海市蜃楼形成的理论分析与实验模拟再现

Theoretical analysis and experimental reconstruction of the mirage phenomenon

分别根据费马原理和光学拉格朗日方程进行了理论推导,得到了自然界里出现的上现蜃景海市蜃楼现象,光线在大气中传输的轨迹方程.两种方法得到的方程所描绘的都是一系列向上凸的曲线,以利用分层折射率的分析方法得到的曲线相似,解释了上现蜃景海市蜃楼的形成原因.利用浓液法对海市蜃楼中的上现蜃景进行了实验模拟再现.实验过程中采用了“纱网框上浮法”注入清水,成功配制了折射率随高度均匀梯度变化的NaCl水溶液,穿过浓液的激光光路和理论轨迹方程曲线相似,观察到了实景物清晰稳定的上现蜃景像.

Utilizing the theoretical derivation based on Fermat principle and optical Lagrange equation, the trajectory equation of the light transmitting in atmosphere was obtained, and the natural upper mirage phenomenon was studied. The equations describe a series of convex curves, like the curves obtained by the layered refractive index method. Furthermore, the upper mirage phenomenon was experimentally simulated by using the solution method. By injecting pure water into the solution using a new “floating gauze net” approach, the NaCl solution with uniform vertical refractive index gradient was prepared. In addition, the laser path through the concentrated liquid was similar to the theoretical trajectory equation curve, the stable upper mirage of the object was observed.