We investigate the anisotropy of Alfvénic turbulence in the inertial range of slow solar wind and in both driven and decaying reduced magnetohydrodynamic simulations .
A direct comparison is made by measuring the anisotropic second-order structure functions in both data sets .
In the solar wind , the perpendicular spectral index of the magnetic field is close to -5 / 3 .
In the forced simulation , it is close to -5 / 3 for the velocity and -3 / 2 for the magnetic field .
In the decaying simulation , it is -5 / 3 for both fields .
The spectral index becomes steeper at small angles to the local magnetic field direction in all cases .
We also show that when using the global rather than local mean field , the anisotropic scaling of the simulations can not always be properly measured .