Figure 6

The smallest/largest non-zero eigenvalue for \(\pmb{\varepsilon=0}\) is plotted against the meshwidth for 50 different angles of rotation (dashed lines). For comparison the smallest/largest non-zero eigenvalue of a \(\mathbf {H}(\mathbf {curl})\) conforming discretization based on second order edge functions is plotted as well. The angles are \(\theta= 0.01 n\mbox{ rad}\), \(n\in{0,\ldots, 49}\) and \(R^{2}\) edge functions were used to discretize \(a_{\mathrm{h}}^{\mathrm{SWIP}}\), \(\mu \equiv1\).