On relation between Hamada and Boozer Magnetic Coordinate Systems.

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 I B I 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. Keywords: magnetic coordinate system,Hamada coordinate system,Boozer coordinate system, straight magnetic field line coordinate system,coordinate transformation,non-axi-symmetric system,Fourier spectrum,