Compensating Faraday depolarization by magnetic helicity in the solar corona

Abstract

A turbulent dynamo in spherical geometry with an outer corona is simulated to study the sign of magnetic helicity in the outer parts. In agreement with earlier studies, the sign in the outer corona is found to be opposite to that inside the dynamo. Line-of-sight observations of polarized emission are synthesized to explore the feasibility of using the local reduction of Faraday depolarization to infer the sign of helicity of magnetic fields in the solar corona. This approach was previously identified as an observational diagnostic in the context of galactic magnetic fields. Based on our simulations, we show that this method can be successful in the solar context if sufficient statistics is gathered by using averages over ring segments in the corona separately for the regions north and south of the solar equator.

arXiv comment5 pages, 3 figures, published in ApJL

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Cited by in corpus (4)

• Advances in mean-field dynamo theory and applications to astrophysical turbulence
• Turbulent processes and mean-field dynamo
• Magnetic Helicity Reversal in the Corona at Small Plasma Beta
• A global two-scale helicity proxy from $\pi$-ambiguous solar magnetic fields