Dimensionless error associated with the divergence of the magnetic field, defined as |∇ ∙ B|∆x/(|B| + 〈|B|〉_h). The top three panels show the maximum and average values of this error as functions of time. The left panels correspond to the simulation with an initially vertical magnetic field, while the right panels show the results for the arcade magnetic field configuration. The first row presents values computed over the entire domain, while the second and third rows show values at heights of z=0 Mm and z =10 Mm, respectively. The bottom color maps display the error in logarithmic scale for both simulations for t=2800 s.