Building Up Solar-wind-like 3D Uniform-intensity Magnetic Fields

A numerical model representing a 3D turbulent constant-magnitude magnetic field B is described. Assuming a form for two components of the vector potential, the third component is calculated such as to obtain a uniform intensity for B. Singular surfaces are always present in the solution, in the form of rotational discontinuities. Using a spectrum for derivatives of the given vector potential components that satisfies the critical-balance condition, an anisotropic spectrum for B is obtained, with a prevalence of perpendicular wavevectors k⊥ and a Kolmogorov power-law range with respect to k⊥. These features make the model suitable to represent magnetic turbulence in solar wind fast-speed streams.