Block triangular preconditioners for the discretized time-harmonic Maxwell equations in mixed form

In this paper, we consider the solution of the saddle point linear systems arising from the finite element discretization of the time-harmonic Maxwell equations in mixed form. Two types of block triangular Schur complement-free preconditioners used with Krylov subspace methods are proposed, involving the choice of the parameter. Furthermore, we give the optimal parameter in practice. Theoretical analysis shows that all eigenvalues of the preconditioned matrices are strongly clustered. Finally, numerical experiments that validate the analysis are presented.