Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Energy flux in sun gives rise to polarization of plasma in sun?

  1. Oct 17, 2009 #1
    In the energy producing region of the sun there is a large radial flux of high energy photons. Does this outward flux polarize the plasma and give rise to a electric field in this inner region? What is an order of magnitude estimate of this field?

    As the sun rotates this field gives rise to a magnetic field?

    Thanks for your thoughts.
  2. jcsd
  3. Oct 19, 2009 #2
    In the Klein–Nishina formula, see:


    the differential cross section for the scattering of photons from electrons goes as 1/(m_e)^2

    If we substituted the mass of a proton the scattering is reduced by a factor of roughly 1/2000^2

    Can we use this fact to show that the large radial energy flux in the sun will tend to polarize the plasma in the radiation zone of the sun?

    Thanks for any thoughts.
  4. Oct 19, 2009 #3
    I do know that for most of the life of a star it's thermonuclear fusion powering things.
    My guess is that convection, conduction and radiation all carry energy ...here is a blurb from wikipedia to consider:


    (my boldface highlight)

    There are other pieces in the main article that may be of interest to you. They lead me to question the accuracy your post but don't take this as authoratative.....just a personal comment. They may lead you to other areas of inquiry.
    good luck.
  5. Oct 20, 2009 #4
    Somewhere I read, if my memory is correct, that if the sun had a small initial "seed" magnetic field that the dynamics of the sun would take care of turning that seed field into a larger dynamic magnetic field.

    I thought I had a possible source for that seed field. I'm stumped how to even get some order of magnitude estimate using the fact(?) that the cross-section for photons to scatter off electrons is greater then the cross-section for photons to scatter off positive matter in the sun which should(?) give rise to polarization of charge and if the sun does not rotate as a whole movement relative to this polarized charge would give rise to a magnetic field?

    We know the energy output of the sun and have estimates for the pressure, density, and temperature as functions of the distance from the center of the sun. How would you get an order of magnitude estimate for this supposed polarization.

    Thanks for your thoughts.
  6. Oct 20, 2009 #5
    My basic, and limited understanding of plasma physics was confirmed by the following Wikipedia quote:

    So my instinct is confirmed that once heat rises to a certain level, be it by gravitational attractive energy or nuclear fusion or both, you could hardly stop ionization of hydrogen gas (and typically some helium) and the creation of a plasma even if you wanted to...maybe that's what you mean by a "seed" but my own take is that no seed is necessary...once a gas temperature rises to a high enough level, neutrinos, protons, electrons and everything imagniable begins to "boil" off and electromagnetic fields result. And with the typical rotation of a star, different portions of the plasma are likely accelerated relative to each other even more and stronger electromagnetic fields are inevitable...

    I've never even seen any descriptive mathematics for plasma fields but maybe you can search ARXIV.....
    Last edited: Oct 20, 2009
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook