Simien C E, Chen Y C, Gupta P, Laha S, Martinez Y N, Mickelson P G, Nagel S B, Killian T C
Department of Physics and Astronomy and Rice Quantum Institute, Rice University, Houston, Texas 77251, USA.
Phys Rev Lett. 2004 Apr 9;92(14):143001. doi: 10.1103/PhysRevLett.92.143001. Epub 2004 Apr 6.
We report optical absorption imaging of ultracold neutral strontium plasmas. The ion absorption spectrum determined from the images is Doppler broadened and thus provides a quantitative measure of the ion kinetic energy. For the particular plasma conditions studied, ions heat rapidly as they equilibrate during the first 250 ns after plasma formation. Equilibration leaves ions on the border between the weakly coupled gaseous and strongly coupled liquid states. On a longer time scale of microseconds, pressure exerted by the trapped electron gas accelerates the ions radially.
我们报告了超冷中性锶等离子体的光吸收成像。从图像确定的离子吸收光谱存在多普勒展宽，因此提供了离子动能的定量测量。对于所研究的特定等离子体条件，离子在等离子体形成后的最初250纳秒内达到平衡时会迅速升温。平衡使离子处于弱耦合气态和强耦合液态之间的边界。在微秒级的较长时间尺度上，捕获的电子气施加的压力会使离子沿径向加速。
