Spectral asymmetry due to magnetic coordinates

The use of magnetic coordinates is ubiquitous in toroidal plasma physics but the distortion in Fourier spectra produced by these coordinates is not well known. A spatial symmetry of the field is not always represented by a symmetry in the Fourier spectrum when magnetic coordinates are used because of the distortion of the toroidal angle. The practical importance of spectral distortion is illustrated with a tokamak example.