Heat evolution due to pulsed thermal perturbations in superconducting composites with a nonuniformly distributed current

Dissipative processes in superconducting composites under the action of current and pulsed thermal perturbations are studied. Results obtained are compared with the predictions following from the existing theory of thermal stabilization of superconducting composites. It is shown that, if the current is nonuniformly distributed over the composite's cross section and the thermal perturbations are short, intense additional energy dissipation may arise both before and after the occurrence of thermomagnetic instability. Associated Joule heat evolution may substantially exceed the thermal loss predicted by the adopted theory of thermal stabilization throughout the temperature range of the composite. Additional dissipation in composite superconductors narrows the range of stable superconductivity, especially when the current is applied continuously, even if external thermal perturbations are weak.