Empirical formulas for estimating self and mutual inductances of toroidal field coils and structures

Self and mutual inductances of toroidal-field (TF) coils are empirically expressed by linear combinations of three coil-shape parameters: elongation, aspect ratio, and triangularity, based on their calculation results with the Neumann formula. A regression function was also obtained for calculating rough values of self-inductances of toroidal-shape structures such as a vacuum vessel in a Tokamak-type fusion reactor. An analysis for their eddy currents induced during fast discharge of TF coils is presented for showing as an application example of these formulas. (author)