Natural frequency spectrum of a flat superconducting cable

A matrix method is used to investigate the current damping process in a fla t superconducting cable. A discrete spectrum of natural frequencies is obta ined, each determining the rate of exponential damping of the corresponding induced current. Although the number of natural frequencies increases as t he size of the cable increases, their spectrum remains finite because the m aximum and minimum frequencies tend to finite limits. An analysis is made o f the induced currents for the limiting frequencies. It is shown that in th e range of minimum natural frequencies the induced currents are long-lived long current loops. At high frequencies the distribution of the induced cur rents in cable layers is sinusoidal. (C) 1999 American Institute of Physics . [S1063-7850(99)00907-6].