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Magnetic fields on the Sun

  1. Feb 13, 2010 #1
    Pardon this completely naive question.

    I am wondering why there are net magnetic fields on the Sun. Isn't there an equal number of protons - hydrogen nuclei - to electrons? Is there a separation of protons and electrons in different parts of the Sun so that there can be net currents? or are magnetic fields fleeting and essentially random?
  2. jcsd
  3. Feb 14, 2010 #2
    The sun is, among other things, a giant EM Dynamo, just like the Earth's core in reation to mantle. The sun is of course, bigger, and better suited to such an application so HELLO Magnetic field! ;)
  4. Feb 15, 2010 #3
    After I read your reply I did a little reading on the web and got confused again.
    The articles say that shear forces between two of the sun's layers create the dynamo that you wrote about. How do shear forces create a dynamo?

    Also, in the Earth's core or in a conductor the currents come from free electrons in a conducting material. But on the Sun aren't there also free protons and wouldn't the proton generated magnetic fields tend to cancel the electron magnetic fields?
  5. Feb 16, 2010 #4
    You're absolutely right to be thinking about the total charge of a body being (mostly) canceled by other particles of opposite charges. It's that thinking that leads to the concept of a stellar dynamo in some ways. There simply is no way for a star to have the powerful magnetic field it clearly does caused by a glut of ions in the stellar body.

    Layers of gas, plasma, solids in the core, and fusing elements act like the liquid metallic layers of a moderm EM dynamo. How does that work? Well, the same for the sun as it does in a lab (in theory). http://en.wikipedia.org/wiki/Dynamo_theory

    Edit: Here is the underlying theory as applied to fluid (especially stellar fluid) dynamics. http://en.wikipedia.org/wiki/Magnetohydrodynamics Wiki does a shockingly good job on the first subject, and I'm no master of the second.
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