倾斜因子

斯托克斯用惠更斯原理推導的，用來表示一個波的主要能量向前移動、阻止向後傳播的因子:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle cos{\frac{\phi}{2}} \approx \frac{1+cos{\phi}}{2} } ,

式中，Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): \phi 表示再次輻射的方向和到達方向的角度。