Magnetic flux loops in high-energy heavy-ion collisions

I discuss the structure of longitudinal chromomagnetic fields whichdevelop in heavy-ion collisions. Rather than being homogeneous, Bz isfound to exhibit domain-like structures in the transverse plane. Theexpectation values of spatial Wilson loops exhibit area law scalingfor radii larger than the inverse saturation momentum, indicatinguncorrelated magnetic flux fluctuations at such scales. Thecorresponding spatial string tension is approximately invariantunder a Z(2) rotation of the SU(2) Wilson loops. I discuss thefailure of a naive perturbative expansion to reproduce area lawscaling and the role of magnetic screening.