Abstract:
Basic principles are discussed for a first mirrors unit (FMU) design for International Thermonuclear Experimental Reactor (ITER) optical diagnostics, equipped with an RF ...Show MoreMetadata
Abstract:
Basic principles are discussed for a first mirrors unit (FMU) design for International Thermonuclear Experimental Reactor (ITER) optical diagnostics, equipped with an RF capacitive coupled discharge cleaning subsystem. A nontunable RF prematcher device is shown to be desirable in the proximity to the discharge load to avoid excessive heating of an in-vessel RF feeder part. A possibility of satisfactory RF prematching with a simple nontunable L-shaped circuit is demonstrated for the experimentally measured RF discharge impedance variation. The structure of an FMU RF power distribution circuit is suggested, consisting of an RF prematcher, an RF power meter, and, when required, an RF decoupler of a DC-grounded water-cooled mirror. Planar implementation of an RF prematching device is recognized as the most feasible and universal, as a result of analysis of various base element types. Three options of RF-decoupled mirror cooling manifolds are discussed, revealing an optimal selection of their electric and dimensional parameters. A structural implementation of a planar RF prematcher ceramic parts fastening is suggested, taking into account their integrity under inertial, neutron, and thermal loads expected during ITER operation. Successful pilot tests of the RF prematcher performance and structural integrity demonstrate the promise of the described design approach.
Published in: IEEE Transactions on Instrumentation and Measurement ( Volume: 73)