AbstractA mock-up module of an antenna tip made of carbon fiber composite (CFC) was fabricated for the development of a heat-resistive front of the lower hybrid current drive (LHCD) antenna. The CFC surface was coated with a thin Ti layer and was plated with Cu. The mock-up module has three waveguides and is designed to simulate the front tip of the 8 GHz LHCD antenna. The module has an active water cooling channel and the length is 200 mm, the mouth dimension is 19.5×50 mm2. The mock-up module was tested with heat fluxes up to 20 MW m−2 due to electron beam irradiation. No damage of the waveguide mouth was observed up to the heat flux of 3.2 MW m−2 for 2 min, though a maximum temperature of 762°C was measured at the septum plate. The obtained heat load of 3.2 MW m−2 is about 10 times higher than the steady-state surface-averaged heat load of the first wall required in the ITER design.
Development of an arch antenna for LHCD in a spherical tokamak