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Plasmatic Ionization in Stellar Nucleosynthesis

  1. Sep 11, 2014 #1
    So, I'm not a student in physics. Or astronomy. I'm actually a med student, just fairly curious.
    In stellar nucleosynthesis, plasma is required to fuse the particles from my understanding. In trying to record all the various reactions (PP Chain, Triple α Process, CNO Cycle), but I can't find how extreme this ionization is. Does it strip only the outer shell? Or are all of the electrons removed to allow fusion?
  2. jcsd
  3. Sep 11, 2014 #2


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    Deep inside the sun all electrons are stripped, particularly for light elements involved in fusion.
  4. Sep 11, 2014 #3
    Thanks! This implies answers to other questions I had too :) So does this apply to higher mass element burning as well? I mean, when lithium burns in brown dwarfs, the Li nucleus is free of electrons?
  5. Sep 11, 2014 #4


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    The core of the sun has a temperature of about 15 million K, which corresponds to an energy of about 1 keV. That is sufficient to ionize all light atoms. Stars that fuse heavier nuclei have an even higher temperature. In addition, the density is so high regular orbits (like for free atoms) wouldn't fit anyway.

    Not that it would matter - fusion is a pure nuclear process, and the nuclei don't care about the electrons (apart from the pep reaction of course).
  6. Sep 12, 2014 #5
    Plasma is not required.
    What is needed is some mechanism to allow the nuclei to meet each other in spite of Coulomb repulsion.

    This can be either thermal movement, or zero-point motion, or both.

    The matter is that sufficient thermal movement to allow nuclei to meet tends to excite electrons so much that they are not bound to and much concentrated around nuclei.

    But is cold and dense environment which is dense enough for appreciable pycnonuclear reactions a "plasma"?
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