# A 3D radiative transfer framework: VI. PHOENIX/3D example applications

## TL;DR

This paper demonstrates the application of a 3D radiative transfer framework within the PHOENIX/3D code, showcasing its scalability and accuracy across diverse atmospheric conditions for spectrum synthesis.

## Contribution

It introduces an extended 3D version of PHOENIX, integrating the 3DRT framework, and validates its performance and accuracy against 1D models using various test cases.

## Key findings

- 3D radiative transfer calculations are feasible with current computational resources.
- The 3D models show good agreement with 1D models in test cases.
- The framework scales well with parallel computing.

## Abstract

We demonstrate the application of our 3D radiative transfer framework in the model atmosphere code PHOENIX/3D for a number of spectrum synthesis calculations for very different conditions. The 3DRT framework discussed in the previous papers of this series was added to our general-purpose model atmosphere code PHOENIX/1D and an extended 3D version PHOENIX/3D was created. The \phxT code is parallelized via the MPI library using a hierarchical domain decomposition and displays very good strong scaling. We present the results of several test cases for widely different atmosphere conditions and compare the 3D calculations with equivalent 1D models to assess the internal accuracy of the 3D modeling. In addition, we show the results for a number of parameterized 3D structures. With presently available computational resources it is possible to solve the full 3D radiative transfer (including scattering) problem with the same micro-physics as included in 1D modeling.