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Related papers: Linear Thermal Instability and Fluctuations in Mol…

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A systematic study of the linear thermal instability of a self-gravitating magnetic molecular cloud is carried out for the case when the unperturbed background is subject to local expansion or contraction. We consider the ambipolar…

Astrophysics · Physics 2009-11-11 Mohsen Nejad-Asghar , Jamshid Ghanbari

Thermal instability is one of the most important processes in the formation of clumpy substructure in magnetic molecular clouds. On the other hand, ambipolar diffusion, or ion-neutral friction, has long been thought to be an important…

Astrophysics · Physics 2009-11-10 Mohsen Nejad-Asghar , Jamshid Ghanbari

The low-mass condensations (LMCs) have been observed within the molecular cloud cores. In this research, we investigate the effect of isobaric thermal instability (TI) applied for forming these LMCs. For this purpose, at first we…

Astrophysics of Galaxies · Physics 2015-05-27 Mohsen Nejad-Asghar

We simulate fragmentation and gravitational collapse of cold, magnetized molecular clouds. We explore the nonlinear development of an instability mediated by ambipolar diffusion, in which the collapse rate is intermediate to fast…

Astrophysics · Physics 2009-10-31 R. Indebetouw , E. G. Zweibel

We study the linear evolution of small perturbations in self-gravitating fluid systems with magnetic fields. We consider wave-like perturbations to nonuniform filamentary and sheet-like hydrostatic equilibria in the presence of a uniform…

Astrophysics · Physics 2015-06-24 Curtis S. Gehman , Fred C. Adams , Richard Watkins

We investigate the propagation of a shock wave into a warm neutral medium and cold neutral medium by one-dimensional hydrodynamic calculations with detailed treatment of thermal and chemical processes. Our main result shows that thermal…

Astrophysics · Physics 2009-10-31 Hiroshi Koyama , Shu-Ichiro Inutsuka

We investigate the dynamical condensation process in a magnetized thermally bistable medium. We perform one-dimensional two fluid numerical simulations that describe the neutral and ionized components in the interstellar medium with purely…

Astrophysics · Physics 2009-11-11 Tsuyoshi Inoue , Shu-ichiro Inutsuka , Hiroshi Koyama

The thermal stability of rotating, stratified, unmagnetized atmospheres is studied by means of linear-perturbation analysis, finding stability, overstability or instability, depending on the properties of the gas distribution, but also on…

Astrophysics of Galaxies · Physics 2015-05-18 Carlo Nipoti

The radiative cooling of optically thin gaseous regions and the formation of a two-phase medium and of cold gas clouds with a clumpy substructure is investigated. In optically thin clouds, the growth rate of small isobaric density…

Astrophysics · Physics 2009-10-31 A. Burkert , D. N. C. Lin

Thermal fluctuations strongly modify the large length-scale elastic behavior of crosslinked membranes, giving rise to scale-dependent elastic moduli. While thermal effects in flat membranes are well understood, many natural and artificial…

Soft Condensed Matter · Physics 2013-02-19 Jayson Paulose , Gerard A. Vliegenthart , Gerhard Gompper , David R. Nelson

A long-standing question is whether radiative cooling can lead to local condensations of cold gas in the hot atmospheres of galaxies and galaxy clusters. We address this problem by studying the nature of local instabilities in rotating,…

Astrophysics of Galaxies · Physics 2015-06-19 Carlo Nipoti , Lorenzo Posti

We study magnetothermal instability in the ionized plasmas including the effects of Ohmic, ambipolar and Hall diffusion. Magnetic field in the single fluid approximation does not allow transverse thermal condensations, however, non-ideal…

Solar and Stellar Astrophysics · Physics 2014-11-20 Mohsen Shadmehri , Mohsen Nejad-Asghar , Alireza Khesali

Thermal instability (TI) is a trigger mechanism, which can explain the formation of small condensations through some regions of the interstellar clouds. The instability criterion for flat geometry approximations has been investigated in…

Astrophysics of Galaxies · Physics 2024-12-24 Mohsen Nejad-Asghar

A prevailing open problem in planetary nebulae research, and photoionized gaseous nebulae research at large, is the systematic discrepancies in electron temperatures and ionic abundances as derived from recombination and collisionally…

Solar and Stellar Astrophysics · Physics 2018-10-17 Manuel A. Bautista , Ehab E. Ahmed

In order to investigate the origin of the interstellar turbulence, detailed observations in the CO J=1--0 and 3--2 lines have been carried out in an interacting region of a molecular cloud with an HII region. As a result, several 1,000 to…

The frictional heating by ion-neutral drift is calculated and its effect on isobaric thermal instability is carried out. Ambipolar drift heating of one-dimensional self-gravitating magnetized molecular slab is used under the assumptions of…

Astrophysics · Physics 2009-06-23 M. Nejad-Asghar

We performed one-dimensional hydrodynamic simulations with detailed cooling, heating and chemical processes to examine the thermal stability of shocked gas in cold neutral medium (CNM) and molecular clouds. We find that both CNM and…

Solar and Stellar Astrophysics · Physics 2015-06-16 Takuhiro Aota , Tsuyoshi Inoue , Yuri Aikawa

All gasdynamical models for the evolution of gaseous content of galaxies assume that cooling from the hot, virialized phase to the cold phase occured through some sort of thermal instability. Subsequent formation of colder clouds embedded…

Astrophysics · Physics 2007-05-23 Milan M. Cirkovic

It is pointed out that electron thermal fluctuations can couple with the ion acoustic mode in an inhomogeneous plasma to generate a low frequency ion time scale electromagnetic wave. This electromagnetic wave can become unstable if the…

Plasma Physics · Physics 2015-05-13 Hamid Saleem

We present an investigation on effect of the ion-neutral (or ambipolar) diffusion heating rate on thermal phases of a molecular cloud. We use the modeling of ambipolar diffusion with two-fluid smoothed particle hydrodynamics, as discussed…

Astrophysics · Physics 2008-04-29 M. Nejad-Asghar , D. Molteni
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