Gamma-rays from superconducting cosmic strings

Superconducting cosmic strings, predicted in some elementary particle theories, can have dramatic cosmological consequences. Ostriker, Thompson and Witten (OTW) [Phys. Lett. B180, 231-239 (1986)] have shown that the low-frequency electromagnetic radiation from superconducting closed loops can sweep away the surrounding plasma, and have identified the resulting bubbles of radiation with the voids observed in the large-scale distribution of galaxies. Here I discuss some observational consequences of the OTW model. It will be shown that it predicts observable fluxes of γ-rays and ultra-high energy cosmic rays from long strings stretching across the visible universe. (author)