Parametric resonances in axionic cosmic strings

In this letter we uncover a new parametric resonance of axionic cosmic strings. This process is triggered by the presence on string internal mode excitations that resonantly amplify amplitude transverse displacements string. We study running numerical simulations demonstrate existence phenomenon in $(3+1)$ dimensional lattice field theory and compare results with analytic expectations for effective Lagrangian these modes their interactions. Finally, also analyze massless massive radiation produced excited strings comment its relevance interpretation current networks.