Characterization of Quasi-Optical Launcher for ECRH in SST-1

The design and characterization of a high-power microwave launcher have been discussed. The launchers have been designed for electron cyclotron resonance heating of the plasma in the SteadyState Superconducting Tokamak (SST-1). High-power microwave beam launchers mainly consist of a focusing mirror and a plane mirror combination to focus the beam at a specified location. Two microwave beam launchers are fabricated to launch the waves from the low magnetic field side (radial port) as well as from the high magnetic field side (top port). The frequency of operation is 82.6 GHz, and the power is 200 kW/continuous wave. A gyrotron capable of delivering 200 kW power at 82.6 GHz is under fabrication at M/s. Gycom. The mirrors of the launchers are based on quasi-optical Gaussian beam theory. The mirrors provide cooling for long-pulse (1000-s) operation. Low-power microwave characterization is done to check the performance of the launchers. A lowpower microwave beam incident on the focusing mirror of the launcher and focusing action is analyzed at the output of the launcher.