METAL SOURCES AND GENERAL IMPURITY BEHAVIOUR IN JET PLASMAS DURING ICRH
The Faraday screens of the RF antennae have been identified as the original sources of metal impurities during ICRH in JET. Migration of metal impurities from the antennae screens to the limiters and protection tiles has been observed, leading to a build-up of metal concentrations in ohmic plasmas and aggravating the increase during RF. It has been observed that the limiters and protection tiles are cleaned by operation without RF within a few pulses. Carbonization leads to a temporary reduction of metals before and during RF heating. In all cases, radiated power and Z-eff of the plasma are dominated by contributions from light impurities (C,O), and metals only contribute some 20% to P-rad.
Bibliographic Reference: 13TH EUROPEAN CONFERENCE ON CONTROLLED FUSION AND PLASMA HEATING, SCHLIERSEE (GERMANY), APRIL 14-18, 1986 PP. 101-104 WRITE TO THE PUBLICATIONS OFFICER, JET JOINT UNDERTAKING, ABINGDON, OXON, OX14 3EA (UK) MENTIONING REPORT JET-P(86)15, 1986
Record Number: 1989125006000 / Last updated on: 1987-01-01
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