Observation of Ultrafast Nonequilibrium Collective Dynamics in Warm Dense Hydrogen
Observation of Ultrafast Nonequilibrium Collective Dynamics in Warm Dense Hydrogen
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DOI：
10.1103/physrevlett.104.125002
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发表时间：
2010-03-26
影响因子：
8.6
通讯作者：
Tschentscher, Th.
中科院分区：
文献类型：
--
作者：
Faeustlin, R. R.;Bornath, Th.;Tschentscher, Th.
我们研究了液氢样品的超快（fs）电子动力学，等长和体积加热到中等耦合等离子体状态。利用来自汉堡自由电子激光器的91.8 eV光子（DESY FLASH）进行的汤姆森散射测量表明，氢等离子体已被驱动到电子温度为13 eV、离子温度低于0.1 eV的非热态，而自由电子密度为2:8 × 10(20) cm（-3）。对于致密等离子体，我们的实验数据强烈支持非平衡动力学模型，该模型使用基于经典自由电子碰撞的冲击电离截面。
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: 8 x 10(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.