论文标题
在扩展的超低等离子体中的超快电子冷却
Ultrafast Electron Cooling in an Expanding Ultracold Plasma
论文作者
论文摘要
等离子体动力学在很大程度上取决于密度和温度，因此良好控制的实验实现是理论模型的必不可少的基准。可以通过单个飞秒激光脉冲将可调节数量的原子电离在微米尺寸的Bose-Einenstein冷凝物（BEC）中电离来触发超速血浆的形成。较大的密度与BEC极低的温度相结合，在迄今未探索的尚未探索的超低中性等离子体和电离纳米群中引起了最初强烈耦合的血浆。在这里，我们报告了电子对电子的超快冷却，该冷却被困在密集离子核的远程库仑电势中，冷却速率为400 k/ps。此外，我们的实验设置可以直接进入电子温度，该电子温度在小于500 ns的情况下从5250 K到低于10 k的电子温度。
Plasma dynamics critically depends on density and temperature, thus well-controlled experimental realizations are essential benchmarks for theoretical models. The formation of an ultracold plasma can be triggered by ionizing a tunable number of atoms in a micrometer-sized volume of a Bose-Einstein condensate (BEC) by a single femtosecond laser pulse. The large density combined with the extremely low temperature of the BEC give rise to an initially strongly coupled plasma in a so far unexplored regime bridging ultracold neutral plasma and ionized nanoclusters. Here, we report on ultrafast cooling of electrons, trapped on orbital trajectories in the long-range Coulomb potential of the dense ionic core, with a cooling rate of 400 K/ps. Furthermore, our experimental setup grants direct access to the electron temperature that relaxes from 5250 K to below 10 K in less than 500 ns.
