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The interstellar medium of the Milky Way and nearby disk galaxies harbours large-scale coherent magnetic fields of Microgauss strength, that can be explained via the action of a mean-field dynamo. As in our previous work, we aim to quantify…

Astrophysics of Galaxies · Physics 2020-03-18 Oliver Gressel , Detlef Elstner

Intermittency in fluid turbulence can be evidentiated through the analysis of Probability Distribution Functions (PDF) of velocity fluctuations, which display a strong non-gaussian behavior at small scales. In this paper we investigate the…

Chaotic Dynamics · Physics 2007-05-23 V. Carbone , P. Giuliani , L. Sorriso-Valvo , P. Veltri , R. Bruno , E. Martines , V. Antoni

I discuss recent advances in the understanding of non-equilibrium gauge field dynamics in plasmas which have particle distributions which are locally anisotropic in momentum space. In contrast to locally isotropic plasmas such anisotropic…

High Energy Physics - Phenomenology · Physics 2008-10-18 Michael Strickland

By means of three dimensional high-resolution hybrid simulations we study the properties of the magnetic field spectral anisotropies near and beyond ion kinetic scales. By using both a Fourier analysis and a local analysis based on…

Solar and Stellar Astrophysics · Physics 2019-04-18 Simone Landi , Luca Franci , Emanuele Papini , Andrea Verdini , Lorenzo Matteini , Petr Hellinger

An electron or electron-positron beam streaming through a plasma is notoriously prone to micro-instabilities. For a dilute ultrarelativistic infinite beam, the dominant instability is a mixed mode between longitudinal two-stream and…

We use three-dimensional hydrodynamic numerical simulations to study phase transformations occurring in a clumpy interstellar gas exposed to time-dependent volumetric heating. To mimic conditions in the Galactic interstellar medium, we take…

Astrophysics · Physics 2009-11-07 Alexei G. Kritsuk , Michael L. Norman

The filamentary structure of the molecular interstellar medium and the potential link of this morphology to star formation have been brought into focus recently by high resolution observational surveys. An especially puzzling matter is that…

Astrophysics of Galaxies · Physics 2016-04-20 Evangelia Ntormousi , Patrick Hennebelle , Philippe André , Jacques Masson

We use three dimensional radiation magneto-hydrodynamic simulations to study the effects of magnetic fields on the energy transport and structure of radiation pressure dominated main sequence massive star envelopes at the region of the iron…

Solar and Stellar Astrophysics · Physics 2017-07-19 Yan-Fei Jiang , Matteo Cantiello , Lars Bildsten , Eliot Quataert , Omer Blaes

Fluctuation dynamos provide a robust mechanism for amplifying weak seed magnetic fields in turbulent astrophysical plasmas. However, their behaviour in the highly compressible regimes characteristic of the interstellar medium remains…

Astrophysics of Galaxies · Physics 2026-02-18 Ameya Uday Nagdeo , Sharanya Sur , Bhargav Vaidya

The parametric decay of finite-size Alfv\'en waves in nonperiodic low-beta plasmas is investigated using one-dimensional hybrid simulations. Compared with the usual small periodic system, a wave packet in a large system under the absorption…

Plasma Physics · Physics 2021-10-28 Feiyu Li , Xiangrong Fu , Seth Dorfman

The interstellar magnetic field strength and gas density are observed to be correlated, but there is a large dispersion in this relation. In particular, the magnetic field is often observed to be weaker than expected. It is usually assumed…

Astrophysics · Physics 2009-11-06 Ellen G. Zweibel

We present a spatially dependent framework for the existence and propagation of nonlinear kinetic Alfv\'en (KA) structures in the interstellar medium (ISM). Using a multi-component analytical model that incorporates the diffuse warm ionized…

Plasma Physics · Physics 2026-02-12 Manpreet Singh , Siming Liu , N. S. Saini

Observations of galaxy clusters show that the intracluster medium (ICM) is likely to be turbulent and is certainly magnetized. The properties of this magnetized turbulence are determined both by fundamental nonlinear magnetohydrodynamic…

Astrophysics · Physics 2008-11-26 A. A. Schekochihin , S. C. Cowley

Several lines of evidence suggest that protogalactic and galactic environments manage to grow magnetic field very rapidly. This makes the theoretical problem of achieving rapid growth of magnetic fields in such environments difficult.…

Astrophysics · Physics 2009-11-10 D. S. Balsara , J. S. Kim , M. M. Mac Low , G. Mathews

Using two-dimensional hybrid-kinetic simulations, we explore the nonlinear "interruption" of standing and traveling shear-Alfv\'en waves in collisionless plasmas. Interruption involves a self-generated pressure anisotropy removing the…

Plasma Physics · Physics 2017-12-14 J. Squire , M. W. Kunz , E. Quataert , A. A. Schekochihin

The convective envelopes of cool main-sequence stars harbour magnetic fields with a complex global and local structure. These fields affect the near-surface convection and the outer stellar atmospheres in many ways and are responsible for…

Solar and Stellar Astrophysics · Physics 2015-09-02 Benjamin Beeck , Manfred Schüssler , Robert H. Cameron , Ansgar Reiners

Compressible turbulence, especially the magnetized version of it, traditionally has a bad reputation with researchers. However, recent progress in theoretical understanding of incompressible MHD as well as that in computational capabilities…

Astrophysics · Physics 2007-05-23 Jungyeon Cho , A. Lazarian

In this paper, the nonlinear evolution of a bistable interstellar medium is investigated using two-dimensional simulations with a realistic cooling rate, thermal conduction, and physical viscosity. The calculations are performed using…

Astrophysics of Galaxies · Physics 2015-06-17 Kazunari Iwasaki , Shu-ichiro Inutsuka

In 2012, Voyager 1 became the first in situ probe of the very local interstellar medium. The Voyager 1 Plasma Wave System has given point estimates of the plasma density spanning about 30 astronomical units (au) of interstellar space,…

Astrophysics of Galaxies · Physics 2021-12-14 S. K. Ocker , J. M. Cordes , S. Chatterjee , D. A. Gurnett , W. S. Kurth , S. R. Spangler

Primordial fluctuations in the cosmic density are usually assumed to take the form of a Gaussian random field that evolves under the action of gravitational instability. In the early stages, while they have low amplitude, the fluctuations…

Astrophysics · Physics 2009-11-07 Peter Watts , Peter Coles