scholarly journals Helioseismic Observations of Solar Convection Zone Dynamics

2010 ◽  
Vol 6 (S271) ◽  
pp. 15-22
Author(s):  
Frank Hill ◽  
Rachel Howe ◽  
Rudi Komm ◽  
Irene González Hernández ◽  
Shukur Kholikov ◽  
...  
Keyword(s):  
Large Scale ◽  
Convection Zone ◽  
Global Analysis ◽  
Torsional Oscillation ◽  
Temporal Variations ◽  
Flare Activity ◽  
Flux Transport ◽  
Near Surface ◽  
Solar Convection Zone ◽  
Solar Convection

AbstractThe large-scale dynamics of the solar convection zone have been inferred using both global and local helioseismology applied to data from the Global Oscillation Network Group (GONG) and the Michelson Doppler Imager (MDI) on board SOHO. The global analysis has revealed temporal variations of the “torsional oscillation” zonal flow as a function of depth, which may be related to the properties of the solar cycle. The horizontal flow field as a function of heliographic position and depth can be derived from ring diagrams, and shows near-surface meridional flows that change over the activity cycle. Time-distance techniques can be used to infer the deep meridional flow, which is important for flux-transport dynamo models. Temporal variations of the vorticity can be used to investigate the production of flare activity. This paper summarizes the state of our knowledge in these areas.

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.

Large Scale Flows in the Solar Convection Zone

2008 ◽  
Vol 144 (1-4) ◽  
pp. 151-173 ◽  
Author(s):  
Allan Sacha Brun ◽  
Matthias Rempel
Keyword(s):  
Large Scale ◽  
Convection Zone ◽  
Solar Convection Zone ◽  
Solar Convection

Temporal Variation of Large Scale Flows in the Solar Interior

2000 ◽  
Vol 179 ◽  
pp. 353-356
Author(s):  
Sarbani Basu ◽  
H. M. Antia
Keyword(s):  
Large Scale ◽  
Outer Part ◽  
Temporal Variations ◽  
Solar Interior ◽  
Short Term ◽  
Measured Velocity ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Doppler Imager ◽  
Ring Diagram

AbstractWe attempt to detect short-term temporal variations in the rotation rate and other large scale velocity fields in the outer part of the solar convection zone using the ring diagram technique applied to Michelson Doppler Imager (MDI) data. The measured velocity field shows variations by about 10m/s on the scale of few days.

scholarly journals Helicity–vorticity turbulent pumping of magnetic fields in the solar dynamo

2012 ◽  
Vol 8 (S294) ◽  
pp. 367-368
Author(s):  
V. V. Pipin
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Differential Rotation ◽  
Large Scale ◽  
Convection Zone ◽  
Solar Dynamo ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Large Scale Magnetic Field ◽  
Convective Motions

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.

scholarly journals Large-scale flows and convection at the base of solar convection zone

2006 ◽  
Vol 2 (S239) ◽  
pp. 425-430
Author(s):  
Evgeniy Tikhomolov
Keyword(s):  
Magnetic Fields ◽  
Large Scale ◽  
Convection Zone ◽  
Three Dimensional ◽  
Solar Radius ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Rotation Periods ◽  
Scale Temperature ◽  
Local Sound

AbstractDevelopment of convection in sun's outer shell is caused by reduction of effectiveness of energy transfer by radiation. Traditionally, models of solar convection are considered to be axisymmetric on the scale of solar radius. Such models provide basic understanding of convection under solar conditions. However, interpretation of a number of observable large-scale long-lived solar phenomena requires developing a non-axisymmetric approach. We present such a model in which large-scale non-axisymmetry is caused by large-scale flows such as Rossby waves and vortices. We model flows near the base of the solar convection zone. Anelastic approximation is used, which is valid for flow velocities much smaller than local sound speed. Our three-dimensional numerical simulations show that interaction of convection with large-scale flows leads to the establishment of non-axisymmetric large-scale temperature distribution. The interaction also gives rise to large-scale variations of penetration depth of convective plumes. Generation of the magnetic field by large-scale non-axisymmetric flows can explain such solar phenomena as complexes of activity, active longitudes, drifts of large-scale magnetic fields from equator to the poles, and appearance of distinct rotation periods of magnetic fields at some latitudes. We discuss a possibility of detection of large-scale non-axisymmetric flows and temperature distributions associated with them by the methods of helioseismology.

scholarly journals Search for Giant Cells in the Solar Convection Zone

1980 ◽  
Vol 91 ◽  
pp. 21-23 ◽  
Author(s):  
B. J. Labonte ◽  
R. Howard
Keyword(s):  
Large Scale ◽  
Convection Zone ◽  
Solar Rotation ◽  
Longitudinal Velocity ◽  
Giant Cells ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Mount Wilson Observatory ◽  
Entire Dataset ◽  
Full Disk

The Mount Wilson Observatory has obtained daily full disk digital magnetograms of the Sun since 1966, with 12 to 17 arcsecond resolution. As each magnetogram is taken, the position of the Doppler line shift compensator is also recorded, thus giving a full disk map of the longitudinal velocity. This entire dataset is currently being rereduced on a uniform basis (Howard et al., 1980), and daily arrays of residual velocities are being formed by removing large scale patterns, e.g., Earth's motions, solar rotation, limbshift. Data from the years 1972 through 1978 are used here.

scholarly journals Helioseismic inferences on subsurface solar convection

2006 ◽  
Vol 2 (S239) ◽  
pp. 113-121
Author(s):  
Alexander G. Kosovichev
Keyword(s):  
Large Scale ◽  
Meridional Flow ◽  
Polar Regions ◽  
Flux Transport ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
New Methods ◽  
Global Properties ◽  
The Mean ◽  
Depth Stratification

AbstractHelioseismology has provided robust estimates of global properties of the solar convection zone, its depth, stratification, and revealed rotational shear layers at the boundaries. New methods of local helioseismology provide 3D maps of subsurface convective flows. In the quiet Sun regions, these maps reveal that supergranular-scale convection extends to the depth of 12–15 Mm. Analysis of evolution of the supergranular convection pattern shows evidence for a wave-like behavior which might be related to the interaction between convection and the subsurface rotational sheer layer. Helioseismology also reveals large-scale circulation flows around magnetic regions. These flows affect the evolution of the mean meridional flow during the solar cycle and, probably, the magnetic flux transport from mid-latitudes to the polar regions, a process important for solar dynamo theories. Helioseismic measurements on a smaller scale, below sunspots, give insight on how convection interacts with strong magnetic fields.

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.

Sign in / Sign up

Export Citation Format

Share Document