周期凸起磁场聚焦带状电子注的3维粒子模拟

 从麦克斯韦方程出发，分析了带状电子注在螺线管磁场中传输时Diocotron模形成的原因；对周期凸起磁场(PCM)聚焦下的电子受力进行分析，分析表明PCM磁场能够抑制Diocotron模。结合理论分析，利用3维粒子模拟程序， 对Diocotron模的形成进行了研究，并利用了PCM磁场聚焦带状电子注，抑制Diocotron模。通过粒子模拟研究了磁场大小对PCM磁场抑制Diocotron模的影响，结果表明：磁场减少导致空间电荷力和磁力需要平衡，其侧面包络变厚。

3D simulation of periodic cusped magnetic focusing sheet electron beam

When the sheet electron beam is transmitting in solenoid magnetic fields,Diocotron mode or Diocotron instability comes into being,which could lead to collapse of beam propagation.In this paper,Diocotron mode theory is derived from Maxwell equations.Forces on electrons is analyzed in periodic cusped magnetic(PCM) focusing,and the result shows PCM can restrain Diocotron mode.Using 3D PIC program,formation of Diocotron mode is analyzed,and PCM focusing sheet electron beam and restraining Diocotron mode are simulated.The effect of Diocotron mode in sheet electron beam is also studied with changed PCM magnitude.The results show that space charge force and magnetic force need rebalance,which leads profile of beam to be thicken,when PCM magnitude is reduced.