Hybrid结构的周期永磁聚束系统的研究

Research of Hybrid Periodic Permanent Magnet Focusing System

设计了Hybrid结构的周期永磁聚束系统,该结构不仅轴向磁感应强度很高,而且体系外的漏磁很弱。内径为15mm,外径为40 mm,周期为40 mm,径向磁环和轴向磁环厚度之比为1∶1的Hybrid-PPM结构,轴线上磁感应强度的峰值达到0.5 T,体系外漏磁小于0.06 T。对影响Hybrid结构的PPM磁场峰值分布的因素进行了分析,磁场分布的峰值随内径增大迅速下降;外径增大对峰值的影响不显著,当外径增加至与体系的周期相当时,峰值几乎不变;体系的峰值随周期长度的增加迅速增大;体系的峰值与周期内径向磁环与轴向磁环厚度的比值有关,周期一定时,存在一个最佳的比值点,磁场的峰值达到最大。

A hybrid periodic permanent magnet has been designed, which have high axial magnetic field in axle and low magnetic leakage out of the structure. In the hybrid PPM with 15 mm in inside radius, 40 mm in outside radius, 40 mm in periodic length, and 1 ： 1 in the ratio of the length of radially magnetized ring to that of the axially magnetized ring, the peak axial field in axle can reach to 0.5 T, and the field out of the structure can be less than 0.06 T. The factors which can influence the magnetic field of hybrid PPM have been studied. The peak field decreases as inside radius increases, but increasing outside radius has little effect on the peak field, especially when the outside radius is comparable with periodic length of the system, the peak field almost does not change. The peak field increases rapidly as the periodic length increases. The peak field has something to do with the ratio of the length of radially magnetized ring to that of the axially magnetized ring. When the periodic length if fixed, there is an optimum ratio, at which the peak field reaches to maximum.