Wei M S, Mangles S P D, Najmudin Z, Walton B, Gopal A, Tatarakis M, Dangor A E, Clark E L, Evans R G, Fritzler S, Clarke R J, Hernandez-Gomez C, Neely D, Mori W, Tzoufras M, Krushelnick K
Blackett Laboratory, Imperial College, London SW7 2BZ, UK.
Phys Rev Lett. 2004 Oct 8;93(15):155003. doi: 10.1103/PhysRevLett.93.155003. Epub 2004 Oct 7.
Ion acceleration by the interaction of an ultraintense short-pulse laser with an underdense-plasma has been studied at intensities up to 3 x 10(20) W/cm(2). Helium ions having a maximum energy of 13.2+/-1.0 MeV were measured at an angle of 100 degrees from the laser propagation direction. The maximum ion energy scaled with plasma density as n(0.70+/-0.05)(e). Two-dimensional particle-in-cell simulations suggest that multiple collisionless shocks are formed at high density. The interaction of shocks is responsible for the observed plateau structure in the ion spectrum and leads to an enhanced ion acceleration beyond that possible by the ponderomotive potential of the laser alone.
在强度高达3×10²⁰W/cm²的情况下，研究了超强短脉冲激光与低密度等离子体相互作用产生的离子加速。在与激光传播方向成100度角处测量到了最大能量为13.2±1.0 MeV的氦离子。最大离子能量与等离子体密度的标度关系为n(0.70±0.05)(e)。二维粒子模拟表明，在高密度下会形成多个无碰撞激波。激波的相互作用导致了离子谱中观测到的平台结构，并使离子加速增强，超过了仅由激光有质动力势所能实现的加速。
