E and B polarizations from inhomogeneous and solar surface turbulence |
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Axel Brandenburg Submitted: 2019-04-25 21:32
Abstract: 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.
Authors: Axel Brandenburg, Andrea Bracco, Tina Kahniashvili, Sayan Mandal, Alberto Roper Pol, Gordon J. D. Petrie, Nishant K. Singh
Projects: None
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Publication Status: Astrophys. J. 870, 87 (2019)
Last Modified: 2019-05-01 12:05
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