Analysis of the Toroidal Magnetic Field in the Heliotron C Device

Abstract

An analysis of the magnetic field produced by a current flowing in the Heliotron C coils is carried out. Under the assumption that radius of coils is much smaller than that of torus, the calculation resorts to the perturbation method in which all quantities are expanded in ka, where k is the curvature of torus and a the radius of coil. The Heliotron C magnetic field is obtained analytically as the function of coil radius, the current ratio of adjacent coils, the distance of adjacent colis and the curvatre of torus. The accuracy of this analyzed magnetic field is examined according to whether the position of neutral line calculated by the obtained formula agrees with that of experiment or not.