scholarly journals Magnetic fields in the solar convection zone

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Yuhong Fan
Keyword(s):  
Magnetic Field ◽  
Convection Zone ◽  
Active Regions ◽  
Toroidal Magnetic Field ◽  
Near Surface ◽  
New Developments ◽  
Solar Convection Zone ◽  
Flux Tubes ◽  
Solar Convection ◽  
Dynamo Mechanism

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.

scholarly journals Formation of Arching Flux Tubes at the Base of the Solar Convection Zone

2001 ◽  
Vol 203 ◽  
pp. 273-275
Author(s):  
Y. Fan
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Linear Growth ◽  
Convection Zone ◽  
Active Regions ◽  
Solar Convection Zone ◽  
Flux Tubes ◽  
Solar Convection ◽  
Neutrally Buoyant ◽  
Dynamo Process

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.

scholarly journals Can short time delays influence the variability of the solar cycle?

2010 ◽  
Vol 6 (S271) ◽  
pp. 288-296
Author(s):  
Laurène Jouve ◽  
Michael R. E. Proctor ◽  
Geoffroy Lesur
Keyword(s):  
Solar Cycle ◽  
Convection Zone ◽  
Mean Field ◽  
Period Doubling ◽  
Temporal Modulation ◽  
Solar Convection Zone ◽  
Flux Tubes ◽  
Solar Convection ◽  
Short Time ◽  
Period Doubling Bifurcations

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.

scholarly journals Weak influence of near-surface layer on solar deep convection zone revealed by comprehensive simulation from base to surface

2019 ◽  
Vol 5 (1) ◽  
pp. eaau2307 ◽  
Author(s):  
H. Hotta ◽  
H. Iijima ◽  
K. Kusano
Keyword(s):  
Convection Zone ◽  
Solar Surface ◽  
Deep Convection ◽  
Surface Region ◽  
Local Domain ◽  
Near Surface ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Weak Influence ◽  
The Magnetic Field

The solar convection zone is filled with turbulent convection in highly stratified plasma. Several theoretical and observational studies suggest that the numerical calculations overestimate the convection velocity. Since all deep convection zone calculations exclude the solar surface due to substantial temporal and spatial scale separations, the solar surface, which drives the thermal convection with efficient radiative cooling, has been thought to be the key to solve this discrepancy. Thanks to the recent development in massive supercomputers, we are successful in performing the comprehensive calculation covering the whole solar convection zone. We compare the results with and without the solar surface in the local domain and without the surface in the full sphere. The calculations do not include the rotation and the magnetic field. The surface region has an unexpectedly weak influence on the deep convection zone. We find that just including the solar surface cannot solve the problem.

Emerging Flux Tubes in the Solar Convection Zone. II. The Influence of Initial Conditions

1998 ◽  
Vol 502 (1) ◽  
pp. 481-492 ◽  
Author(s):  
P. Caligari ◽  
M. Schussler ◽  
F. Moreno‐Insertis
Keyword(s):  
Convection Zone ◽  
Initial Conditions ◽  
Solar Convection Zone ◽  
Flux Tubes ◽  
Solar Convection ◽  
Zone Ii

scholarly journals The Rise of Kink-Unstable Magnetic Flux Tubes in the Solar Convection Zone

1998 ◽  
Vol 505 (1) ◽  
pp. L59-L63 ◽  
Author(s):  
Y. Fan ◽  
E. G. Zweibel ◽  
M. G. Linton ◽  
G. H. Fisher
Keyword(s):  
Magnetic Flux ◽  
Convection Zone ◽  
Solar Convection Zone ◽  
Flux Tubes ◽  
Solar Convection ◽  
Magnetic Flux Tubes
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