raytrax 0.4.0

An ECRH ray tracer based on JAX

Raytrax

An ECRH ray tracer for fusion plasmas, built on JAX.

Raytrax simulates Electron Cyclotron Resonance Heating (ECRH) of magnetic confinement fusion plasmas. Powered by JAX, it features JIT-compiled ray tracing and automatic differentiation — making it well-suited for gradient-based beam optimization in fusion plant design.

Note: Raytrax is in early development. Expect API changes and incomplete validation. For details see the docs.

Usage

Load a magnetic equilibrium, define plasma profiles, and trace a beam:

import jax.numpy as jnp
import raytrax
import vmecpp

vmec_wout = vmecpp.VmecWOut.from_wout_file("w7x.nc")
mag_conf = raytrax.MagneticConfiguration.from_vmec_wout(vmec_wout)

rho = jnp.linspace(0, 1, 200)
profiles = raytrax.RadialProfiles(
    rho=rho,
    electron_density=2.0 * (1 - rho**2),
    electron_temperature=3.0 * (1 - rho**2),
)
beam = raytrax.Beam(
    position=jnp.array([6.6, 0.0, 0.0]),
    direction=jnp.array([-0.985, 0.0, -0.174]),
    frequency=140e9,
    mode="O",
    power=1e6,
)

result = raytrax.trace(mag_conf, profiles, beam)

print(f"Optical depth τ     = {result.optical_depth:.3f}")
print(f"Absorbed fraction   = {result.absorbed_power_fraction:.1%}")
print(f"Deposition at ρ     = {result.deposition_rho_mean:.2f} ± {result.deposition_rho_std:.2f}")

Visualizations

Beam trace on a poloidal cross-section

3D visualization

Raytrax can render flux surfaces and beam trajectories in 3D using PyVista:

import pyvista as pv
from raytrax.plot.plot3d import plot_flux_surface_3d, plot_beam_profile_3d

plotter = pv.Plotter()
plot_flux_surface_3d(mag_conf, rho_value=1.0, plotter=plotter, opacity=0.25)
plot_beam_profile_3d(result.beam_profile, plotter=plotter, tube_radius=0.02)
plotter.export_html("scene.html")  # interactive standalone HTML

Try out a live interactive version in the docs.

Jupyter Notebooks

Quick-start notebooks are in the notebooks/ directory.

Installation

python -m pip install raytrax

See the documentation for a full getting-started guide, theory background, and API reference.

Citing Raytrax

If you use Raytrax in your research, please cite it via Zenodo: doi:10.5281/zenodo.18924104.

Acknowledgements

The development of Raytrax is a collaboration between Proxima Fusion and the Munich University of Applied Sciences (HM) and was partially supported by the German Federal Ministry of Research, Technology and Space (BMFTR) under grant FPP-MC (13F1001B).

         

License

Raytrax is released under the MIT License. See LICENSE.md for details.