  In this paper we investigate the dynamics of magnetic helicity in
magnetohydrodynamic (MHD) turbulent flows focusing at scales larger than the
forcing scale. Our results show a nonlocal inverse cascade of magnetic
helicity, which occurs directly from the forcing scale into the largest scales
of the magnetic field. We also observe that no magnetic helicity and no energy
is transferred to an intermediate range of scales sufficiently smaller than the
container size and larger than the forcing scale. Thus, the statistical
properties of this range of scales, which increases with scale separation, is
shown to be described to a large extent by the zero flux solutions of the
absolute statistical equilibrium theory exhibited by the truncated ideal MHD
equations.
