FINITE ELEMENT SOLUTION OF A RADIATION/PROPAGATION PROBLEM FOR A HELMHOLTZ EQUATION WITH A COMPACTLY SUPPORTED NONLINEARITY
Keywords:
Scattering, radiation, nonlinear Helmholtz equation, nonlinearly polarizable medium, DtN operator, truncation, finite element methodDOI:
https://doi.org/10.17654/0972096023016Abstract
A finite element method for approximating the solution of a mathematical model for the response of a penetrable, bounded object (obstacle) to the excitation by an external electromagnetic field is presented and investigated. The model consists of a nonlinear Helmholtz equation that is reduced to a spherical domain.
The (exemplary) finite element method is formed by Courant-type elements with curved facets at the boundary of the spherical computational domain. This method is examined for its well-posedness, in particular the validity of a discrete inf-sup condition of the modified sesquilinear form uniformly with respect to both the truncation and the mesh parameters is shown. Under suitable assumptions to the nonlinearities, a quasi-optimal error estimate is obtained. Finally, the satisfiability of the approximation property of the finite element space required for the solvability of a class of adjoint linear problems is discussed.
Received: July 22, 2023
Accepted: September 14, 2023
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