Hermes-3 is a multifluid plasma simulation model for transport and turbulence in the edge of magnetically confined plasmas, such as tokamaks. It is built on the BOUT++ framework, and uses a system of reusable components to build models at runtime based on input configuration, in 1D, 2D or 3D curvlinear coordinates. The manual is here on Readthedocs.
Post-processing Hermes-3 is made easy by using the xHermes Python library. xHermes is built on top of xBOUT and Xarray and automatically accounts for the normalisation of Hermes-3 parameters, as well as providing access to many useful xBOUT post-processing functions. Many of these are showcased in the xBOUT examples.
Note Under development, research code, may change without notice.
Hermes-3 is released under the GPL-3 license. See LICENSE and NOTICE for details. If you are using Hermes-3, please cite the relevant papers.
All new contributions must be made under the GPLv3 license.
LLNL-CODE-845139
Copyright Hermes-3 contributors 2017-2026
email: dudson2@llnl.gov
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
Please refer to the documentation for installation instructions.
There are example inputs under the examples/ subdirectory. A simple example is a 2D (drift plane) simulation of a plasma blob/filament, similar to the BOUT++ blob2d example:
./hermes-3 -d examples/blob2d
See the examples for more complicated cases.
- B.Dudson, M.Kryjak, H.Muhammed, P.Hill, J,Omotani Hermes-3: Multi-component plasma simulations with BOUT++ Comp. Phys. Comm. 108991 (2023). doi:10.1016/j.cpc.2023.108991. Preprint: arXiv.2303.12131.
- G.K. Holt, A. Keats, S. Pamela, M. Kryjak, A. Agnello, N.C. Amorisco, B.D. Dudson and M. Smyrnakis Tokamak divertor plasma emulation with machine learning Nucl. Fusion 64 086009 (2024) doi:10.1088/1741-4326/ad4f9e
- Thomas Body, Thomas Eich, Adam Kuang, Tom Looby, Mike Kryjak, Ben Dudson, Matthew Reinke Detachment scalings derived from 1D scrape-off-layer simulations Nucl. Mat. Energy 2024 101819 doi:10.1016/j.nme.2024.101819
- Huayi Chang, Ben Dudson, Jizhong Sun, Mike Kryjak, Yang Ye, Mao Li, Weikang Wang Hermes-3 simulation of the low-n X-point mode driven by impurity in tokamak edge plasmas Nucl. Mat. Energy 2025 101913 doi:10.1016/j.nme.2025.101913
- B. D. Dudson, M. Kryjak, H. Muhammed, J. Omotani Validation of Hermes-3 turbulence simulations against the TCV-X21 diverted L-mode reference case 2025 Preprint: arXiv:2506.12180.
- M. V. Umansky, B. D. Dudson, T. G. Jenkins, J. R. Myra, D. N. Smithe Modeling of convective cells, turbulence, and transport induced by a radio-frequency antenna in the tokamak boundary plasma Plasma Phys. Control. Fusion 67 115025 (2025) doi:https://doi.org/10.1088/1361-6587/ae1bd1 Preprint: arXiv:2509.08178
- J. L. Baker, M. Kryjak, M. R. K. Wigram, S. Mijin, D. Power, B. D. Dudson and C. P. Ridgers The impact of non-local fluid models on 1D impurity driven detachment in an ITER-like SOL Plasma Phys. Control. Fusion 68(4) 045032 2026 doi:10.1088/1361-6587/ae56b4
- M. Robinson, A. Scarabosio, E. Vekshina, J.H. Nichols, J.D. Lore, K. Borowiec, J. Varje, S.M. Levine, M. Scarpari, E.N.J. Maartensson, X. Zhang, R. Kamenicky, J. Alexander, M. Jackson, C. Marsden, S.A.M. McNamara and R. Maingi Power and particle exhaust in the ST-E1 fusion power plant Nucl. Fusion 66 086011 2026 doi:10.1088/1741-4326/ae70a0
- Khan, M and Kryjak, M and Cziegler, I and Dudson, B and Henderson, S and Moulton, D and Osawa, R and Ridgers, C P The role of momentum transfer in the detachment front response to power transients for reactor scale tokamaks Nucl. Fusion 66 096032 2026 doi:10.1088/1741-4326/ae91f8