Controllability Study of Propagating Mode Content by an Angle-Adjustable Mirror of a Miter-Bend in EC H&CD Transmission Line

A miter-bend-type mode converter, which has an angle-adjustable mirror, is proposed to control the transmission mode content in the electron cyclotron heating and current drive transmission line. This component excites the higher order mode by injecting a tilted radio frequency beam into a waveguide using the angle-adjustable mirror. A mock-up model of the converter was developed to evaluate the principle of the mode conversion. The experimental result of the mock-up representing the ratio of LP01 mode and LP11 mode was successfully controlled by 10% as the theoretical prediction.