E and B polarizations from inhomogeneous and solar surface turbulence
  Gradient- and curl-type or E- and B-type polarizations have been routinely
analyzed to study the physics contributing to the cosmic microwave background
polarization and galactic foregrounds. They characterize the parity-even and
parity-odd properties of the underlying physical mechanisms, for example
hydromagnetic turbulence in the case of dust polarization. Here we study
spectral correlation functions characterizing the parity-even and parity-odd
parts of linear polarization for homogeneous and inhomogeneous turbulence to
show that only the inhomogeneous helical case can give rise to a parity-odd
polarization signal. We also study nonhelical turbulence and suggest that a
strong nonvanishing (here negative) skewness of the E polarization is
responsible for an enhanced ratio of the EE to the BB (quadratic) correlation
in both helical and nonhelical cases. This could explain the enhanced EE/BB
ratio observed recently for dust polarization. We close with a preliminary
assessment of using linear polarization of the Sun to characterize its helical
turbulence without being subjected to the pi ambiguity that magnetic inversion
techniques have to address.
