In order to assist the design of the future ITER Lower Hybrid launcher, coupling codes
ALOHA, from CEA Cadarache, TOPLHA, from Politecnico di Torino, and GRILL3D
(Dr.Mikhail Irzak, A.F.Ioffe Physico-Technical Institute, St. Petersburg, Russia), from ENEA
Frascati, have been compared with the initial (3 modules with 8 active waveguides per
module) and updated (6 modules with 4 active waveguides per module) Passive-Active Multijunction
(PAM) Lower Hybrid antennas. Both ALOHA and GRILL3D formulate the problem
in terms of rectangular waveguides modes, while TOPLHA is based on boundary-value
problem with the adoption of a triangular cell-mesh to represent the relevant waveguides
surfaces.
Several plasma profiles, with varying edge density and density increase, have been adopted to
provide a complete description of the simulated launcher in terms of reflection coefficient,
computed at the beginning of each LH module, and of power spectra. Good agreement can be
observed among codes for all the simulated profiles