基于预群聚的回旋管注入锁相研究

Study on injection locked gyrotron with pre-bunched beam

开展了40kW预群聚注入锁相回旋管的理论与模拟设计。基于全电磁仿真方法完成了预群聚腔的设计,并采用给定场理论对电子束经过预调制腔后的群聚状态进行了计算。采用自洽理论获得了回旋管的自由振荡工作参数,并计算了振荡频率随各种参数变化的规律,由此提出了锁相带宽的要求。采用PIC粒子模拟进行了锁相状态的模拟,得到7mm漂移距离下锁定增益可达30.5dB,相应的锁相带宽为20MHz。如果进一步增长漂移距离或者进一步增大输入功率,锁相带宽还会增大。理论计算和粒子模拟结果表明40kW级回旋管注入锁相具有良好的可行性。

A 40 kW injection locked gyrotron is designed based on theoretical calculations and simulations.The interaction structure is formed by two cavities which operate under TE01-TE03 mode pair.The state of the beam across the pre-bunching cavity is calculated with the fixed profile theory,and the operation parameters of the gyrotron under free oscillation state is calculated with the self-consistent theory.The regulation of the oscillation frequency varying with the parameters is achieved,based on which the locking bandwidth is proposed.A PIC code is used for simulating the injection locking state,again of 30.5 dB and a locking bandwidth of 20 MHz are achieved under a drifting length of 7 mm.If the drifting length or the input power is increased,the locking bandwidth could be wider.The calculations and simulations show that injection locking of the 40 kW gyrotron is feasible.