Abstract: In MHD equilibrium codes which use a spectral representation of
cylindrical coordinates $R = \sum R_{mn}(s) cos(m \theta - n \phi)$ and $Z =
\sum Z_{mn}(s) sin(m \theta - n \phi)$, the Jacobian is zero at the magnetic
axis, which causes some convergency problems near the axis. A postprocessing
of VMEC output, in particular smoothing of the Fourier components of the
cylindrical coordinates and a consistent recal-culation of the equilibrium
data, is done to get smooth equilibrium data, e.g. smooth Fourier components
of R and Z, near the axis.