Stability analysis of NET TF and PF conductors

The transient stability behavior of the different conductors proposed for the Next European Torus toroidal and poloidal field magnets has been studied. A conceptually simple, length-independent computer model has been refined to analyze the time-dependent response of the conductors to sudden energy inputs over a wide range of pulse duration, pulse shape, and transient-heat-transfer coefficients. Some conductors exhibit a sudden transition from a high-stability (well-cooled) to a low-stability (ill-cooled) regime under certain operating conditions. A simple expression is given for prediction of this transition point. Implications for the NET coil designs are discussed.