I discuss the structure of longitudinal chromomagnetic fields which develop in heavy-ion collisions. Rather than being homogeneous, Bz is found to exhibit domain-like structures in the transverse plane. The expectation values of spatial Wilson loops exhibit area law scaling for radii larger than the inverse saturation momentum, indicating uncorrelated magnetic flux fluctuations at such scales. The corresponding spatial string tension is approximately invariant under a Z(2) rotation of the SU(2) Wilson loops. I discuss the failure of a naive perturbative expansion to reproduce area law scaling and the role of magnetic screening.