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arXiv · 1008.4226

Alleviating alpha quenching by solar wind and meridional flow

Dhrubaditya Mitra·David Moss·Reza Tavakol·Axel Brandenburg
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Abstract

We study the ability of magnetic helicity expulsion to alleviate catastrophic $α$-quenching in mean field dynamos in two--dimensional spherical wedge domains. Motivated by the physical state of the outer regions of the Sun, we consider $α^2Ω$ mean field models with a dynamical $α$ quenching. We include two mechanisms which have the potential to facilitate helicity expulsion, namely advection by a mean flow ("solar wind") and meridional circulation. We find that a wind alone can prevent catastrophic quenching, with the field saturating at finite amplitude. In certain parameter ranges, the presence of a large-scale meridional circulation can reinforce this alleviation. However, the saturated field strengths are typically below the equipartition field strength. We discuss possible mechanisms that might increase the saturated field.

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Dhrubaditya Mitra, David Moss, Reza Tavakol, Axel Brandenburg. 2011-01-29. Alleviating alpha quenching by solar wind and meridional flow. https://doi.org/10.1051/0004-6361%2F201015637

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