Measurement of fluctuations in cooled plasma using a microscopic laser-induced fluorescence method

离子阱是研究等离子体中粒子间相关效应的合适装置，因为使用激光冷却方法可以在良好控制的条件下产生气相、液相和固相等离子体。由于相关效应被认为是频谱形状的微小变化，因此提高诊断的准确性以发现它是很重要的。在这项研究中，我们开发了一种显微激光诱导荧光（LIF）系统，用于诊断微小的单组分激光冷却等离子体。此外，我们还改进了激光系统的调谐范围和稳定性，以实现更宽的离子温度范围和更好的等离子体稳定性。我们对光谱形状的变化进行了详细的研究，发现了中等耦合等离子体中库仑屏蔽机制的变化。

An ion trap is a suitable device for the study of the effect of inter-particle correlation in a plasma, since the gas, liquid, and solid phase plasmas are able to be generated under well-controlled condition using the laser cooling method. Since the correlation effect is thought to appear as small modification of the spectrum shape, it is important to improve the accuracy of the diagnostics to find it. In this study, we developed a microscopic laser induced fluorescence (LIF) system for the diagnostics of a tiny one-component laser-cooled plasma. In addition, we improved the tuning range and stability of the laser systems in order to achieve wider range of ion temperature and better stability of the plasma. We performed the detailed study of the change of the spectrum shape, and found the change of Coulomb screening mechanism in the moderately-coupled plasma.