Implementation of partial frequency redistribution effects for chromospheric resonance spectral lines in 3D model atmospheres

We implemented effects of non-coherent frequency scattering known as partial redistribution (PRD) in our radiative transfer code Multi3D to treat properly the formation of resonance spectral lines like Mg II k&h, Ca II K&H, H I Lyman_α etc. Profile intensities of these lines are formed under PRD mostly in the chromosphere. They are widely accepted diagnostic tools for studying the upper solar atmosphere, where effects of photon scattering become important. We employed the hybrid approximation for the angle-dependent case of the R_{rm II} redistribution function as suggested by Leenaarts et al. (2012) to save both computational time and memory usage. We also performed an additional effective management of memory and time by properly choosing frequency quadrature points and by optimizing an algorithm for the mean intensity and the absorption profile interpolation. We compared profiles computed by our code with the profiles produced by the RH code (Uitenbroek 2001, Pereira & Uitenbroek 2015) using a standard 1D model atmosphere FAL-C for which we found a perfect agreement. Here we also present our recent modeling using a 3D~Bifrost model atmosphere. We discuss possible consequences resulting from the interpretation of observed PRD lines based on a simplifying approximation of complete frequency redistribution (CRD) as has been customary in observational solar physics before.