Electrical conduction and Joule effect in one-dimensional chains of metallic beads: hysteresis under cycling DC currents and influence of electromagnetic pulses

Abstract

Thepassageofanelectriccurrentthroughachain of metallic beads causes a contact temperature rise and a permanent change of the contact area between beads, which in turn modify the electrical resistance of the chain. These effects are analyzed by measuring the voltage-current char- acteristics of a chain. These characteristics exhibit nonlin- ear and hysteretic behaviors. In this article, we particularly focus on the electrical behavior under cycles of increasing and decreasing current. Experimental results compare well with those of a model derived on the assumption of equi- librium between Joule heating in the contact between beads and thermal dissipation by conduction within the material. It is shown however that models based on the Wiedemann- Franz's law fail to describe the electro-thermo-mechanical behaviors of chains of beads carrying currents and submitted to a small static compression force. We finally analyze the strong modifications of the electrical behavior of a chain of beads subjected to electromagnetic perturbations produced by a spark.