Sun  ID: 3521

The Solar Dynamo: Toroidal and Poloidal Magnetic Fields

Using the solar plasma flows as input (see The Solar Dynamo: Plasma Flows), the equations of magnetohydrodynamics, and 'seeding' the calculations with an initial small magnetic field, one can compute how a magnetic field can grow and be maintained. This is the dynamo process, the net result being that part of the Sun's outflowing thermal convective energy from nuclear processes is used to create the magnetic field.

In this view of the solar dynamo mechanism, we examine the evolution of the toroidal magnetic field, the field intensity represented by colors on the right-hand cross-section, and the poloidal magnetic potential field, represented by colors on the left-hand cross-section. The poloidal magnetic potential is a scalar quantity that contains information about the radial and latitudinal magnetic field vectors. To see the radial magnetic field, see The Solar Dynamo: Toroidal and Radial Magnetic Fields.

In this visualization, the magnetic field lines (represented by the 'copper wire' structures) are 'snapshots' of the field structure constructed at each time step of the model. These field lines should not be considered as 'moving' or 'stretching' as the model evolves in time.

Even this simplified model reproduces a number of characteristics observed in the actual solar magnetic field.

  1. Cyclic behavior with oscillations in the magnetic field amplitude.
  2. Magnetic regions at the surface migrate from high latitudes towards the equator as the solar cycle progresses. This reproduces the "Butterfly Diagram" pattern.
  3. Surface magnetic polarities reverse with each cycle

Because this model is axisymmetric, it cannot simulate non-axisymmetric features such as active longitudes.


Used Elsewhere In


Visualization Credits

Tom Bridgman (GST): Lead Animator
Andres Munoz-Jaramillo (Montana State University): Scientist
Dibyendu Nandi (Indian Institute of Science Education and Research, Kolkata): Scientist
William D. Pesnell (NASA/GSFC): Scientist
Petrus C. H. Martens (Harvard Smithsonian Center for Astrophysics): Scientist
Please give credit for this item to:
NASA/Goddard Space Flight Center Scientific Visualization Studio

Science Paper:
Helioseismic Data Inclusion in Solar Dynamo Models

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Data Used:
SOHO/Michelson Doppler Interferometer (MDI)/Continuum May 1996 to February 2009
Note: While we identify the data sets used in these visualizations, we do not store any further details nor the data sets themselves on our site.

This item is part of these series:
SDO Pre-launch
Solar Dynamo
SDO - Visualizations

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GCMD keywords can be found on the Internet with the following citation: Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version