Cosmic Sparks from Superconducting Strings

We investigate cosmic sparks from cusps on superconducting cosmic strings in light of the recently discovered millisecond radio burst by Lorimer et al.. We find that the observed duration, fluence, spectrum, and event rate can be reasonably explained by grand unification scale superconducting cosmic strings that carry currents $\sim {10}^5\mathrm{GeV}$. The superconducting string model predicts an event rate that falls off only as $S^{-1/2}$, where $S$ is the energy flux, and hence predicts a population of very bright bursts. Other surveys, with different observational parameters, are shown to impose tight constraints on the superconducting string model.

Figure 1

String segment with current $i_0$ at 3 different times, with a cusp at O, with velocity along $z$. The size of the curved section of string is $L$. The observer is at an angle ${\theta }_0$ from the $z$ axis at a distance $d$.

Figure 2

Event rates for PARKES and STARE survey parameters. The vertical line at $30\mathrm{Jy}$ corresponds to the inferred rate from the PARKES survey and at $80000\mathrm{Jy}$ shows the constraint from the STARE survey.