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相关论文: Kinematics in Partially Ionised Molecular Clouds: …

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We present three numerical simulations of randomly driven, isothermal, non-magnetic, self-gravitating turbulence with different rms Mach numbers Ms and physical sizes L, but approximately the same value of the virial parameter, alpha approx…

Context: How do molecular clouds form out of the atomic phase? And what are the relative fractions of carbon in the ionized, atomic and molecular phase? These are questions at the heart of cloud and star formation. Methods: Using multiple…

太阳与恒星天体物理 · 物理学 2014-11-11 H. Beuther , S. E. Ragan , V. Ossenkopf , S. Glover , Th. Henning , H. Linz , M. Nielbock , O. Krause , J. Stutzki , P. Schilke , R. Guesten

Low-energy cosmic rays are a fundamental source of ionization for molecular clouds, influencing their chemical, thermal and dynamical evolution. The purpose of this work is to explore the possibility that a low-energy component of…

太阳与恒星天体物理 · 物理学 2015-05-13 Marco Padovani , Daniele Galli , Alfred E. Glassgold

We construct models of molecular clouds that are considered as ensembles of transient cores. Each core is assumed to develop in the background gas of the cloud, grow to high density and decay into the background. The chemistry in each core…

天体物理学 · 物理学 2009-11-13 R. T. Garrod , D. A. Williams , J. M. C. Rawlings

We investigate the low-frequency wave mode associated with heavy particles and its instability in a collisional complex plasma with drifting ions. The effect of the ion drift on the sound velocity of this mode is discussed. The general…

等离子体物理 · 物理学 2020-09-24 Sergey Khrapak , Victoria Yaroshenko

We utilize the extensive datasets available for the Perseus molecular cloud to analyze the relationship between the kinematics of small-scale dense cores and the larger structures in which they are embedded. The kinematic measures presented…

星系天体物理 · 物理学 2015-05-19 Helen Kirk , Jaime E. Pineda , Doug Johnstone , Alyssa Goodman

We investigate how neutral-ion collisional damping modifies the spectral properties and energy partition of compressible MHD turbulence using a suite of 3D two-fluid simulations. By systematically varying the neutral-ion coupling strength…

星系天体物理 · 物理学 2026-02-17 Yue Hu

Previous studies show that the physical structures and kinematics of a region depend significantly on the ionisation fraction. In this paper, we extend our previous studies of the effect of ionisation fractions on star formation to clouds…

太阳与恒星天体物理 · 物理学 2017-05-03 Nicole D. Bailey , Shantanu Basu , Paola Caselli

We investigate the nature of dissipative instability at the boundary (seen here as tangential discontinuity) between the viscous corona and the partially ionised prominence plasma in the incompressible limit. The importance of the partial…

太阳与恒星天体物理 · 物理学 2015-05-20 Istvan Ballai , Ramon Oliver , Marios Alexandrou

In this paper we present a numerical study of the dynamics of partially ionized coronal rain blobs. We use a two-fluid model to perform a high-resolution 2D simulation that takes into account the collisional interaction between the charged…

太阳与恒星天体物理 · 物理学 2022-12-07 David Martínez-Gómez , Ramón Oliver , Elena Khomenko , Manuel Collados

We summarize the current status of the turbulent model of star formation in turbulent molecular clouds. In this model, clouds, clumps and cores form a hierarchy of nested density fluctuations caused by the turbulence, and either collapse or…

天体物理学 · 物理学 2007-05-23 Enrique Vazquez-Semadeni

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…

天体物理学 · 物理学 2009-10-31 A. Burkert , D. N. C. Lin

Plasmoid-mediated fast magnetic reconnection plays a fundamental role in driving explosive dynamics and heating, but relatively little is known about how it develops in partially ionised plasmas (PIP) of the solar chromosphere. Partial…

等离子体物理 · 物理学 2024-06-19 Giulia Murtas , Andrew Hillier , Ben Snow

Cold dark matter haloes are populated by high-density structures with sharply-peaked profiles known as caustics which have not yet been resolved by 3-dimensional numerical simulations. Here, we derive semi-analytic expressions for the…

天体物理学 · 物理学 2009-11-10 Roya Mohayaee , Sergei Shandarin

(Abridged) We present a series of decaying turbulence simulations that represent a cluster-forming clump within a molecular cloud, investigating the role of magnetic fields on the formation of potential star-forming cores. We present an…

天体物理学 · 物理学 2007-11-07 David A. Tilley , Ralph E. Pudritz

Observations of atomic or molecular lines can provide important information about the physical state of star forming regions. In order to investigate the line profiles from dynamical collapsing massive star forming regions (MSFRs), we model…

星系天体物理 · 物理学 2015-06-15 Rowan J. Smith , Rahul Shetty , Henrik Beuther , Ralf S. Klessen , Ian A. Bonnell

We study the formation, evolution and collapse of dense cores by tracking structures in a magnetohydrodynamic simulation of a star-forming cloud. We identify cores using the dendrogram algorithm and utilize machine learning techniques,…

Shocks are a universal feature of the lower solar atmosphere which consists of both ionised and neutral species. Including partial ionisation leads to a finite-width existing for shocks, where the ionised and neutral species decouple and…

太阳与恒星天体物理 · 物理学 2021-01-20 B. Snow , A. Hillier

In this study we investigate the formation and properties of prestellar and protostellar cores using hydrodynamic, self-gravitating Adaptive Mesh Refinement simulations, comparing the cases where turbulence is continually driven and where…

天体物理学 · 物理学 2009-11-13 S. S. R. Offner , M. R. Krumholz , R. I. Klein , C. F. McKee

(Abridged) We present numerical hydrodynamical simulations of the formation, evolution and gravitational collapse of isothermal molecular cloud cores. A compressive wave is set up in a constant sub-Jeans density distribution of radius r = 1…