Alleviating alpha quenching by solar wind and meridional flows

作者：Mitra D^*; Moss D; Tavakol R; Brandenburg A

来源：Astronomy & Astrophysics, 2011, 526: A138.

DOI：10.1051/0004-6361/201015637

• Sun: dynamo
• magnetohydrodynamics (MHD)

Aims. We study the ability of magnetic helicity expulsion to alleviate catastrophic alpha-quenching in mean field dynamos in two-dimensional spherical wedge domains.
Methods. Motivated by the physical state of the outer regions of the Sun, we consider alpha(2)Omega mean field models with a dynamical a quenching. We include two mechanisms which have the potential to facilitate helicity expulsion, namely advection by a mean flow ("solar wind") and meridional circulation.
Results. 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.

• 出版日期2011-2