论文标题
在等离子体中长期质子束的绝热聚焦
Adiabatic Focusing of a Long Proton Bunch in Plasma
论文作者
论文摘要
我们在实验中表明，长血浆绝热响应集中了一个长长的相对论质子束。游离的等离子体电子迁移以中和束的空间电荷场，因此，束由其自身电流产生的方位角磁场聚焦，而径向电场无法平衡。由于束的长度比等离子电子波长长得多，因此束也经历了自调节不稳定性。因此，韦克菲尔德的幅度沿着束和等离子体生长，自我调制的散焦效应在绝热聚焦效果上可能占主导地位。我们表明，当用前面的电子束播种自调制时，绝热响应的效果与自调调制的效果之间的过渡取决于种子韦克菲尔德的幅度。
We show in experiments that a long, relativistic proton bunch is focused by the plasma adiabatic response. The free plasma electrons migrate so as to neutralize the space charge field of the bunch, and the bunch is therefore focused by the azimuthal magnetic field generated by its own current, that is not balanced by the radial electric field. Since the length of the bunch is much longer than the plasma electron wavelength, the bunch also undergoes the self-modulation instability. Thus, the amplitude of the wakefields grows along the bunch and along the plasma, and the defocusing effect of the self-modulation can become dominant over the adiabatic focusing effect. We show that, when seeding the self-modulation with a preceding electron bunch, the transition between the effect of the adiabatic response and that of the self-modulation depends on the amplitude of the seed wakefields.
