refractiveindexstructuurparameter
The refractiveindexstructuurparameter, commonly referred to as the refractive index structure parameter and denoted Cn^2, is a statistical quantity that describes the strength of refractive-index fluctuations caused by optical turbulence in a transparent medium. It is most often applied to the Earth's atmosphere, where turbulent air leads to small-scale variations in the refractive index that affect the propagation of light.
Mathematically, the refractive-index structure parameter is linked to the two-point structure function of the refractive index.
Measurement and profiling of Cn^2(z) (the vertical distribution) employ several techniques, including SCIDAR, SLODAR, and DIMM,
Applications of Cn^2 include astronomy (seeing estimation and adaptive optics tuning), laser and free-space optical communication