EXTERNAL INDUCTANCE OF LARGE TO ULTRALOW ASPECT-RATIO TOKAMAK PLASMAS

This paper presents a method for calculating the external inductance a nd mutual inductance coefficients of tokamak plasma configurations in a consistent way. The method actually solves the external equilibrium problem, Linking the poloidal equilibrium fields with the value of the total plasma current and the geometric parameters that describe the p lasma cross section. This link imposes constraints upon the values of the inductance for superconducting tori obtained by a previous method described by S. P. Hirshman and G. H. Neilson [Phys. Fluids 29, 790 (1 986)]. Only if these constraints are properly taken into account do th eir results correspond to real tokamak equilibrium configurations. The present method is illustrated by calculating the external equilibrium parameters for a wide range of values of the tokamak aspect ratio. Of particular interest are the results for the external inductance, the elongation, and the vertical equilibrium field in the low aspect-ratio range A < 1.5. (C) 1998 American Institute of Physics. [S1070-664X(98 )01506-7]