On June 18, the Lower Hybrid Current Drive system (LHCD) — a key subsystem of the Comprehensive Research Facility for Fusion Technology (CRAFT) — successfully passed expert testing and was officially accepted, marking a significant milestone for the project.
Led by the team from the Institute of Plasma Physics under the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, the system has now been fully localized, with all components produced domestically.
As one of the 19 core systems of the facility, the LHCD plays an essential role in advanced fusion research. It is responsible for driving and maintaining the toroidal plasma current in tokamak devices, regulating current distribution, heating plasma electrons, supporting the current ramp-up phase, suppressing edge-localized modes, and optimizing heat flux on the divertor.
The system tackles several key technical challenges, including the design of fusion reactor oriented antenna, long-distance low-loss power transmission, and reliable and safe system operation.
"We have achieved all major technical goals," said Prof. LIU Liang, person in charge of the team, "That includes center frequency of 4.6 GHz, up to 4 megawatts of microwave source power, running stable pulse operations for over 100 seconds, finishing a reactor oriented antenna design, and making real breakthroughs in long-distance low-loss power transmission, mode conversion, and safe, reliable system operation."
Through cooperation with domestic partners, the team developed core components such as 500-kilowatt klystron, 500-kilowatt circulator. These technologies also show great potential for use in other fields, including microwave heating, wireless communication, healthcare, and electronic engineering.
The successful testing and official acceptance of the LHCD system provide a foundation for building advanced heating systems in future fusion reactors.
CRAFT LHCD System (Image by CAI Qimin)
