• Fast

    Powered by SHTns, the blazingly fast spherical harmonic transform library.
    Xshells was designed for speed from the ground up.

  • Versatile

    Easy to use, with a nice user manual and example parameter files for geodynamo, double-diffusive convection, precession, spherical Couette, ...

  • Scalable

    Runs from your laptop to massively parallel and GPU accelerated supercomputers, using both MPI, OpenMP and CUDA/HIP.

  • Free and Open

    Distributed under the CeCILL License (compatible with GNU GPL). Everybody is free to use, modify, contribute.

  • Visualization ready

    Tools for post-processing and visualization in python and paraview are provided.

  • Validated

    Xshells passes the geodynamo benchmarks and the full-sphere benchmarks.

High-definition turbulent geodynamo

Using the xshells code on thousands of computer cores allowed to simulate the generation of the Earth's magnetic field with unprecedented resolution.
Schaeffer et al. 2017 doi:10.1093/gji/ggx265

Precession-driven dynamos

When a sphere precesses, the fluid rotates along an axis distinct from that of the solid outer sphere. This can lead to turbulence and generation of a magnetic field, and has applications to some planets and moons.
Cébron et al. 2019 doi:10.1093/gji/ggz037

Rapidly-rotating thermal convection

At high thermal diffusivity (like a liquid metal) and at high rotation rate (like a planetary core), the onset of convection is subcritial, the flow is always turbulent, while retaining the columnar structure due to the Coriolis force.
Kaplan et al. 2017 doi:10.1103/PhysRevLett.119.094501
Guervilly et al. 2019 doi:10.1038/s41586-019-1301-5

Simulating a liquid-metal spherical Couette experiment

Various regimes of flow in the DTS experiment are identified and characterized using direct numerical simulations using parameters close to the actual ones.
Kaplan et al. 2018 doi:10.1103/PhysRevFluids.3.034608