acherus 0.8.0

3D spatiotemporal solver, focused in atmospheric laser-plasma filaments

Open-source laser pulse filamentation solver

🚀 HASTUR Project - Harnessing Atmospheric Lasing: Towards Ultrasensitive Detection of Toxic Agents and Pathogens

🏢 ETSII-UPM. Instituto de Fusión Nuclear Guillermo Velarde

About

Acherus is a 3D spatiotemporal filamentation code that solves the nonlinear envelope equation (NEE) for ultrashort and ultraintense cylindrically symmetric laser pulses propagating through optically transparent media using various numerical schemes. It computes the laser pulse intensity and fluence distribution, as well as its radius, together with the generated plasma electron density. It is capable of reproducing both numerical and experimental results in different scenarios, allowing the simulation of condensed dielectric, liquid, and gaseous media.

For example, atmospheric filamentation can be studied thanks to the interaction of laser pulses with nitrogen and oxygen diatomic molecules. Another common medium where filamentation has been reported experimentally is water (or in any other aqueous media), as well as dense dielectrics like fused silica, since this phenomenon was first discovered by M. Hercher (1964) (see p. 280) when laser-induced damage tracks were found in glass during an experiment.

How to use

📘 Documentation, powered by Sphinx, is available at https://acherus.readthedocs.io/

Look at 📁 examples/ for different physical applications:

• 1500 picosecond filamentation of an IR (1032 nm) pulse in air.
• 100 femtosecond filamentation of an IR (800 nm) pulse in air.
• 130 femtosecond filamentation of an IR (800 nm) pulse in water.
• 90 femtosecond filamentation of a UV (400 nm) pulse in water.

Installation

Acherus supports Python 3.11 - 3.14 and may be installed using any venv or conda environment.

📘 Complete installation details can be checked in our Installation Guide.

Install with PyPI

To install Acherus, simply run:

pip install acherus

To install Acherus from the source, clone the repository and install it in editable mode:

git clone https://github.com/ismatorresgarcia/acherus.git
cd acherus
pip install -e .

📌 Have a bug, feature request, or suggestion? Open a GitHub Issue so the community can track it.

👥 Want to contribute? To merge your changes into main, create a Pull Request (PR) following this PR template.

Motivation

🌱 This project is part of research work carried out during the academic years 2024–2026 at the Universidad Politécnica de Madrid.

🎯 The main goal of this thesis is to study the detection of toxic agents and pathogens in the upper layers of the atmosphere by exploiting the presence of molecular nitrogen. These nitrogen molecules can act as an active medium, which amplifies radiation of a specific frequency when interacting with nitrogen, generating laser emission. The interaction between laser light and surrounding matter in the atmosphere can be used to determine the hidden presence of undesired contaminants and to study their physical properties.

🤔 So, what are the main activities or tasks carried out in this project?

• 💻 Developing Maxwell-Bloch numerical codes, as well as studying the propagation of intense infrared plasma lasers through plasma channels —using Particle-in-Cell codes (PIC)— and atomic processes in plasmas.
• 🧪 Developing preprocessing and postprocessing tools to study the data generated by the numerical codes.
• 🌀 Using the previous numerical codes to study the amplification of ultraviolet (UV) radiation in nitrogen plasma filaments.

Citing Acherus

🔖 All Acherus releases are linked automatically to a Zenodo publication under a unique DOI. If you use Acherus in your work, please star this repository so we can track adoption and improve the project. Additionally, if you use Acherus in a scientific publication, please consider citing this work:

[1] I. Torres García et al., "Acherus". Zenodo, 2025. https://doi.org/10.5281/zenodo.15924923

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