If I correctly got the question, then the existence of refractive index can be described by the process that is a scattering of some kind. Really, electric field of light wave polarizes atoms or molecules forming oscillating dipoles. These dipoles emit (SCATTER) the light at the same frequency, and emitted light interferes with external one. Result of interference is the wave with the wavelength shorter that external one outside the medium. This is interpreted as existence of refractive index n>1. Details are omitted for the sake of simplicity

Absolutely agree with Aleksandr Aleksandrovsky. The scattering depends on the refractive index not vice versa. Imagine that you have particles with refractive index np embedded in a matrix with refractive index nm. The scattering intensity depends on the size and refractive index contrast between particles and matrix (np-nm). For the same particle size the scattering will be strongest for higher (np-nm)

scattering of light depend on refractive index but reverse is not true as refractive index is a relative quantity.    If:

Particles size< wavelength of light=scattering or tunneling

particle size=wavelength then diffraction of light

particle size>wavelength then either blocked or transfer of energy

refractive index mainly recess the speed of light unevenly which causes the interference of light waves and hence scattering starts...

How you understand "in simple terms" the process described in the section 22.13 in the book:

F.A. Jenkins and H.E. White, “Fundamentals of Optics”, 4th Ed.,MacGraw-Hill Inc.(1981)

Thank you in advance!

Aleksandr Aleksandrovsky view has much meaning

https://physics.stackexchange.com/questions/143438/dependence-of-scattering-on-particle-size-and-refractive-index

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Vladimir Farber In simple terms, your book section seems to say:

If you have randomly moving smoke particles the total scattering is related to the (incoherent) addition of the individual scattering intensity contributions. But in the case of a homogenous material, the individual contributions are added coherently as their fields, not their intensities. A consequence of the mathematics is that the combination of the field leads to a phase change related to the polarizability. This phase change can however also be described as happening due to the refractive index in a 'slice of material'. So the refractive index and polarizability are related, and the typical conceptualization is that scattering depends on polarizability.