Generation of the radial magnetic field of the Sun by global hydrodynamic flows

1Loginov, AA, 2Krivodubskij, VN, 1Cheremnykh, OK
1Space Research Institute under NAS and National Space Agency of Ukraine, Kyiv, Ukraine
2Astronomical Observatory of Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
Kinemat. fiz. nebesnyh tel (Online) 2020, 36(2):20-33
Start Page: Solar Physics
Language: Ukrainian

The concept of the emergence of global hydrodynamic flows of matter and the generation of global magnetic fields in the solar convective zone is proposed, in which the unstable profile of differential rotation plays a leading role. Due to the loss of stability of the differential rotation, all hydrodynamic flows on the Sun are generated: poloidal circulation, torsion oscillations and spatio-temporal variations of the poloidal flow. A similar result was not obtained in any of the models known to us, in which, as a rule, torsion oscillations and variations of the meridional circulation are calculated separately and therefore they are considered independent flows. In contrast, the calculations carried out within the framework of our model allow us to state that the indicated flows actually serve as toroidal and poloidal components of a single 3-dimensional global flow. In this work, we have demonstrated the decisive role of torsion oscillations in the generation of a radial alternating magnetic field. As a result of numerical simulation, it was found that the time-varying radial magnetic field on the surface of the Sun reaches its maximum value at the poles, where it changes its polarity with a period of about 22 years. This process can be identified with the observed effect of the polarity reversal of the polar field during the Hale magnetic cycle. It was found that the lines of zero values (polarity reversal) of the surface radial magnetic field pass along the maxima of the magnitude of the velocity modulus of zonal flows (torsion oscillations). In this case, the lines of change in the magnetic polarity of the radial field and the maximum velocities of the surface zonal flows drift from the poles to the equator. It was noted that our results on the latitudinal evolution of surface zonal flows correlate with the behavior of deep zonal flows obtained as a result of processing helioseismological data.

Keywords: global hydrodynamic flows, magnetic fields, numerical simulation, solar convection zone

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