English

Are Neutral Sunspot Winds Important for Penumbral Dynamics and the First Ionization Potential Effect?

Astrophysics 2016-08-30 v1

Abstract

The low ionization state in parts of a sunspot may play an important role in its evolution and dynamical state. The cool magnetic interior region of the sunspot develops a substantial neutral atomic and molecular hydrogen osmotic pressure which can drive a wind outward from the umbra. Ambipolar diffusion against the magnetically pinned ionized plasma component can also distort the umbral magnetic field into a filamentary penumbral structure. This may be important for explaining the development of the sunspot penumbra and the Evershed flow. This fractionation process may also be important for the ``First Ionization Potential'' (FIP) effect seen in the solar wind. In support of this mechanism we find evidence for such ionization fractionization in UV observations of molecular hydrogen in a sunspot umbra and penumbra.

Keywords

Cite

@article{arxiv.astro-ph/0509862,
  title  = {Are Neutral Sunspot Winds Important for Penumbral Dynamics and the First Ionization Potential Effect?},
  author = {J. R. Kuhn and H. Lin and H. Morgan},
  journal= {arXiv preprint arXiv:astro-ph/0509862},
  year   = {2016}
}

Comments

4 pages, ApJL format (submitted, in revision)