R Brandenbergcr - physical Department , McGill University,Montreal
H Firouzjahi - School of Physics Institute of Reseurch in Fundamental Sciences(IPM),Tehran.Iran
j Karouby - Physica Department , McGill Uiversiy, Montreal
S Khosravi - School of Astronomy , Institute for Research in Fundamental Sciences(IPM) Tehran

The formalism for computing the gravitational power radiation from excitations on cosmic slrings forming a junction is presented and applied to the simple case of co-planer strings at a junction when the exeitations are generated along one stirng leg. The effects of polarization of the excitations and of the back-rcaction of the gravitational radiation on the small scale structure of the strings are studied.