Fig. 1. Electric and magnetic fields distribution in the cathode vicinity

Fig. 2. Transverse distribution at z = 0.0 m and z =2.0 m

Fig. 3. Resolution versus solenoid magnetic field 分辨率 随螺线管磁场的变化

Fig. 4. with different radius (R is the maximum radius of the initial particle distribution) 不同半径情况下的 (图中R为初始束团分布的最大半径)

Fig. 5. Transverse momentum distribution and particle distribution at z=2.0 m

Fig. 6. as a function of the bucking solenoid current , when =200 A 束斑尺寸 随副线圈电流 的变化， =200 A时阴极表面磁场为零