jaxrts: A Python package for simulating X-ray Thomson scattering spectra from dense plasmas using jax

Over the last decades, X-ray Thomson scattering has become a valuable experimental technique to study dense plasma and warm dense matter states. Designing experiments and interpreting data typically requires the simulation of spectra for given sets of plasma parameters. Many models applicable to different conditions have been formulated by the community. However, an open, broadly available code combining these efforts has been lacking. In this work, we introduce the open-source simulation package jaxrts , a Python implementation incorporating several models, designed to be modular, extensible, transparent, and user-friendly. The software unites Python’s flexibility with computational efficiency through jax ’s just-in-time compilation and GPU acceleration. Program Title: jaxrts CPC Library link to program files: https://doi.org/10.17632/2447gtmdyy.1 Developer’s repository link: https://github.com/jaxrts/jaxrts Licensing provisions: BSD 3-clause Programming language: Python Nature of problem: Dense plasma conditions are routinely created in high-energy-density physics studies, where they are produced, e.g., by X-ray free-electron or high-power optical lasers. To investigate the extreme states generated, X-ray Thomson scattering is a well-established key diagnostic. Interpreting such experiments often requires calculating synthetic spectra. Yet, no unified, openly available computational framework exists to date. Current models are distributed across specialized or proprietary codes, limiting reproducibility, consistency, and systematic comparison. Solution method: The jaxrts package provides an open-source, Python-based framework for simulating X-ray Thomson scattering spectra. It integrates existing theoretical models within a modular package, allowing users to compare and apply different approaches. Implemented with jax , the code benefits from just-in-time compilation and optional GPU acceleration to improve computational performance without sacrificing readability or flexibility. Designed for transparency and ease of extension, jaxrts enables researchers to adapt or expand its functionality for specific applications across a range of plasma conditions.