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Sheared helical turbulence and the helicity constraint in large-scale dynamos

A. Bigazzi·A. Brandenburg·K. Subramanian
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Abstract

The effect of shear on the growth of large scale magnetic fields in helical turbulence is investigated. The resulting large-scale magnetic field is also helical and continues to evolve, after saturation of the small scale field, on a slow resistive time scale. This is a consequence of magnetic helicity conservation. Because of shear, the time scale needed to reach an equipartition-strength large scale field is shortened proportionally to the ratio of the resulting toroidal to poloidal large scale fields.

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A. Bigazzi, A. Brandenburg, K. Subramanian. 2000-12-11. Sheared helical turbulence and the helicity constraint in large-scale dynamos. https://arxiv.org/abs/astro-ph/0012240

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