  We investigate numerically the long-time behavior of balanced Alfven wave
turbulence forced at intermediate scales. Whereas the usual constant-flux
solution is found at the smallest scales, two new scalings are obtained at the
forcing scales and at the largest scales of the system. In the latter case we
show, in particular, that the spectrum evolves first to a state determined by
Loitsyansky invariant and later a state close to the thermodynamic
equipartition solution predicted by wave turbulence. The astrophysical
implications for galactic magnetic field generation are discussed.
