We examine the spectrum of gravitational radiation emitted by a network of cosmic strings , with emphasis on the observational constraints and the opportunities for detection .
The analysis improves over past work , as we use a phenomenological model for the radiation spectrum emitted by a cosmic string loop .
This model attempts to include the effect of the gravitational back-reaction on the radiation emission by an individual loop with a high frequency cut-off in the spectrum .
Comparison of the total spectrum due to a network of strings with the recently improved bound on the amplitude of a stochastic gravitational wave background , due to measurements of noise in pulsar signal arrival times , allows us to exclude a range of values of \mu , the cosmic string linear mass density , for certain values of cosmic string and cosmological parameters .
We find the conservative bound G \mu / c ^ { 2 } < 5.4 ( \pm 1.1 ) \times 10 ^ { -6 } which is consistent with all other limits .
We consider variations of the standard cosmological scenario , finding that an under dense , \Omega _ { 0 } < 1 universe has little effect on the spectrum , whereas the portion of the spectrum probed by gravitational wave detectors is strongly sensitive to the thermal history of the cosmological fluid .
We discuss the opportunity for the observation of this stochastic background by resonant mass and laser interferometer gravitational wave detectors .