Lower Hybrid Current Drive System for Alcator C-Mod

摘要

A Lower Hybrid Current Drive system is being constructed jointly by PSFC and PPPL for installation on the Alcator C-Mod tokamak, with the primary goal of driving plasma current in the outer region of the plasma. The LH system consists of 3 MW power at 4.6 GHz with a maximum pulse length of 5 seconds. 12 Klystrons will feed an array of 4-vertical and 24- horizontal waveguides mounted in one equatorial port. The coupler will incorporate some compact characteristics of the multijunction power splitting while retaining full control of the toroidal phase. In addition a dynamic phase control system will allow feedback stabilization of MHD modes. The desire to avoid possible waveguide breakdown and the need for compactness have resulted in some innovative technical solutions, which will be presented.