Polarizer Designed for the Electron Cyclotron Resonance Heating System on J-TEXT

An electron cyclotron (EC) resonance heating (ECRH) system with four 60-GHz/200-kW/0.5-s gyrotrons donated by the Culham Science Center is being developed on J-TEXT for plasma heating and magnetohydrodynamics studies. A controlled polarization launcher has been designed to inject the EC beam into plasma with the desired polarization and direction. The polarizer with sinusoidal grooves has been integrated into the launcher for polarization control of the EC wave. We use the coordinate transformation method for the polarizer design. The polarization parameters of the designed polarizer, including the rotation angle and the ellipticity, are measured with a low-power test platform. The experimental results agree well with the numerical calculations, indicating that the designed polarizer can meet the requirements of the ECRH system on J-TEXT.