Vectorised spectral/hp element matrix-free operator for anisotropic heat transport in tokamak edge plasma

B. Liu, C. D. Cantwell, D. Moxey, M. Green, S. J. Sherwin

8th European Congress on Computational Methods in Applied Sciences and Engineering (2022)

@inproceedings{liu-2022,
  author = {Liu, B. and Cantwell, C. D. and Moxey, D. and Green, M. and Sherwin, S. J.},
  title = {Vectorised spectral/hp element matrix-free operator for anisotropic heat transport in tokamak edge plasma},
  booktitle = {8th European Congress on Computational Methods in Applied Sciences and Engineering},
  doi = {10.23967/eccomas.2022.291},
  url = {https://www.scipedia.com/public/Liu_et_al_2022b},
  year = {2022}
}

Heat transport in the magnetised plasma of a tokamak is strongly anisotropic, and simulating it at the scale a reactor design needs calls for algorithms that stay efficient on large machines. This extended abstract proposes a variational form for the problem and a matrix-free Helmholtz operator in Nektar++ that combines sum-factorisation with SIMD vectorisation, assessed for accuracy and speed on steady and unsteady cases.