Evaporation and Condensation of HI clouds in thermally bistable interstellar media: semi-analytic description of isobaric dynamics of curved interfaces

Abstract

We analyze the evaporation and condensation of spherical and cylindrical HI clouds of the cold neutral medium surrounded by the warm neutral medium. Because the interstellar medium including those two phases is well described as a thermally bistable fluid, it is useful to apply pattern formation theories to the dynamics of the interface between the two phases. Assuming isobaric evolution of fluids and a simple cubic form of the heat-loss function, we show the curvature effects of the interface. We find that approximate solutions for spherical clouds are in good agreement with numerically obtained solutions. We extend our analysis to general curved fronts taking into account the curvature effects explicitly. We find that the curvature effects always stabilise curved interfaces under assumptions such as isobaric evolution we adopt in this Letter.

arXiv comment5 pages, 4 figures, to appear in MNRAS Letters

References in corpus (9)

• Theory of Phase Ordering Kinetics
• The Neutral Atomic Phases of the ISM in the Galaxy
• An Origin of Supersonic Motions in Interstellar Clouds
• Thermal condensation in a turbulent atomic hydrogen flow
• Thermal Instability-Induced Interstellar Turbulence
• The Field Condition: A New Constraint of Spatial Resolution in Simulations of the nonlinear Development of Thermal Instability
• The nonlinear development of the thermal instability in the atomic ISM and its interaction with random fluctuations
• Dynamics of Conductive/Cooling Fronts: Cloud Implosion and Thermal Solitons
• Interstellar Phase Transitions Stimulated by Time-dependent Heating

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• How Long Can Tiny HI Clouds Survive?
• Self-Sustained Turbulence without Dynamical Forcing: A Two-Dimensional Study of a Bistable Interstellar Medium
• Structure of dynamical condensation fronts in the interstellar medium
• Extraordinary increase of lifetime of localized cold clouds by the viscous effect in thermally-unstable two-phase interstellar media
• Modeling the Accretion of High-Velocity Clouds from a Rotating Halo