A mechanism of helicity variations on the Sun |
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| Authors: | Benevolenskaya Elena E |
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| Institution: | (1) Pulkovo Astronomical Observatory, St. Petersburg, 196140, Russia |
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| Abstract: | Helicity of solar magnetic fields plays an important role in dynamo theories of the solar cycle. The helicity has been known to vary with the main 11-year period (Hale's cycle). Recent observations have revealed significant helicity variations on a shorter time scale, with a characteristic period of approximately 2 years. We suggest an explanation for the observed variations of the magnetic helicity, based on our model of the double magnetic cycle of solar activity. The quasi-biennial variations of the helicity are the consequence of the influence of erupted magnetic fields of the main cycle on the helicity in the regions of generation of the high-frequency component of magnetic field. This model suggests that the low-frequency component is generated at the base of the convective zone due to large-scale radial shear   /r of angular velocity . The high-frequency component may be generated in the subsurface region due to latitudinal shear / or due to the radial shear in this region. |
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