Unbounded electromagnetic field problem solution by means of virtual GMRES

This paper reviews some solving procedures for unbounded electromagnetic field problems, based on the integral representation of the unknown boundary condition on the truncation fictitious boundary. Three problems are considered: electrostatic, time-harmonic skin effect, and time-harmonic scattering in unbounded domains. These problems are formulated, respectively, by means of the hybrid FEM-BEM, FEM-DBCI and FEM-RBCI methods, which in all cases lead to global algebraic systems which are partly sparse and partly dense. The paper shows that a very good solving strategy is based on the use of the GMRES solver, virtually applied to a suitably reduced algebraic system, in which the unknowns are only the truncation boundary ones.