RF modeling of the ITER-relevant lower hybrid antenna

Abstract

a b s t r a c tIn the frame of the EFDA task HCD-08-03-01, a 5 GHz Lower Hybrid system which should be able to deliver 20 MW CW on ITER and sustain the expected high heat fluxes has been reviewed. The design and overall dimensions of the key RF elements of the launcher and its subsystem has been updated from the 2001 design in collaboration with ITER organization. Modeling of the LH wave propagation and absorption into the plasma shows that the optimal parallel index must be chosen between 1.9 and 2.0 for the ITER steady-state scenario. The present study has been made with n || = 2.0 but can be adapted for n || = 1.9. Individual components have been studied separately giving confidence on the global RF design of the whole antenna.

Benchmark of coupling codes (ALOHA, TOPLHA and GRILL3D) with ITER-relevant Lower Hybrid antenna

“…While referring the interested reader to [5] and [6] for a detailed description of the proposed launcher structures, we briefly introduce here its main geometrical features: the 5 GHz launcher, based on the Passive Active Multi-junction (PAM) concept, consists in 4 identical blocks of 12 rows each. In order to simplify the codes comparison, we limited our analysis to a single row, made up of 24 active waveguides and 25 passive waveguides; the most relevant involved dimensions are listed in Table 1.…”

Contribution to the design of the main transmission line for the ITER relevant LHCD system

“…The resulting doubled number of PAM modules on the same toroidal launcher row increases the flexibility of the whole launcher in term of N || . The complete layout of a PAM module is given in [7].…”

Thermal and mechanical analysis of ITER-relevant LHCD antenna elements

“…It was conducted with a multilinear material model of copper to allow plastic deformations of the skirt. The model used for the design is based on an RF optimized version of the window [7]. Fig.…”

“…The thermal loads have been updated from initial design and thermo-mechanical computations have been carried out for different versions of these components. Simulations were carried out with ANSYS code on the basis of thermal loads obtained with Ansoft HFSS [7].…”