Zobrazeno 1 - 10
of 21
pro vyhledávání: '"Florian, Wechsung"'
Publikováno v:
Plasma Physics and Controlled Fusion
We introduce a novel approach for the simultaneous optimization of plasma physics and coil engineering objectives using fixed-boundary equilibria that is computationally efficient and applicable to a broad range of vacuum and finite plasma pressure s
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::cb78b0ca8e7f25d7106f70465a961d5c
Publikováno v:
BIT Numerical Mathematics. 61:607-644
We propose a robust and efficient augmented Lagrangian-type preconditioner for solving linearizations of the Oseen–Frank model arising in nematic and cholesteric liquid crystals. By applying the augmented Lagrangian method, the Schur complement of
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::51866cef21a58864223f65aaa2f9d4a8
https://doi.org/10.1007/s10543-020-00838-9
https://doi.org/10.1007/s10543-020-00838-9
A common scientific inverse problem is the placement of magnets that produce a desired magnetic field inside a prescribed volume. This is a key component of stellarator design, and recently permanent magnets have been proposed as a potentially useful
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4c47d7b8d65eee6fe8bc5c7969f5bb6a
http://arxiv.org/abs/2207.08984
http://arxiv.org/abs/2207.08984
Publikováno v:
Proceedings of the National Academy of Sciences. 119
Magnetic fields with quasi-symmetry are known to provide good confinement of charged particles and plasmas, but the extent to which quasi-symmetry can be achieved in practice has remained an open question. Recent work [M. Landreman and E. Paul, Phys.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2ba1c1cf88b16029b5350a26868d8e10
https://doi.org/10.1073/pnas.2202084119
https://doi.org/10.1073/pnas.2202084119
We propose a new method to compute magnetic surfaces that are parametrized in Boozer coordinates for vacuum magnetic fields. We also propose a measure for quasisymmetry on the computed surfaces and use it to design coils that generate a magnetic fiel
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::92d003ae247ebe0d22c49d49c6cc5cbf
http://arxiv.org/abs/2203.03753
http://arxiv.org/abs/2203.03753
Publikováno v:
Physics of Plasmas. 30:042511
We present a robust optimization algorithm for the design of electromagnetic coils that generate vacuum magnetic fields with nested flux surfaces and precise quasi-symmetry. The method is based on a bilevel optimization problem, where the outer coil
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::cd307d41a785eb0fa0c04b4347950cd9
https://doi.org/10.1063/5.0129716
https://doi.org/10.1063/5.0129716
Stochastic and a posteriori optimization to mitigate coil manufacturing errors in stellarator design
It was recently shown in Wechsung et al (2022 Proc. Natl Acad. Sci. USA 119 e2202084119) that there exist electromagnetic coils that generate magnetic fields, which are excellent approximations to quasi-symmetric fields and have very good particle co
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::dea2f1ed7ff707796e8b71edee1e2a79
Publikováno v:
Nuclear Fusion. 62:076034
We extend the single-stage stellarator coil design approach for quasi-symmetry on axis from (Giuliani et al 2020) to additionally take into account coil manufacturing errors. By modeling coil errors independently from the coil discretization, we have
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a1291ade5eeab886ba4fdf84826853ce
https://doi.org/10.1088/1741-4326/ac45f3
https://doi.org/10.1088/1741-4326/ac45f3
Publikováno v:
Transactions on Mathematical Software, 2021, Vol.47(3), pp.1-22 [Peer Reviewed Journal]
Effective relaxation methods are necessary for good multigrid convergence. For many equations, standard Jacobi and Gau{\ss}-Seidel are inadequate, and more sophisticated space decompositions are required; examples include problems with semidefinite t
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8a3d9b906191571ae39f1bd49e480360
https://doi.org/10.1145/3445791
https://doi.org/10.1145/3445791
We present augmented Lagrangian Schur complement preconditioners and robust multigrid methods for incompressible Stokes problems with extreme viscosity variations. Such Stokes systems arise, for instance, upon linearization of nonlinear viscous flow
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::9111034cb961b6bcb70e93f8149e5e6a