  Gravitational waves emitted by kinks on infinite strings are investigated
using detailed estimations of the kink distribution on infinite strings. We
find that gravitational waves from kinks can be detected by future pulsar
timing experiments such as SKA for an appropriate value of the the string
tension, if the typical size of string loops is much smaller than the horizon
at their formation. Moreover, the gravitational wave spectrum depends on the
thermal history of the Universe and hence it can be used as a probe into the
early evolution of the Universe.
