Research activities and progress on the long pulse ECRH launcher for EAST

Abstract

A long pulse Electron Cyclotron Resonance Heating (ECRH) system is developed on EAST tokamak for plasma heating and current profile tailoring. The ECRH system is designed to operate at 140GHz and to inject 4MW CW power. With respect to the physical objectives of the newly built ECRH system, a quasi-optical launcher is designed to inject 4MW continuous wave into plasma through an equatorial port. Gaussian beams delivered from evacuated corrugation waveguides will be focused and reflected by high thermal conductive metal mirrors, and then steered by using push-rod steering mechanism with entire scanning range of ±25° toroidally and over 30° poloidally in plasma cross section. The mirrors are carefully designed with mega watts power handling capability and optimum optical characteristics. The performance of steering mechanism has been tested before installation, an open-loop control system for ECRH launcher has been implemented for required mirror movement and proper polarization between plasma discharges. This paper will present the overall design and progress of the launcher, along with the performance in EAST campaigns. Considerations and possible upgrade of the design features relevant to long pulse operation are discussed.

A New Efficient Mirror Cooling for the Transmission Line of Fusion Reactor ECH Systems Based on Triply Periodic Minimal Surfaces

“…In order to prevent the deformation of the mirrors from their ideal shape, they need to be cooled actively through pressurized subcooled water. Typically, the cooling is achieved through cooling channels (following an S-shaped trajectory in the case of the launcher mirrors in EAST [16] and KSTAR [17] or a spiral trajectory in W7-X [18] and in some launcher mirrors for ITER [19], [20], [21], while others rely on serpentine cooling [22], [23]). More recently, new designs have been introduced, as in [24] for instance, where the heat sink is based on cylindrical pins around which the coolant is free to move without any predefined channel, homogenizing the temperature of the mirror.…”