  Scaling laws for ion temperature gradient driven turbulence in magnetized
toroidal plasmas are derived and compared with direct numerical simulations.
Predicted dependences of turbulence fluctuation amplitudes, spatial scales, and
resulting heat fluxes on temperature gradient and magnetic field line pitch are
found to agree with numerical results in both the driving and inertial ranges.
Evidence is provided to support the critical balance conjecture that parallel
streaming and nonlinear perpendicular decorrelation times are comparable at all
spatial scales, leading to a scaling relationship between parallel and
perpendicular spatial scales. This indicates that even strongly magnetized
plasma turbulence is intrinsically three-dimensional.
