Tunable biasing magnetic field design of ferrite tuner for ICRF heating system in EAST

• Published in: Plasma science & technology Vol. 19; no. 11; pp. 82 - 91
• Main Author: 徐曼曼;宋云涛;陈根;赵燕平;毛玉周;刘广;彭振
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.11.2017
• Subjects: biasing magnet; EAST; ferrite tuner; ICRF; ICRF heating; 交变磁场; 加热系统; 可调偏置; 等离子体参数; 设计目标; 调谐器; 铁氧体材料
• ISSN: 1009-0630; 1009-0630
• DOI: 10.1088/2058-6272/aa8167

Ion cyclotron range of frequency（ICRF） heating has been used in tokamaks as one of the most successful auxiliary heating tools and has been adopted in the EAST. However, the antenna load will fluctuate with the change of plasma parameters in the ICRF heating process. To ensure the steady operation of the ICRF heating system in the EAST, fast ferrite tuner（FFT） has been carried out to achieve real-time impedance matching. For the requirements of the FFT impedance matching system, the magnet system of the ferrite tuner（FT） was designed by numerical simulations and experimental analysis, where the biasing magnetic circuit and alternating magnetic circuit were the key researched parts of the ferrite magnet. The integral design goal of the FT magnetic circuit is that DC bias magnetic field is 2000 Gs and alternating magnetic field is±400 Gs. In the FTT, E-type magnetic circuit was adopted. Ferrite material is Nd Fe B with a thickness of 30 mm by setting the working point of Nd Fe B, and the ampere turn of excitation coil is 25 through the theoretical calculation and simulation analysis. The coil inductance to generate alternating magnetic field is about 7 m H. Eddy-current effect has been analyzed, while the magnetic field distribution has been measured by a Hall probe in the medium plane of the biasing magnet. Finally, the test results show the good performance of the biasing magnet satisfying the design and operating requirements of the FFT.