Title: Neutral Atom Diffusion in a Partially Ionized Prominence Plasma
Author: Holly R. Gilbert
Affil: HAO/NCAR
Email: iggy@ucar.edu
Authors: Viggo H. Hansteen, Thomas E. Holzer
Affils: Institute for Theoretical Astrophysics
Abstract: The support of solar prominences is normally described in terms of a magnetic force on the prominence plasma that balances the solar gravitational force. Because the prominence plasma is only partially ionized, it is necessary to consider in addition the support of the neutral component of the prominence plasma. This support is accomplished through a frictional interaction between the neutral and ionized components of the plasma, and its efficacy depends strongly on the degree of ionization of the plasma. More specifically, the frictional force is proportional to the relative flow of neutral and ion species, and for a sufficiently weakly ionized plasma, this flow must be relatively large to produce a frictional force that balances gravity. A large relative flow, of course, implies significant draining of neutral particles from the prominence. We evaluate the importance of this draining effect for a hydrogen-helium plasma, and consider the variation of the draining with the degree of heat input to the prominence plasma, which determines the ionization state of the prominence.