Nested polyhedra model of isotropic magnetohydrodynamic turbulence

Imbalanced Weak Magnetohydrodynamic Turbulence

WeakMHD turbulence consists of waves that propagate along magnetic field lines, in both directions. When two oppositely directed waves collide, they distort each other, without changing their respective energies. Each wave suffers many collisions before cascading; by contrast, in strong MHD turbulence, waves cascade on the same timescale at which they collide. ‘‘ Imbalance ’’ means that more en...

Anisotropic scaling of magnetohydrodynamic turbulence.

We present a quantitative estimate of the anisotropic power and scaling of magnetic field fluctuations in inertial range magnetohydrodynamic turbulence, using a novel wavelet technique applied to spacecraft measurements in the solar wind. We show for the first time that, when the local magnetic field direction is parallel to the flow, the spacecraft-frame spectrum has a spectral index near 2. T...

Subgrid-scale modeling of isotropic turbulence in compressible magnetohydrodynamic large eddy simulations

Despite the ever increasing availability of computational resources, fully resolved simulations of magnetohydrodynamic (MHD) turbulence are not going to be feasible for quite some time. For this reason, large eddy simulations (LES) have been introduced that only resolve large scales. In LES a low-pass filter is applied to the evolution equations, which introduces additional unknown terms. These...

Spectrum of weak magnetohydrodynamic turbulence.

Turbulence of magnetohydrodynamic waves in nature and in the laboratory is generally cross-helical or nonbalanced, in that the energies of Alfvén waves moving in opposite directions along the guide magnetic field are unequal. Based on high-resolution numerical simulations it is proposed that such turbulence spontaneously generates a condensate of the residual energy E(v) - E(b) at small field-p...

A non-local shell model of hydrodynamic and magnetohydrodynamic turbulence