GoLP/Instituto de Plasmas e Fusão Nuclear-Laboratório Associado, Instituto Superior Técnico, 1049-001 Lisboa, Portugal.
Phys Rev Lett. 2012 Nov 21;109(21):215001. doi: 10.1103/PhysRevLett.109.215001. Epub 2012 Nov 20.
We show that monoenergetic ion beams can be accelerated by moderate Mach number collisionless, electrostatic shocks propagating in a long scale-length exponentially decaying plasma profile. Strong plasma heating and density steepening produced by an intense laser pulse near the critical density can launch such shocks that propagate in the extended plasma at high velocities. The generation of a monoenergetic ion beam is possible due to the small and constant sheath electric field associated with the slowly decreasing density profile. The conditions for the acceleration of high-quality, energetic ion beams are identified through theory and multidimensional particle-in-cell simulations. The scaling of the ion energy with laser intensity shows that it is possible to generate ~200 MeV proton beams with state-of-the-art 100 TW class laser systems.
我们表明，单能离子束可以通过在长尺度长度上传播的中等马赫数无碰撞静电激波来加速，该激波在指数衰减等离子体轮廓中传播。在临界密度附近的强激光脉冲产生的强烈等离子体加热和密度陡化可以产生这种在高速下在扩展等离子体中传播的激波。由于与密度缓慢减小的轮廓相关的小而恒定的鞘电场，产生单能离子束成为可能。通过理论和多维粒子模拟确定了加速高质量、高能离子束的条件。随着激光强度的增加，离子能量的变化表明，使用最先进的 100 TW 级激光系统可以产生约 200 MeV 的质子束。
