Alfvén ionization in the atmospheres of brown dwarfs

Stark, C.R. , Helling, C., Diver, D.A. and Rimmer, P.B. (2013) Alfvén ionization in the atmospheres of brown dwarfs. Societa Astronomica Italiana, Memorie, 84, p. 1132.

Abstract

Ionization processes and the generation of plasmas are critical elements in a holistic understanding of substellar atmospheres. We propose Alfvén ionization as a mechanism for producing localized pockets of ionized gas in the atmosphere, having sufficient degrees of ionization (>10-7) that they constitute plasmas. This paper outlines the criteria required for Alfvén ionization to occur and demonstrate its applicability in Brown Dwarf atmospheres. Our results show that degrees of ionization ranging from 10-6-1 can be obtained. Furthermore, Alfvén ionization alters the atmospheric chemistry via the creation of new ionic species not normally available in contemporary, thermally-driven atmospheric models. Observable consequences include continuum Bremsstrahlung emission superimposed with spectral lines from the plasma ion species. The presence of an atmospheric plasma opens the door to a multitude of plasma and chemical processes not yet considered in current atmospheric models.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Diver, Professor Declan and Stark, Mr Craig
• Authors: Stark, C.R., Helling, C., Diver, D.A., and Rimmer, P.B.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Societa Astronomica Italiana, Memorie
• ISSN: 0037-8720
• ISSN (Online): 1824-016X