  Gauge invariance plays an important role in forming topological defects. In
this work, from the AdS/CFT correspondence, we realize the clusters of
equal-sign vortices during the course of critical dynamics of a strongly
coupled superconductor. This is the first time to achieve the equal-sign vortex
clusters in strongly coupled systems, considering that vortices with equal sign
repel. The appearance of clusters of equal-sign vortices is a typical character
of flux trapping mechanism, distinct from Kibble-Zurek mechanism which merely
presents vortex-antivortex pair distributions resulting from global symmetry
breaking. Numerical results of spatial correlations and net fluxes of the
equal-sign vortex clusters quantitatively support the positive correlations
between vortices. The linear dependence between the vortex number and the
amplitude of magnetic field at the `trapping' time demonstrates the flux
trapping mechanism very well.
