scholarly journals Large-Scale Magnetic Field Fragmentation in Flux-Tubes Near the Base of the Solar Convection Zone

2019 ◽  
Vol 45 (1) ◽  
pp. 39-48 ◽  
Author(s):  
L. L. Kitchatinov
2012 ◽  
Vol 8 (S294) ◽  
pp. 367-368
Author(s):  
V. V. Pipin

AbstractThe interaction of helical convective motions and differential rotation in the solar convection zone results in turbulent drift of a large-scale magnetic field. We discuss the pumping mechanism and its impact on the solar dynamo.


1993 ◽  
Vol 157 ◽  
pp. 49-50
Author(s):  
V.N. Krivodubskij

The mean magnetic field transport due to inhomogeneity of the turbulence intensity is considered taking the field back reaction on motion into account. In spite of the magnetic quenching, the downward diamagnetic pumping is still powerful enough to keep the fields of 3 to 4 kG strength near the SCZ base against the magnetic buoyancy.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Yuhong Fan

AbstractIt has been a prevailing picture that active regions on the solar surface originate from a strong toroidal magnetic field stored in the overshoot region at the base of the solar convection zone, generated by a deep seated solar dynamo mechanism. This article reviews the studies in regard to how the toroidal magnetic field can destabilize and rise through the convection zone to form the observed solar active regions at the surface. Furthermore, new results from the global simulations of the convective dynamos, and from the near-surface layer simulations of active region formation, together with helioseismic investigations of the pre-emergence active regions, are calling into question the picture of active regions as buoyantly rising flux tubes originating from the bottom of the convection zone. This article also gives a review on these new developments.


2001 ◽  
Vol 203 ◽  
pp. 273-275
Author(s):  
Y. Fan

Solar active regions are believed to correspond to the topmost portions of Ω-shaped arching flux tubes that have risen buoyantly from the base of the solar convection zone, where strong toroidal magnetic fields are being generated by the dynamo process. The development of such emerging Ω-loops is likely a result of the buoyant instability associated with the submerged toroidal magnetic field. Using an anelastic MHD code, we simulate the formation of buoyant, arching flux tube structures as a result of the non-linear growth of the undular instability of a neutrally buoyant layer of horizontal, unidirectional magnetic field at the base of the solar convection zone.


2006 ◽  
Vol 2 (S239) ◽  
pp. 502-504
Author(s):  
Valery N. Krivodubskij

AbstractThis investigation is devoted to study the turbulent convective transport of mean (large-scale) magnetic field in the solar convection zone (SCZ). For the SCZ model by Stix (1989) the reconstruction of the toroidal field was calculated as a result of the balance of mean-field magnetic buoyancy and two “negative magnetic buoyancy” effects: i) macroscopic turbulent diamagnetism and ii) the ∇ρ effect. It is shown that at high latitudes negative buoyancy effects block the magnetic fields, about 3000 – 4000 G, near the bottom of the SCZ. This may be the most plausible reason why a deep-seated field here could not become as apparent at the solar surface as sunspots. However, at the near equatorial domain in the deep layers the ∇ρ effect, with allowance for rotation, causes the upward magnetic transport, that facilitates penetration of strong fields to the surface where they emerge as sunspot patters in the “royal zone”.


2010 ◽  
Vol 6 (S271) ◽  
pp. 288-296
Author(s):  
Laurène Jouve ◽  
Michael R. E. Proctor ◽  
Geoffroy Lesur

AbstractWe present the effects of introducing results of 3D MHD simulations of buoyant magnetic fields in the solar convection zone in 2D mean-field Babcock-Leighton models. In particular, we take into account the time delay introduced by the rise time of the toroidal structures from the base of the convection zone to the solar surface. We find that the delays produce large temporal modulation of the cycle amplitude even when strong and thus rapidly rising flux tubes are considered. The study of a reduced model reveals that aperiodic modulations of the solar cycle appear after a sequence of period doubling bifurcations typical of non-linear systems. We also discuss the memory of such systems and the conclusions which may be drawn concerning the actual solar cycle variability.


2011 ◽  
Vol 7 (S286) ◽  
pp. 154-158 ◽  
Author(s):  
J. Warnecke ◽  
P. J. Käpylä ◽  
M. J. Mantere ◽  
A. Brandenburg

AbstractWe present a three-dimensional model of rotating convection combined with a simplified model of a corona in spherical coordinates. The motions in the convection zone generate a large-scale magnetic field which is sporadically ejected into the outer layers above. Our model corona is approximately isothermal, but it includes density stratification due to gravity.


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