def plot_forward_models(self):
        """Plot the forward models (requires the forward models to be loaded)
        """
        pids_rho = self.assignments.get('forward_model', None)
        if pids_rho is None:
            raise Exception('you need to load the forward model first')
        fig, axes = plt.subplots(1, 2, figsize=(16 / 2.54, 8 / 2.54))
        ax = axes[0]
        self.plot.plot_elements_to_ax(
            pids_rho[0],
            ax=ax,
            plot_colorbar=True,
            cblabel=r'$|\rho| [\Omega m]$',
        )

        ax = axes[1]
        self.plot.plot_elements_to_ax(
            pids_rho[1],
            ax=ax,
            plot_colorbar=True,
            cblabel=r'$\phi [mrad]$',
        )
        fig.tight_layout()
        return fig, axes