An ionization-coupled acoustic instability of the interstellar medium

Abstract

view Abstract Citations (23) References (11) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS An ionization-coupled acoustic instability of the interstellar medium. Flannery, B. P. ; Press, W. H. Abstract A simple set of equations is formulated to represent cold interstellar clouds, and a linear stability analysis is preformed for this model. The model is characterized by a quartic dispersion relation whose coefficients depend only on two nondimensional parameters; the criterion for acoustic instability and the resulting growth rates and mass scales associated with the most unstable modes are computed as functions of these two dimensionless parameters, which are characteristic of the equilibrium state. The results are applied to the physics of the interstellar medium, first for a simple model and then for a more complex equation of state. Both calculations indicate that thermally stable cold clouds with temperatures between 30 and 90 K are acoustically unstable. The fate of a cloud after the instability goes nonlinearly to completion is considered, along with the relevance of the acoustic instability to star formation. Publication: The Astrophysical Journal Pub Date: August 1979 DOI: 10.1086/157233 Bibcode: 1979ApJ...231..688F Keywords: Acoustic Instability; Cosmic Rays; Interstellar Matter; Ionization; Mathematical Models; Equations Of State; Hydrodynamic Equations; Thermodynamic Equilibrium; Ultraviolet Radiation; Astrophysics; Cosmic Rays:Interstellar Matter; Interstellar Matter:Stability full text sources ADS |