Thursday, April 26, 2012

1204.5532 (Kazunari Iwasaki et al.)

Structure of dynamical condensation fronts in the interstellar medium    [PDF]

Kazunari Iwasaki, Shu-ichiro Inutsuka
In this paper, we investigate the structure of condensation fronts from warm diffuse gas to cold neutral medium (CNM) under the plane parallel geometry. The solutions have two parameters, the pressure of the cold neutral medium (CNM) and the mass flux across the transition front and their ranges are much wider than previous thought. First, we consider the pressure range where the three phases, the CNM, the unstable phase, and the warm neutral medium, can coexist in the pressure equilibrium. In a wide range of the mass flux, we find solutions connecting the CNM and unstable phase. Moreover, we find solutions in larger pressure range where there is only one thermal equilibrium state, or the CNM. These solutions can be realized in shock-compressed regions that is promising sites of the molecular cloud formation. We also find remarkable properties in our solutions. The heat conduction becomes less important with increasing mass flux, and the thickness of the transition layer is characterized by the cooling length instead of the Field length.
View original: http://arxiv.org/abs/1204.5532

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