Impurity sources and impurity concentrations in FTU
The analysis of impurities in FTU has given special emphasis to the different behaviour of metal and light impurities in the discharge. Due to the poloidal metal limiter and the absence of deliberate low Z deposition on the wall, most of the operation is influenced by the limiter constituents. FTU discharges are characterised by a Z(eff) value decreasing with the line averaged density and increasing with the toroidal plasma current. Previous work has shown that metal impurities, produced by the interaction of the plasma with the limiter, dominate the low density plasmas while at high density only oxygen and carbon lines are detected in the VuV emission of the discharge. In this paper spectroscopic observations in the visible, VUV and soft X-ray spectral regions are exploited to gain a better understanding of impurity sources and to clarify the leading production mechanism.
Bibliographic Reference: Paper presented: 20th EPS Conference on Controlled Fusion and Plasma Physics, Lisboa (PT), July 26-30, 1993
Availability: Available from (1) as Paper EN 37553 ORA
Record Number: 199310881 / Last updated on: 1994-11-29
Original language: en
Available languages: en