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Related papers: Long-lived Magnetic-Tension-Driven Modes in a Mole…

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Accretion disks are likely threaded by external vertical magnetic flux, which enhances the level of turbulence via the magnetorotational instability (MRI). Using shearing-box simulations, we find that such external magnetic flux also…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Xue-Ning Bai , James M. Stone

The magnetic field strength in molecular clouds is a fundamental quantity for theories of star formation. It is estimated by Zeeman splitting measurements in a few dense molecular cores, but its volume--averaged value within large molecular…

Astrophysics · Physics 2009-11-10 Paolo Padoan , Raul Jimenez , Mika Juvela , Aake Nordlund

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

We report the observations of the magneto-hydrodynamic waves propagating along magnetic flux tubes in the solar photosphere. We identified 20 isolated strong peaks (8 peaks for pores and 12 peaks for inter-granular magnetic structure) in…

Solar and Stellar Astrophysics · Physics 2015-05-13 Daisuke Fujimura , Saku Tsuneta

Within the last decade, due to significant improvements in the spatial and temporal resolution of chromospheric data, magnetohydrodynamic (MHD) wave studies in this fascinating region of the Sun's atmosphere have risen to the forefront of…

Solar and Stellar Astrophysics · Physics 2016-03-09 G. Verth , D. B. Jess

This is the first paper about the fragmentation and mass outflow in the molecular cloud by using three-dimensional MHD nested-grid simulations. The binary star formation process is studied paying particular attention to the fragmentation of…

Astrophysics · Physics 2009-11-10 Masahiro N Machida , Kohji Tomisaka , Tomoaki Matsumoto

Numerical simulations of dispersive turbulence in magnetized plasmas based on the Hall-MHD description are presented, assuming spatial variations along a unique direction making a prescribed angle with the ambient magnetic field. Main…

Earth and Planetary Astrophysics · Physics 2015-05-18 D. Laveder , L. Marradi , T. Passot , P. L. Sulem

We present results of non-linear, 2D, numerical simulations of magneto-acoustic wave propagation in the photosphere and chromosphere of small-scale flux tubes with internal structure. Waves with realistic periods of three to five minutes…

Astrophysics · Physics 2009-11-13 E. Khomenko , M. Collados , T. Felipe

We employ the first fully three-dimensional simulation to study the role of magnetic fields and ion-neutral friction in regulating gravitationally-driven fragmentation of molecular clouds. The cores in an initially subcritical cloud develop…

Astrophysics · Physics 2008-11-26 Takahiro Kudoh , Shantanu Basu , Youichi Ogata , Takashi Yabe

Oscillations in coronal loops are usually interpreted in terms of uncoupled magnetohydrodynamic (MHD) waves. Examples of these waves are standing transverse motions, interpreted as the kink MHD modes, and propagating slow modes, commonly…

Solar and Stellar Astrophysics · Physics 2015-05-20 J. Terradas , J. Andries , E. Verwichte

The interstellar turbulence is magnetized and thus anisotropic. The anisotropy of turbulent magnetic fields and velocities is imprinted in the related observables, rotation measures (RMs), and velocity centroids (VCs). This anisotropy…

Astrophysics of Galaxies · Physics 2021-04-07 Siyao Xu , Yue Hu

We study the properties of sub-Alfvenic magnetohydrodynamic (MHD) turbulence, i.e., turbulence with Alfven Mach number $M_A=V_L/V_A<1$, where $V_L$ is the velocity at the injection scale and $V_A$ is the Alfven velocity. We demonstrate that…

Astrophysics of Galaxies · Physics 2024-10-28 Alex Lazarian , Ka Wai HO , Ka Ho Yuen , Ethan Vishniac

An enhancement in high-frequency acoustic power is commonly observed in the solar photosphere and chromosphere surrounding magnetic active regions. We perform 3D linear forward wave modelling with a simple wavelet pulse acoustic source to…

Solar and Stellar Astrophysics · Physics 2015-06-23 Carlos Rijs , Hamed Moradi , Damien Przybylski , Paul S. Cally

When cool clouds are ram-pressure accelerated by a hot supersonic galactic wind, some of the clouds may be shredded by hydrodynamical instabilities and incorporated into the hot flow. Recent one-dimensional steady-state calculations show…

Astrophysics of Galaxies · Physics 2023-07-25 Dustin D. Nguyen , Todd A. Thompson , Evan E. Schneider , Ashley P. Tarrant

Shock waves are simulated passing through the Alfv\'en-acoustic equipartition layer in a stratified isothermal magneto-atmosphere. The recent ray-theoretic calculations of N\'u\~nez (2019) predicted smoothing of the shock through this…

Solar and Stellar Astrophysics · Physics 2019-08-21 Jamon D. Pennicott , Paul S. Cally

We perform three-dimensional (3D) compressible MHD simulations over many dynamical times for an extended range of sonic and Alfven Mach numbers and analyze the statistics of 3D density and 2D column density, which include probability…

Astrophysics · Physics 2009-01-19 G. Kowal , A. Lazarian , A. Beresnyak

MHD wave propagation inside the Sun's atmosphere is closely related to the magnetic field topology. For example, magnetic fields are able to lower the cutoff frequency for acoustic waves thus allowing waves which would otherwise be trapped…

Solar and Stellar Astrophysics · Physics 2015-05-30 M. Stangalini , D. Del Moro , F. Berrilli , S. M. Jefferies

Small-scale magnetic fields are thought to play an important role in the heating of the outer solar atmosphere. By taking advantage of the unprecedented high-spatial and temporal cadence of IMaX, the filter vector polarimeter on board the…

Solar and Stellar Astrophysics · Physics 2015-06-15 M. Stangalini , S. K. Solanki , R. Cameron , V. Martìnez Pillet

We use a set of magnetohydrodynamics (MHD) simulations of fully-developed (driven) turbulence to study the anisotropy in the velocity field that is induced by the presence of the magnetic field. In our models we study turbulence…

Astrophysics of Galaxies · Physics 2015-05-30 Alejandro Esquivel , Alex Lazarian

In magnetohydrodynamic (MHD) turbulence, the large-scale magnetic field sets a preferred local direction for the small-scale dynamics, altering the statistics of turbulence from the isotropic case. This happens even in the absence of a…

Plasma Physics · Physics 2017-05-10 Vladimir Zhdankin , Stanislav Boldyrev , Joanne Mason