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Related papers: A Super-Alfvenic Model of Dark Clouds

200 papers

In this work, we present the mass and magnetic distributions found in a recent Adaptive Mesh Refinement (AMR) MHD simulation of supersonic, \sa, self gravitating turbulence. Powerlaw tails are found in both volume density and magnetic field…

Astrophysics of Galaxies · Physics 2015-05-19 David C. Collins , Paolo Padoan , Michael L. Norman , Hao Xu

We have computed line emission cooling rates for the main cooling species in models of interstellar molecular clouds. The models are based on numerical simulations of super-sonic magneto-hydrodynamic (MHD) turbulence. Non-LTE radiative…

Astrophysics · Physics 2009-11-06 M. Juvela , P. Padoan , A Nordlund

Using self-consistent magnetohydrodynamic (MHD) simulations, we explore the hypothesis that nonlinear MHD waves dominate the internal dynamics of galactic molecular clouds. We employ an isothermal equation of state and allow for…

Astrophysics · Physics 2016-08-30 Charles F. Gammie , Eve C. Ostriker

Turbulence and magnetic fields are components of the interstellar medium and are interconnected through plasma processes. In particular, the magnetic flux transport in the presence of magneto-hydrodynamic (MHD) turbulence is an essential…

High Energy Astrophysical Phenomena · Physics 2025-07-30 C. N. Koshikumo , R. Santos-Lima , M. V. del Valle , E. M. de Gouveia Dal Pino , G. Guerrero , A. Lazarian

The presence of dust grains profoundly affects the diffusion of the magnetic field in molecular clouds. When the electrons and ions are well coupled to the magnetic field and charged grains are only indirectly coupled, emergent Hall…

Astrophysics of Galaxies · Physics 2019-02-13 B. P. Pandey , S. V. Vladimirov

We have carried out an extensive survey of magnetic field strengths toward dark cloud cores in order to test models of star formation: ambipolar-diffusion driven or turbulence driven. The survey involved $\sim500$ hours of observing with…

Astrophysics · Physics 2009-11-13 Thomas H. Troland , Richard M. Crutcher

Recent observations of column densities in molecular clouds find lognormal distributions with power-law high-density tails. These results are often interpreted as indications that supersonic turbulence dominates the dynamics of the observed…

Astrophysics of Galaxies · Physics 2015-05-19 K. Tassis , D. A. Christie , A. Urban , J. L. Pineda , T. Ch. Mouschovias , H. W. Yorke , H. Martel

We perform ideal MHD high resolution AMR simulations with driven turbulence and self-gravity and find that long filamentary molecular clouds are formed at the converging locations of large-scale turbulence flows and the filaments are…

Astrophysics of Galaxies · Physics 2019-04-10 Pak Shing Li , Richard I. Klein

Intercluster medium is expected to be turbulent with turbulence being superAlfvenic at large scales. Magnetic fields substantially modify the turbulent cascade when the turbulence reaches the scales at which the fluctuation velocity gets…

Astrophysics · Physics 2009-11-11 A. Lazarian

We investigate the physical properties of dense cores formed in turbulent, magnetized, parsec-scale clumps of molecular clouds, using three-dimensional numerical simulations that include protostellar outflow feedback. The dense cores are…

Solar and Stellar Astrophysics · Physics 2015-05-28 Fumitaka Nakamura , Zhi-Yun Li

We study the magnetic field to density ($B-\rho$) relation in turbulent molecular clouds with dynamically important magnetic fields using nonideal three-dimensional magnetohydrodynamic simulations. Our simulations show that there is a…

Astrophysics of Galaxies · Physics 2022-03-30 Sayantan Auddy , Shantanu Basu , Takahiro Kudoh

The conversion of fast waves to the Alfven mode in a realistic sunspot atmosphere is studied through three-dimensional numerical simulations. An upward propagating fast acoustic wave is excited in the high-beta region of the model. The new…

Solar and Stellar Astrophysics · Physics 2015-06-11 T. Felipe

We investigate the formation of molecular clouds from atomic gas by using three-dimensional magnetohydrodynamical simulations,including non-equilibrium chemical reactions, heating/cooling processes, and self-gravity by changing the…

Astrophysics of Galaxies · Physics 2022-08-17 Kazunari Iwasaki , Kengo Tomida

Modeling the structure of molecular clouds depends on good methods to statistically compare simulations with observations in order to constrain the models. Here we characterize a suite of hydrodynamical and magnetohydrodynamical (MHD)…

Astrophysics · Physics 2007-05-23 Mordecai-Mark Mac Low , Volker Ossenkopf

Super-sonic turbulence fragments molecular clouds (MC) into a very complex density field with density contrasts of several orders of magnitude. A fraction of the gas is locked into dense and gravitationally bound cores, which collapse as…

Astrophysics · Physics 2007-05-23 Paolo Padoan , AAke Nordlund , Ornolfur Einar Rognvaldsson , Alyssa Goodman

The strengths of magnetic fields in interstellar gas clouds are obtained through observations of the circular polarization of spectral line radiation. Irregularities in this magnetic field may be present due to turbulence, waves or perhaps…

Astrophysics · Physics 2009-10-31 W. D. Watson , D. S. Wiebe , R. M. Crutcher

We study the conversion of fast magneto-acoustic waves to Alfven waves by means of 2.5D numerical simulations in a sunspot-like magnetic configuration. A fast, essentially acoustic, wave of a given frequency and wave number is generated…

Solar and Stellar Astrophysics · Physics 2015-06-03 Elena Khomenko , Paul Cally

Generation of wave structures by a two-dimensional object (laser beam) moving in a two-dimensional two-component Bose-Einstein condensate with a velocity greater than both sound velocities of the mixture is studied by means of analytical…

Other Condensed Matter · Physics 2009-11-13 Yu. G. Gladush , A. M. Kamchatnov , Z. Shi , P. G. Kevrekidis , D. J. Frantzeskakis , B. A. Malomed

Galactic winds probe how stellar feedback regulates the mass and metallicity of galaxies. Observations show that galactic winds are multiphase and magnetised. In the local Universe, the dense phase is traced by emission and absorption…

Observations indicate that molecular clouds are strongly magnetized, and that magnetic fields influence the formation of stars. A key observation supporting the conclusion that molecular clouds are significantly magnetized is that the…