  From microscopic fluid clusters to macroscopic droplets, the structure of
fluids is governed by the Van der Waals force, a force that acts between
polarizable objects. In this Letter, we derive a general theory that describes
the non-equilibrium counterpart to the Van der Waals force, which emerges in
spatially coherently fluctuating electromagnetic fields. We describe the
formation of a novel and complex hierarchy of self-organized morphologies in
magnetic and dielectric colloid systems. Most striking among these morphologies
are dipolar foams - colloidal superstructures that swell against gravity and
display a high sensitivity to the applied field. We discuss the dominance of
many body forces and derive the equation of state for a material formed by the
coherent Van der Waals force. Our theory is applied to recent experiments in
paramagnetic colloidal systems and a new experiment is suggested to test the
theory.
