A Lower Hybrid Current Drive System for Alcator C-Mod
Authors: S. Bernabei, J.C. Hosea, D. Loesser, J. Rushinski, J.R. Wilson, P. Bonoli, M. Grimes, R. Parker, M. Porkolab, D. Terry, and P. Woskov
Date of PPPL Report: May 2001
To be presented at: the 14th Topical Conference on Applications of Radio Frequency Powers in Plasmas to be held in Oxnard, CA, May 7-9, 2001. Proceedings to be published by the American Institute of Physics (AIP).
A Lower Hybrid Current Drive system is being constructed jointly by Plasma Science and Fusion Center (PSFC) and Princeton Plasma Physics Laboratroy (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 Lower Hybrid (LH) system consists of 3 MW power at 4.6 GHz with a maximum pulse length of 5 seconds. Twelve 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 solution which will be presented.