Institut für Theoretische Physik I, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany.
Phys Rev Lett. 2010 Aug 6;105(6):065002. doi: 10.1103/PhysRevLett.105.065002. Epub 2010 Aug 4.
By using multidimensional particle-in-cell simulations, we present a new regime of stable proton beam acceleration which takes place when a two-ion-species shaped foil is illuminated by a circularly polarized laser pulse. In the simulations, the lighter protons are nearly instantaneously separated from the heavier carbon ions due to the charge-to-mass ratio difference. The heavy ion layer expands in space and acts to buffer the proton layer from the Rayleigh-Taylor-like (RT) instability that would have otherwise degraded the proton beam acceleration. A simple three-interface model is formulated to explain qualitatively the stable acceleration of the light ions. In the absence of the RT instability, the high quality monoenergetic proton bunch persists even after the laser-foil interaction ends.
利用多维的粒子模拟，我们展示了一种新的稳定质子束加速模式，当一个具有两种离子物种形状的箔片被圆形偏振激光脉冲照射时，就会出现这种模式。在模拟中，由于电荷与质量的比值差异，较轻的质子几乎瞬间与较重的碳离子分离。重离子层在空间中扩展，充当质子层的缓冲，以防止瑞利-泰勒型（RT）不稳定性，否则会降低质子束的加速。一个简单的三界面模型被提出，定性地解释了轻离子的稳定加速。在没有 RT 不稳定性的情况下，即使在激光箔片相互作用结束后，高质量的单能质子束也会持续存在。
