Open AccessComputation of lossy higher order modes in complex SRF cavities using Beyn’s and Newton’s methods on reduced order models
Author(s) -
Hermann W. Pommerenke,
Johann Heller,
Shahnam Gorgi Zadeh,
Ursula van Rienen
Publication year - 2019
Publication title -
international journal of modern physics a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.581
H-Index - 108
eISSN - 1793-656X
pISSN - 0217-751X
DOI - 10.1142/s0217751x19420375
Subject(s) - physics , eigenvalues and eigenvectors , computation , nonlinear system , algorithm , mathematics , topology (electrical circuits) , computer science , quantum mechanics , combinatorics
Superconducting radio frequency cavities meet the demanding performance requirements of modern accelerators and high-brilliance light sources. Their design requires a precise knowledge of their electromagnetic resonances. A numerical solution of Maxwell’s equations is required to compute the resonant eigenmodes, their frequencies and losses due to the complex cavity shape. The consideration of resonances damped by external losses leads to a nonlinear eigenvalue problem. Previous work showed that, using State-Space Concatenation to construct a reduced order model and Newton iteration to solve the arising eigenvalue problem, solutions can be obtained on workstation computers even for large-scale problems without extensive simplification of the structure itself. In this paper, we augment the solution workflow by Beyn’s contour integral algorithm to increase the number of found eigenmodes. Numerical experiments are presented for one academic and two real-life superconducting cavities and partially compared to measurements.