Lower hybrid current drive (LHCD) system is one of the important tools to sustain long pulse discharge and improve plasma confinement in tokamak device. There are two LHCD systems working at CW mode with the parameters of 4MW/2.45GHz and 6MW/4.6GHz, respectively. One with 2.45GHz frequency is located at B (N before 2021) port and another one with 4.6 GHz is at E port. Each system consists of microwave source, transmission line, multi-junction antenna, high voltage power supply, control system, water cooling system, and so on. At present, the highest injection power of the two systems during the plasma experiments is 2.8MW and 3.7MW, respectively. The main purpose of the two systems is to maintain steady-state plasma, control the plasma current profile, and to realize high confinement plasma operation. A long pulse operation of 411s plasma has been realized by the 2.45GHz LHCD system, and a world record of high performance plasma with 101.2s has been achieved by the synergy of the two LHCD systems and ECRH system in EAST.

Fig.1.  Layout of the 4.6 GHz LHCD system in EAST