Scaling Properties of Three-Dimensional Magnetohydrodynamic Turbulence

The scaling properties of three-dimensional magnetohydrodynamic turbulence with finite magnetic helicity are obtained from direct numerical simulations using 512³ modes. The results indicate that the turbulence does not follow the Iroshnikov-Kraichnan phenomenology. The scaling exponents of the structure functions can be described by a modified She-Leveque model ζ_p = p/9+1-\(1/3\)^p/3, corresponding to basic Kolmogorov scaling and sheetlike dissipative structures. In particular, we find ζ₂~=0.7, consistent with the energy spectrum E_k~k^-5/3 as observed in the solar wind, and ζ₃~=1, confirming a recent analytical result.