Abstract
The relation between the Hamada and the Boozer magnetic coordinate systems is clarified by deriving them from a general magnetic fied coordinate system. The coordinate transformation from the Hamada to the Boozer coordinate system is performed using a transformation function, which is easily calculated with the knowledge of the magnetic field strength only.In non-axisymmetric systems, the Fourier spectrum of the magnetic field strength |B| in the Hamada coordinate system is broader than that in the Boozer coordinate system and the leading modes of IBI in the Hamada coordinate system significantly deviate from a simple model field in comparison with the Boozer coordinate system.The Boozer coordinate system is suitable for numerical calculations, especially, for neoclassical and orbit calculations in non-axisymmetric systems.
