Impurity release from the ICRF antenna screens in JETFunded under: FP2-FUSION 10C
During the ICRF (Ion Cyclotron Range of Frequencies) heating on JET (Joint European Torus), the highly localised impurity influxes from the Faraday screens (FS) of RF antennae are observed. The influxes result from the acceleration of deuterium and impurity ions in the RF enhanced Bohm-Debye sheaths. The RF enhanced sheaths form when a magnetic field line, linking a large RF magnetic flux, connects two surfaces and closes a loop where the RF voltage is induced. The FS influxes depend on two intimately linked parameters, antenna voltage and the density at FS, as well as on the magnetic field angle, antenna phasing, FS geometry and material. The influx of beryllium (Be) from the front face of the Be-gettered FS is measured and compared for carbon and Be belt limiters.
Bibliographic Reference: Report: JET-P(90)49 EN (1990) 49 pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 199110152 / Last updated on: 1994-12-02
Original language: en
Available languages: en