采用粒子模拟(PIC)方法模拟了强流电子束在薄磁透镜中的聚焦。建立了强流电子束的聚焦模型，模拟了“神龙一号”加速器某次实验的结果，得到的模拟结果非常接近实验值，证明采用建立的PIC模型模拟强流束经过磁透镜时的聚焦是可信的。应用此模型模拟了电子束参数(入射半径、发射度、能散度、相位角等)对焦斑直径的影响,结果表明：在模拟条件下，电子束平行入射时最佳束包络半径位于20.0~22.5 mm；发射度和能散度对焦斑直径的影响和理论公式吻合得较好；只有入射电子束包络半径和相位角匹配时才能得到小的焦斑直径。

The study uses the particle-in-cell method to simulate the focusing of intense electron beam with the thin magnetic lens. The focusing model of intense electron beam was established and to simulate one experiment on “Dragon-I” accelerator. The simulation result is very close to the experimental one, which proves the validity of the model. The influences of some parameters of electron beam on focusing were simulated. In the simulations, the best envelope diameter of incident paralled beams is 20.0~22.5 mm. For the effects of beam emittance and energy spread, the simulation results agree well with theoretical ones. Moreover, the focal spot of small size can be obtained, only when the envelope diameter and the phase of incident beams are matched.