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Related papers: Microphysical dissipation, turbulence and magnetic…

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In this study, we investigate the effect of resistivity on the dynamics of global magnetohydrodynamic accretion flows (Res-MHD) around a spinning supermassive black hole. We perform a comparative study of 2D and 3D resistive models around…

High Energy Astrophysical Phenomena · Physics 2025-07-10 Ramiz Aktar , Kuo-Chuan Pan , Toru Okuda

We study Lense-Thirring precession of inviscid and viscous misaligned $\alpha-$discs around a black hole using a gravitomagnetic term in the momentum equation. For weak misalignments, $i \lesssim 10^{\circ}$, the discs behave like rigid…

High Energy Astrophysical Phenomena · Physics 2020-08-31 Sergei Dyda , Christopher S. Reynolds

Recent high-angular resolution ALMA observations have revealed rich information about protoplanetary disks, including ubiquitous substructures and three-dimensional gas kinematics at different emission layers. One interpretation of these…

Earth and Planetary Astrophysics · Physics 2024-12-02 Xiao Hu , Zhi-Yun Li , Jaehan Bae , Zhaohuan Zhu

Prevalent around luminous accreting black holes, thin discs are challenging to resolve in numerical simulations. When the disc and black hole angular momentum vectors are misaligned, the challenge becomes extreme, requiring adaptive meshes…

High Energy Astrophysical Phenomena · Physics 2022-08-11 M. Liska , A. Tchekhovskoy , A. Ingram , M. van der Klis

Large scale magnetic field threading an accretion disk is a key ingredient in the jet formation model. The most attractive scenario for the origin of such a large scale field is the advection of the field by the gas in the accretion disk…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Xinwu Cao , H. C. Spruit

We investigate the stability of a neutrino-dominated accretion flow (NDAF), which is expected to be formed in the gravitational collapse of a massive star or the merger of a neutron star binary, based on the variable-$\alpha$ prescription.…

High Energy Astrophysical Phenomena · Physics 2019-09-04 Norita Kawanaka , Youhei Masada

The gas dynamics in protoplanetary disks (PPDs) is strongly affected by non-ideal MHD effects. Using a complex chemical reaction network with standard prescriptions for X-ray and cosmic-ray ionizations, as well as the most up-to-date…

Earth and Planetary Astrophysics · Physics 2015-05-28 Xue-Ning Bai

We show that the standard model for geometrically thin accretion disks (alpha-disks) leads to inconsistencies if selfgravity plays a role. This problem arises from the parametrization of viscosity in terms of local sound velocity and…

Astrophysics · Physics 2007-05-23 W. J. Duschl , Peter A. Strittmatter , Peter L. Biermann

We investigate the effect of shear viscosity and Ohmic resistivity on the magnetorotational instability (MRI) in vertically stratified accretion disks through a series of local simulations with the Athena code. First, we use a series of…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Jacob B. Simon , John F. Hawley , Kris Beckwith

The magnetorotational instability (MRI) is the most promising mechanism by which angular momentum is efficiently transported outwards in astrophysical discs. However, its application to protoplanetary discs remains problematic. These discs…

Earth and Planetary Astrophysics · Physics 2015-06-16 Matthew W. Kunz , Geoffroy Lesur

Axisymmetric resistive MHD simulations for radially self-similar initial conditions are performed, using the NIRVANA code. The magnetic diffusivity could occur in outflows above an accretion disk, being transferred from the underlying disk…

Solar and Stellar Astrophysics · Physics 2015-05-13 Miljenko Cemeljic , Jose Gracia , Nektarios Vlahakis , Kanaris Tsinganos

We carried out two dimensional high-resolution magnetohydrodynamic (MHD) simulations of an accretion disk around a weakly magnetized neutron star. General relativistic effects are taken into account by using pseudo-Newtonian potential of…

Astrophysics · Physics 2009-11-06 Y. Kato , H. R. Hayashi , S. Miyaji , R. Matsumoto

We examine the range of rest-mass densities, temperatures and magnetic fields involved in simulations of binary neutron-star mergers and identify the conditions under which the ideal-magnetohydrodynamics approximation breaks down and hence…

High Energy Astrophysical Phenomena · Physics 2018-11-13 Arus Harutyunyan , Antonios Nathanail , Luciano Rezzolla , Armen Sedrakian

This paper investigates the changes in spatial properties when magnetohydrodynamic (MHD) waves undergo resonant damping in the Alfv\'en continuum. The analysis is carried out for a 1D cylindrical pressure-less plasma with a straight…

Solar and Stellar Astrophysics · Physics 2020-09-18 M. Goossens , I. Arregui , R. Soler , T. Van Doorsselaere

Context. An essential facet of turbulence is the space-time intermittency of the cascade of energy that leads to coherent structures of high dissipation. Aims. In this work, we attempt to investigate systematically the physical nature of…

Astrophysics of Galaxies · Physics 2022-08-31 Thibaud Richard , Pierre Lesaffre , Edith Falgarone , Andrew Lehmann

We examine the range of rest-mass densities, temperatures and magnetic fields involved in simulations of binary neutron star mergers (BNSM) and identify the conditions under which the ideal magneto-hydrodynamics (MHD) breaks down using…

High Energy Astrophysical Phenomena · Physics 2019-07-12 Arus S. Harutyunyan

Turbulent motion driven by the magnetorotational instability (MRI) is believed to provide an anomalous viscosity strong enough to account for observed accretion rates in protostellar accretion disks. In the first of two papers, we perform…

Solar and Stellar Astrophysics · Physics 2015-06-19 Wayne O'Keeffe , Turlough P. Downes

Very strong magnetic fields can arise in non-central heavy-ion collisions at ultrarelativistic energies, which may not decay quickly in a conducting plasma. We carry out relativistic magnetohydrodynamics (RMHD) simulations to study the…

High Energy Physics - Phenomenology · Physics 2017-09-11 Arpan Das , Shreyansh S. Dave , P. S. Saumia , Ajit M. Srivastava

We study how the structure and variability of magnetohydrodynamic (MHD) turbulence in accretion discs converge with domain size. Our results are based on a series of vertically stratified local simulations, computed using the Athena code,…

Solar and Stellar Astrophysics · Physics 2015-06-04 Jacob B. Simon , Kris Beckwith , Philip J. Armitage

Understanding the complex evolution of protoplanetary disks (PPDs) and their dispersal via energetic stellar radiation are prominent challenges in astrophysics. It has recently been established that specifically the X-ray luminosity from…

Earth and Planetary Astrophysics · Physics 2023-10-04 Eleftheria Sarafidou , Oliver Gressel , Giovanni Picogna , Barbara Ercolano