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How stochastic, microscopic events generate deterministic, macroscopic properties is a fundamental question in physics. We address this question by developing a quantum master equation model for concentrated radical solutions, where random…

Chemical Physics · Physics 2026-05-26 Yoshiaki Uchida , Ryohei Kishi

The magnetic field of galaxies is believed to be produced by internal dynamo action, but can be affected by motion of the galaxy through the surrounding medium. Observations of polarized radio emission of galaxies located in galaxy clusters…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 D. Moss , D. Sokoloff , R. Beck

We investigate the build-up of the galactic dynamo and subsequently the origin of a magnetic driven outflow. We use a setup of an isolated disc galaxy with a realistic circum-galactic medium (CGM). We find good agreement of the galactic…

Astrophysics of Galaxies · Physics 2020-04-01 Ulrich P. Steinwandel , Klaus Dolag , Harald Lesch , Benjamin P. Moster , Andreas Burkert , Almudena Prieto

In this manuscript using the asymptotic method of multiscale nonlinear theory we construct a nonlinear theory of the appearance of large-scale structures in the stratified conductive medium with the presence of small-scale oscillations of…

Earth and Planetary Astrophysics · Physics 2016-12-30 M. I. Kopp , A. V. Tur , V. V. Yanovsky

The mean-field dynamo model is employed to study the non-linear dynamo regimes in a fully convective star of mass 0.3$M_{\odot}$ rotating with period of 10 days. For the intermediate value of the parameter of the turbulent magnetic Prandl…

Solar and Stellar Astrophysics · Physics 2017-02-01 V. V. Pipin

Galaxies are observed to host magnetic fields with a typical total strength of around 15microgauss. A coherent large-scale field constitutes up to a few microgauss of the total, while the rest is built from strong magnetic fluctuations over…

Astrophysics of Galaxies · Physics 2024-01-09 Maarit J. Korpi-Lagg , Mordecai-Mark Mac Low , Frederick A. Gent

We derive analytically the vorticity generated downstream of a two-dimensional rippled hydromagnetic shock neglecting fluid viscosity and resistivity. The growth of the turbulent component of the downstream magnetic field is driven by the…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Federico Fraschetti

By performing a global magneto-hydrodynamical simulation for the Milky Way with an axisymmetric gravitational potential, we propose that spatially dependent amplification of magnetic fields possibly explains the observed noncircular motion…

Astrophysics of Galaxies · Physics 2015-10-28 Takeru K. Suzuki , Yasuo Fukui , Kazufumi Torii , Mami Machida , Ryoji Matsumoto

For cylindrical differentially rotating plasmas, we study large-scale magnetic field generation from finite amplitude non-axisymmetric perturbations by comparing numerical simulations with quasi-linear analytic theory. When initiated with a…

High Energy Astrophysical Phenomena · Physics 2016-10-31 F. Ebrahimi , E. G. Blackman

Jetted astrophysical phenomena with black hole (BH) engines, including binary mergers, jetted tidal disruption events, and X-ray binaries, require a large-scale vertical magnetic field for efficient jet formation. However, a dynamo…

High Energy Astrophysical Phenomena · Physics 2023-11-02 Jonatan Jacquemin-Ide , François Rincon , Alexander Tchekhovskoy , Matthew Liska

We study a new type of large-scale instability, which arises in obliquely rotating stratified electroconductive fluid with an external uniform magnetic field and a small-scale external force having zero helicity. This force gives rise to…

Fluid Dynamics · Physics 2018-07-06 M. I. Kopp , K. N. Kulik , A. V. Tur , V. V. Yanovsky

In a recent paper (Phys. Rev. Lett. 94 (2005), 184506; physics/0411050) it was shown that a simple mean-field dynamo model with a spherically symmetric helical turbulence parameter alpha can exhibit a number of features which are typical…

Geophysics · Physics 2007-05-23 Frank Stefani , Gunter Gerbeth , Uwe Guenther , Mingtian Xu

The question of whether a dynamo can be triggered by gravitational collapse is of great interest, especially for the early Universe. Here, we employ supercomoving coordinates to study the magnetic field amplification from decaying…

Astrophysics of Galaxies · Physics 2025-09-11 Axel Brandenburg , Evangelia Ntormousi

The excitation and further sustenance of large-scale magnetic fields in rotating astrophysical systems, including planets, stars and galaxies, is generally thought to involve a fluid magnetic dynamo effect driven by helical…

Fluid Dynamics · Physics 2021-12-10 F. Rincon

The origin of large-scale and coherent magnetic fields in astrophysical discs is an important and long standing problem. Researchers commonly appeal to a turbulent dynamo, sustained by the magneto-rotational instability (MRI), to supply the…

High Energy Astrophysical Phenomena · Physics 2018-10-24 A. Riols , H. Latter

Cosmic-ray streaming instabilities at supernova shocks are discussed in the quasilinear diffusion formalism which takes into account the feedback effect of wave growth on the cosmic ray streaming motion. In particular, the nonresonant…

High Energy Astrophysical Phenomena · Physics 2015-05-13 Qinghuan Luo , Don Melrose

Mean-field dynamo theory has important applications in solar physics and galactic magnetism. We discuss some of the many turbulence effects relevant to the generation of large-scale magnetic fields in the solar convection zone. The…

Solar and Stellar Astrophysics · Physics 2023-11-23 Axel Brandenburg , Detlef Elstner , Youhei Masada , Valery Pipin

Using simulations of slowly rotating stratified turbulence, we show that the alpha effect responsible for the generation of astrophysical magnetic fields is proportional to the logarithmic gradient of kinetic energy density rather than that…

Solar and Stellar Astrophysics · Physics 2012-12-27 A. Brandenburg , O. Gressel , P. J. Käpylä , N. Kleeorin , M. J. Mantere , I. Rogachevskii

The extent to which large scale magnetic fields are susceptible to turbulent diffusion is important for interpreting the need for in situ large scale dynamos in astrophysics and for observationally inferring field strengths compared to…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Eric G. Blackman , Kandaswamy Subramanian

We introduce a stochastic model for a passive magnetic field in a three dimensional thin domain. The velocity field, white in time and modelling phenomenologically a turbulent fluid, acts on the magnetic field as a transport-stretching…

Probability · Mathematics 2024-02-06 Federico Butori , Franco Flandoli , Eliseo Luongo