Efficient full wave code for the coupling of large multirow multijunction LH grills

0480957 - ÚFP 2018 RIV AT eng J - Journal Article
Preinhaelter, Josef - Hillairet, J. - Milanesio, D. - Maggiora, R. - Urban, Jakub - Vahala, L. - Vahala, G.
Efficient full wave code for the coupling of large multirow multijunction LH grills.
Nuclear Fusion. Roč. 57, č. 11 (2017), č. článku 116060. ISSN 0029-5515. E-ISSN 1741-4326
R&D Projects: GA MŠMT(CZ) 8D15001; GA MŠMT(CZ) LM2015045
Institutional support: RVO:61389021
Keywords : lower hybrid waves * coupling * large multirow multijunction grills * tokamak * full-wave
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 4.057, year: 2017
http://iopscience.iop.org/article/10.1088/1741-4326/aa7f4f/meta

The full wave code OLGA, for determining the coupling of a single row lower hybrid launcher (waveguide grills) to the plasma, is extended to handle multirow multijunction active passive structures (like the C3 and C4 launchers on TORE SUPRA) by implementing the scattering matrix formalism. The extended code is still computationally fast because of the use of (i) 2D splines of the plasma surface admittance in the accessibility region of the k-space, (ii) high order Gaussian quadrature rules for the integration of the coupling elements and (iii) utilizing the symmetries of the coupling elements in the multiperiodic structures. The extended OLGA code is benchmarked against the ALOHA-1D, ALOHA-2D and TOPLHA codes for the coupling of the C3 and C4 TORE SUPRA launchers for several plasma configurations derived from reflectometry and interferometery. Unlike nearly all codes (except the ALOHA-1D code), OLGA does not require large computational resources and can be used for everyday usage in planning experimental runs. In particular, it is shown that the OLGA code correctly handles the coupling of the C3 and C4 launchers over a very wide range of plasma densities in front of the grill.
Permanent Link: http://hdl.handle.net/11104/0276600