Coupling of slow waves near the lower hybrid frequency in JET : implications for the launcher designFunded under: FP1-FUSION 9C
The physical and coupling properties of the JET lower hybrid antenna have been investigated numerically with a 2-D computer code based on the linear coupling theory. The antenna utilises an array of multijunction units and their "self-adaptation" property is analysed. The geometrical parameters of the multijunction unit have been properly optimised (choice of the location of the E-plane junctions, wall thickness) and their values have been taken into account in the launcher manufacture. With such an optimisation, power reflection coefficient below 1.5% and directivity (based on the current drive efficiency) between 60% and 70% are expected at the optimum plasma density (n(e) approx. 1.0 E18 /m3). Edge effects are minimised using two shorted passive wave-guides on each side of the antenna. Finally the accessibility limit on the coupling is investigated.
Bibliographic Reference: Report: JET-R(89)02 EN (1989)
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 198910752 / Last updated on: 1994-12-01
Original language: en
Available languages: en