用粒子模拟程序研究了长脉冲质子束在等离子体中的传输特性, 模拟结果表明, 等离子体可以明显改善质子束的空间传输特性, 大尺度的等离子体相对于等离子体层可以实现较长距离的稳定传输。研究发现, 在实现长距离传输时, 等离子体波会对质子束密度有较大的调制作用, 严重影响质子束的传输性质, 同时通过优化束密度分布可以有效减弱等离子体波的激发, 实现束较稳定的传输。

Numerical simulations have been conducted on the propagation of a long proton beam in the background plasma with the help of 2D3V PIC code. The simulations show that the plasma improves the propagation of the proton beam obviously. And for long distance propagation, the proton beam has a more stationary profile when propagating in the bulk plasma compared to propagating in the plasma slab. The plasma wave excited by the beam can modulate the density of the proton beam, influencing the beam’s stable propagation, and the results of the simulations confirm that the proton beam with a smooth edge-density profile can minimize the excitation of plasma waves.