Numerical analysis of the dynamics of a cosmic string loop as a vortex

Time evolution of a circular cosmic string loop is investigated by numerically solving the field equations for the scalar and the gauge fields consisting of the vortex. It is shown that the result agrees with an analytic estimate based on the Nambu-Goto action, which supports its validity in analyzing non-straight and rapidly moving strings. The bound on the finite-width correction to the Nambu-Goto action is also obtained.