Magnetic screening in high-energy heavy-ion collisions

We show that classical chromomagnetic fields produced coherently in the initial stage of a heavy-ion collision exhibit screening. From the two-point field strength correlator we determine the magnetic mass for SU(2) to be m ~ 5 times the saturation scale. Magnetic screening leads to an intuitive understanding of the area law scaling of spatial Wilson loops observed previously. The presence of screening effects in the initial state provides a basis for defining kinetic processes in the early stage of heavy-ion collisions, with electric and magnetic masses of the same order.