Effect of small-scale structure on the dynamics of cosmic strings

The effective equation of state for a string with short-wavelength perturbations is shown to be $\mu T={\mu }_0^2$, where $\mu$ and $T$ are the mass density and tension in the rest frame of the string and ${\mu }_0$ is the unperturbed string tension. The dynamics of "wiggly" strings in flat spacetime is discussed. The conclusions are in agreement with the results obtained by Carter using different methods.