@article{121,
  keywords = {fusion plasma, plasma devices, plasma confinement},
  author = {Richard Nies},
  title = {Adjoint methods for quasi-symmetry of vacuum fields on a surface*},
  abstract = {<p>Adjoint methods can speed up stellarator optimisation by providing gradient information more efficiently compared with finite-difference evaluations. Adjoint methods are herein applied to vacuum magnetic fields, with objective functions targeting quasi-symmetry and a rotational transform value on a surface. To measure quasi-symmetry, a novel way of evaluating approximate flux coordinates on a single flux surface without the assumption of a neighbourhood of flux surfaces is proposed. The shape gradients obtained from the adjoint formalism are evaluated numerically and verified against finite-difference evaluations.</p>
},
  year = {2020},
  journal = {Journal of Plasma Physics},
  volume = {88},
  edition = {2022/01/21},
  number = {1},
  pages = {905880106},
  month = {10/2020},
  publisher = {Cambridge University Press},
  issn = {0022-3778},
  url = {https://doi.org/10.1017/S0022377821001264},
  doi = {10.1017/S0022377821001264},
  note = {905880106},
}