning technique by depositing a lithium film on the walls (lithization). Thermal loads exceeding 5 MW/m(2) have been so far applied to the LLL surface during plasma discharges: no anomalous Li influx, like 'lithium bloom', occurs and no surface damage is observed, even after plasma disruptions. Radiation losses, plasma contamination and working gas recycling are reduced after Li coating of the wall as for boronization but with better results. A large electron temperature increase (similar to 50%) in the scrape-off layer occurs that is well reproduced by the simulation of 2D code TECXY. The Greenwald density limit is easily reached and even exceeded in the explored plasma current ranges (I-p = 0.50-0.9 MA). (c) 2007 Elsevier B.V. All rights reserved.