\documentclass[a4paper,11pt]{article} \title{Eigenvalue solvers for electromagnetic fields in cavities} \author{\underline{Peter Arbenz} and Roman Geus \\ Swiss Federal Institute of Technology (ETH) \\ Institute of Scientific Computing \\ CH-8092 Zurich, Switzerland \\[.5cm] Email: \texttt{[arbenz,geus]@inf.ethz.ch} \\ WWW: \texttt{http://www.inf.ethz.ch/personal/arbenz/} } \date{} \begin{document} \maketitle \thispagestyle{empty} \begin{abstract} We investigate algorithms for computing steady state electromagnetic waves in cavities. The Maxwell equations for the strength of the electric field are solved by (1) a penalty method using common linear and quadratic Lagrange (node-based) tetrahedral finite elements, and (2) a mixed method with linear and quadratic finite edge elements for the field values and corresponding node-based finite elements for the Lagrange multiplier. These are two approaches that avoid so-called spurious modes which are introduced if the di\-ver\-gence-free condition for the electric field is not treated properly. The resulting large sparse matrix eigenvalue problems have been solved (1) implicitly restarted Lanczos algorithm and (2) Jacobi-Davidson algorithm. For all finite element approximations we compare the amount of work it takes each solver to compute a few of the smallest positive eigenvalues and corresponding eigenmodes to a given accuracy. Numerical results obtained on an HP Exemplar X-Class System are presented. \end{abstract} \end{document}