A diffusion model for light scattering in ejecta

TL;DR

This paper introduces a diffusion model for light scattering in ejecta from shock experiments, simplifying analysis of spectrograms in complex scattering regimes, and assesses its validity against traditional radiative transfer models.

Contribution

It presents a novel diffusion equation for ejecta light scattering, offering a simpler alternative to the Radiative Transfer Equation and analyzing its applicability limits.

Findings

The diffusion model effectively describes light scattering in multiple scattering regimes.

The model's validity is confirmed within specific ejecta property ranges.

Comparison shows the diffusion approach simplifies analysis without significant accuracy loss.

Abstract

We derive a diffusion equation for light scattering from ejecta produced by extreme shocks on metallic samples. This model is easier to handle than a more conventional model based on the Radiative Transfer Equation (RTE), and is a relevant tool to analyze spectrograms obtained from Photon Doppler Velocimetry (PDV) measurements in the deep multiple scattering regime. We also determine the limits of validity of the diffusive model compared to the RTE, based on a detailed analysis of various ejecta properties in configurations with increasing complexity.