  In this paper we perform a dynamical analysis for a vector field as a
candidate for the dark energy, in the presence of a barothropic fluid. The
vector is one component of the so-called cosmic triad, which is a set of three
identical copies of an abelian field pointing mutually in orthogonal
directions. In order to generalize the analysis, we also assumed the
interaction between dark energy and the barotropic fluid, with a
phenomenological coupling. Both matter and dark energy eras can be successfully
described by the critical points, indicating that the dynamical system theory
is a viable tool to analyze asymptotic states of such cosmological models.
