原题.幻日是一种非常罕见的光学现象(如图1甲为2012年12月10日,上海出现的“三个太阳”即幻日现象).在天空出现的半透明薄云里面,有许多飘浮在空中的六角形柱状的冰晶体,偶尔它们会整整齐齐地垂直排列在空中.当太阳光射在这一根根六角形冰柱上,就会发生非常规律的折射现象(如图1乙).有人在实验室用白光束和转动的六角棱镜模拟了幻日现象(如图1丙). The original title. Magic day is a very rare optical phenomenon (Figure 1 A is December 10, 2012, Shanghai appeared “three sun ” or illusion phenomenon.) In the sky appeared translucent thin cloud Inside, there are many hexagonal columnar ice crystals that float in the air, and occasionally they are neatly aligned vertically in the air.When sunlight impinges on this rooted hexagonal icicle, very regular refraction occurs (Figure 1 B) Some people in the laboratory with a white light beam and rotating hexagonal prism simulated illusion (Figure 1 C).