A New Regime for Dense String Networks in the One Scale Model with Friction

Abstract

We examine the compatibility between the one scale model with friction for the evolution of cosmic string networks with the Kibble mechanism for string network formation during a second order phase transition. We find a regime which connects (in a dramatically short time $\sim .1 t_c$) the dense string network (small network scale $L\sim 1/T_c$) created by the Kibble {\it{mechanism}} to the (dilute) Kibble {\it{regime}}(L\sim t^{3/4} in which friction dominated strings remain till times $t_*\sim (M_P/T_c)^2t_c$. The enormous loss of string length implied by this result is due to the continued dissipative motion of the string network which follows from the one scale model's identification of the typical curvature radius with the network scale and the fact that the cosmological phase transition time $t_c\sim M_{Planck}/T_c^2$ is much larger than the damping time scale $l_f\sim T_c^2/T^3$. The significant implications for string mediated Baryogenisis are also discussed briefly.