  On a warped five-dimensional Friedmann-Lema\^{\i}tre-Robertson-Walker(FLRW)
spacetime, dark energy can be induced by a U(1) scalar-gauge field on the
brane. We consider a zero effective cosmological constant, i.e., the
Randall-Sundrum(RS) fine-tuning and no bulk matter fields. The standard model
fields interact via the bulk Weyl tensor and cause brane fluctuations. Due to
the warp factor, disturbances don't fade away during the expansion of the
universe. The late-time behavior could be significant deviate from the standard
evolution of the universe. The effect is triggered by the time-dependent part
of the warp factor. The self-gravitating cosmic string builds up a huge mass
per unit length in the bulk and can induce massive KK-modes felt on the brane.
From a nonlinear perturbation analysis it is found that the effective Einstein
equations contain a "back-reaction" term on the righthand side caused by the
projected 5D Weyl tensor and can act as a dark energy term. The propagation
equations to first order for the metric components and scalar-gauge fields show
explicit $\varphi$-dependency.
