DESY, Notkestr. 85, 22607 Hamburg, Germany.
Phys Rev Lett. 2010 Mar 26;104(12):125002. doi: 10.1103/PhysRevLett.104.125002. Epub 2010 Mar 25.
We investigate ultrafast (fs) electron dynamics in a liquid hydrogen sample, isochorically and volumetrically heated to a moderately coupled plasma state. Thomson scattering measurements using 91.8 eV photons from the free-electron laser in Hamburg (FLASH at DESY) show that the hydrogen plasma has been driven to a nonthermal state with an electron temperature of 13 eV and an ion temperature below 0.1 eV, while the free-electron density is 2.8x10{20} cm{-3}. For dense plasmas, our experimental data strongly support a nonequilibrium kinetics model that uses impact ionization cross sections based on classical free-electron collisions.
我们研究了在等容加热到中等耦合等离子体状态的液态氢样品中的超快（飞秒）电子动力学。使用来自汉堡自由电子激光（DESY 的 FLASH）的 91.8eV 光子的 Thomson 散射测量表明，氢等离子体已被驱动到具有 13eV 电子温度和低于 0.1eV 的离子温度的非热状态，而自由电子密度为 2.8x10{20}cm{-3}。对于稠密等离子体，我们的实验数据强烈支持使用基于经典自由电子碰撞的碰撞电离截面的非平衡动力学模型。
