Assessment of numerical resistivity (normalized, see Eq. (14)) as a function of grid points per wavelength for a 1D static diffusion test (series A) as well as propagating 1D plasma waves (series B and C, i.e., fast and Alfvén). Numerical fit parameters (Table 1) are obtained for the data points of the m = 1 mode (dashed lines). For series C, the discretization order of the numerical derivatives in the calculation of the current j_∥ has significant impact on the order of convergence. Thick lines in the background employ standard fourth-order finite differences in the calculation of reconstruction of j_∥, while solid thin lines display the improved high-order finite differences (Sect. 3.4, Paper I).