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We consider the dynamical evolution of an interstellar cloud that is initially in thermal equilibrium in the warm phase and is then subjected to a sudden increase in the pressure of its surroundings. We find that if the initial plasma beta…

Astrophysics · Physics 2009-11-13 A. J. Lim , S. A. E. G. Falle , T. W. Hartquist

We have been monitoring yearly variation in the Sun's polar magnetic fields with the Solar Optical Telescope aboard {\it Hinode} to record their evolution and expected reversal near the solar maximum. All magnetic patches in the magnetic…

Solar and Stellar Astrophysics · Physics 2015-06-05 D. Shiota , S. Tsuneta , M. Shimojo , N. Sako , D. Orozco Suárez , R. Ishikawa

We use spectro-polarimetric data recorded by Hinode to analyze the magnetic field configuration of a part of a sunspot (AR 10923) where a bundle of penumbral filaments are intruding into its umbra. We want to explore the role of the sunspot…

Solar and Stellar Astrophysics · Physics 2024-05-15 Hashem Hamedivafa

Planetesimal formation is a crucial yet poorly understood process in planet formation. It is widely believed that planetesimal formation is the outcome of dust clumping by the streaming instability (SI). However, recent analytical and…

Earth and Planetary Astrophysics · Physics 2022-01-12 Ziyan Xu , Xue-Ning Bai

We propose an in-situ formation model for inverse-polarity solar prominence and demonstrate it using self-consistent 2.5-dimensional magnetohydrodynamics simulations, including thermal conduction along magnetic fields and optically thin…

Solar and Stellar Astrophysics · Physics 2015-06-17 Takafumi Kaneko , Takaaki Yokoyama

As another step towards understanding the long-term evolution of the magnetic field in neutron stars, we provide the first simulations of ambipolar diffusion in a spherical star. Restricting ourselves to axial symmetry, we consider a…

High Energy Astrophysical Phenomena · Physics 2017-07-17 F. Castillo , A. Reisenegger , J. A. Valdivia

The transport of magnetic flux to outside of collapsing molecular clouds is a required step to allow the formation of stars. Although ambipolar diffusion is often regarded as a key mechanism for that, it has been recently argued that it may…

Solar and Stellar Astrophysics · Physics 2015-05-27 E. M. de Gouveia Dal Pino , R. Santos-Lima , A. Lazarian , M. R. M. Leão , D. Falceta-Gonçalves , G. Kowal

We show that a fast wind that expands into a bipolar nebula composed of two opposite jet-inflated bubbles can form a pair of bipolar rings around giant stars. Our model assumes three mass loss episodes: a spherical slow and dense shell, two…

Solar and Stellar Astrophysics · Physics 2016-09-07 Muhammad Akashi , Noam Soker

We show that under very general conditions, cluster plasmas threaded by weak magnetic fields are subject to very fast growing plasma instabilities driven by the anisotropy of the plasma pressure (viscous stress) with respect to the local…

Astrophysics · Physics 2008-11-26 A. A. Schekochihin , S. C. Cowley , R. M. Kulsrud , G. W. Hammett , P. Sharma

Magnetic buoyancy (MBI) and Parker instabilities are strong, generic instabilities expected to occur in most astrophysical systems with sufficiently strong magnetic fields. In galactic and accretion discs, large-scale magnetic fields are…

Astrophysics of Galaxies · Physics 2025-04-11 Yasin Qazi , Anvar. Shukurov , Frederick. A. Gent , Devika. Tharakkal , Abhijit. B. Bendre

Supersonic isothermal turbulence establishes a network of transient dense shocks that sweep up material and have a density profile described by balance between ram pressure of the background fluid versus the magnetic and gas pressure…

Astrophysics of Galaxies · Physics 2018-08-08 Philip Mocz , Blakesley Burkhart

The interstellar medium (ISM) consists of a multiphase gas, including the warm neutral medium (WNM), the unstable neutral medium (UNM), and the cold neutral medium (CNM). While significant attention has been devoted to understanding the WNM…

Astrophysics of Galaxies · Physics 2025-05-13 Yue Hu

We numerically reproduce the density profiles for filaments that are in magnetohydrostatic and pressure equilibrium with their surroundings obtained in Tomisaka (2014) and show that these equilibria are dynamically stable. If the effect of…

Astrophysics of Galaxies · Physics 2016-11-30 C. A. Burge , S. Van Loo , S. A. E. G. Falle , T. W. Hartquist

Surface magnetic fields have been detected in 5 to 10% of isolated massive stars, hosting outer radiative envelopes. They are often thought to have a fossil origin, resulting from the stellar formation phase. Yet, magnetic massive stars are…

Solar and Stellar Astrophysics · Physics 2019-09-25 Jérémie Vidal , David Cébron , Asif Ud-Doula , Evelyne Alecian

We present collapse simulations of strongly magnetised, 100 M_sun, turbulent cloud cores. Around the protostars formed during the collapse Keplerian discs with typical sizes of up to 100 AU build up in contrast to previous simulations…

Astrophysics of Galaxies · Physics 2015-06-11 D. Seifried , R. Banerjee , R. E. Pudritz , R. S. Klessen

The origin of strong magnetic fields in the Universe can be explained by amplifying weak seed fields via turbulent motions on small spatial scales and subsequently transporting the magnetic energy to larger scales. This process is known as…

We perform a long and accurate Large-Eddy Simulation of a binary neutron star merger, following the newly formed remnant up to 110 milliseconds. The combination of high-order schemes, high-resolution and the gradient subgrid-scale model…

High Energy Astrophysical Phenomena · Physics 2023-07-12 Ricard Aguilera-Miret , Carlos Palenzuela , Federico Carrasco , Daniele Viganò

The dynamics of multiple domain formation caused by the modulation instability of two-component Bose-Einstein condensates in an axially symmetric trap are studied by numerically integrating the coupled Gross-Pitaevskii equations. The…

Soft Condensed Matter · Physics 2009-11-10 Kenichi Kasamatsu , Makoto Tsubota

The plasmoid instability in evolving current sheets has been widely studied due to its effects on the disruption of current sheets, the formation of plasmoids, and the resultant fast magnetic reconnection. In this Letter, we study the role…

Plasma Physics · Physics 2018-10-24 Chuanfei Dong , Liang Wang , Yi-Min Huang , Luca Comisso , Amitava Bhattacharjee

The lower solar atmosphere consists of partially ionized turbulent plasmas harbouring velocity field, magnetic field and current density fluctuations. The correlations amongst these small scale fluctuations give rise to large scale flows…

Solar and Stellar Astrophysics · Physics 2009-04-23 V. Krishan , S. Masuda