双阳极磁控注入枪设计参数对其性能的影响分析

 对34GHz基波回旋管双阳极磁控注入枪的优化做了详细的研究和计算，数值模拟了阳极电压、注电流、枪体尺寸加工误差、外加直流磁场等因素对电子枪的影响。模拟结果表明：增大阳极电压不但可以提高速度比，而且可以降低横向速度零散。磁场压缩比减小，使电子注具有最小速度零散的电流值增大；同时，电子注的速度比降低，最小横向速度零散值也增大。必须慎重选择阳极形状，以提高电子枪的性能并保证电子注的稳定性；同时，还发现由于阳极结构的变化导致阴极电场分布的变化，使电子注的注电流在各因子变化过程中出现了微小的扰动。减小Bc可以增大电子注的速度比，还可以减小电子注的横向速度零散，但是当电子注的速度比增大到一定值时，电子注的性能就会变得不太稳定。

Influence of the design parameters of magnetic injection gun on it's performance

Particular simulations on the 34GHz Gyrotrons magnetic injection gun(MIG) consider the influences of such design parameters as: control anode voltage, beam current, structure of MIG and external dc magnetic field. The results show that when control anode voltage increases or magnetic induction intension near cathode decreases, beam velocity ratio will increase while beam velocity spread decreases; as known, beam motion in the gun is affected by the interaction of magnetic field and space charge force, when beam current changes, the minimal velocity spread will gain at a best current; when the magnetic field compression ratio changes lower, the best current value will raise, and beam velocity ratio decrease, meanwhile minimal velocity spread will be a new higher value. The structure of the MIGmust be carefully selected, as the tiny change on it will affect beam performance highly, and beam current will fluctuate punily. It must be noted that beam ratio should be maintained in a proper range, otherwise beam stability will be worse.