  Superconductivity and charge density waves (CDW) are competitive, yet
coexisting orders in cuprate superconductors. To understand their microscopic
interdependence, a probe capable of discerning their interaction on its natural
length and time scales is necessary. We use ultrafast resonant soft x-ray
scattering to track the transient evolution of CDW correlations in
YBa$_{2}$Cu$_{3}$O$_{6+x}$ following the quench of superconductivity by an
infrared laser pulse. We observe a non-thermal response of the CDW order
characterized by a near doubling of the correlation length within $\approx$ 1
picosecond of the superconducting quench. Our results are consistent with a
model in which the interaction between superconductivity and CDW manifests
inhomogeneously through disruption of spatial coherence, with superconductivity
playing the dominant role in stabilizing CDW topological defects, such as
discommensurations.
