Electromagnetic back-reaction from currents on a straight string

TL;DR

This paper analyzes how electromagnetic back-reaction prevents infinite current growth on a straight superconducting cosmic string, showing that fields and currents decay to avoid divergence, with implications for gravitational effects.

Contribution

It provides a detailed calculation of electromagnetic back-reaction on a cosmic string, demonstrating the natural damping mechanism preventing divergence of currents.

Findings

Electromagnetic fields and currents decay rapidly enough to prevent divergence.

Back-reaction effectively dampens the current asymptotically to zero.

Implications discussed for gravitational analogs.

Abstract

Charge carriers moving at the speed of light along a straight, superconducting cosmic string carry with them a logarithmically divergent slab of electromagnetic field energy. Thus no finite local input can induce a current that travels unimpeded to infinity. Rather, electromagnetic back-reaction must damp this current asymptotically to nothing. We compute this back-reaction and find that the electromagnetic fields and currents decline exactly as rapidly as necessary to prevent a divergence. We briefly discuss the corresponding gravitational situation.