Effect of wall corrugations on the lower hybrid wave spectrum of a waveguide array

The effect of wall corrugations on the lower hybrid wave spectrum of a waveguide array is investigated in a linear approach for the conditions of the Alcator A experiment. It was found that a limited number of grooves placed on both sides of a two-waveguide grill can considerably alter the wave power spectrum launched into the plasma. However, if the set of the grooves is situated further than one wavelength from the grill its influence on the wave power spectrum is weak.