Strong magnetohydrodynamic turbulence with cross helicity
  Magnetohydrodynamics (MHD) provides the simplest description of magnetic
plasma turbulence in a variety of astrophysical and laboratory systems. MHD
turbulence with nonzero cross helicity is often called imbalanced, as it
implies that the energies of Alfv\'en fluctuations propagating parallel and
anti-parallel the background field are not equal. Recent analytical and
numerical studies have revealed that at every scale, MHD turbulence consists of
regions of positive and negative cross helicity, indicating that such
turbulence is inherently locally imbalanced. In this paper, results from high
resolution numerical simulations of steady-state incompressible MHD turbulence,
with and without cross helicity are presented. It is argued that the inertial
range scaling of the energy spectra (E^+ and E^-) of fluctuations moving in
opposite directions is independent of the amount of cross-helicity. When cross
helicity is nonzero, E^+ and E^- maintain the same scaling, but have differing
amplitudes depending on the amount of cross-helicity.
