J 2023

Magnetically threaded accretion disks in resistive magnetohydrodynamic simulations and asymptotic expansion

ČEMELJIĆ, Miljenko, Wlodzimierz KLUŹNIAK and V. PARTHASARATHY

Basic information

Original name

Magnetically threaded accretion disks in resistive magnetohydrodynamic simulations and asymptotic expansion

Authors

ČEMELJIĆ, Miljenko (191 Croatia, belonging to the institution), Wlodzimierz KLUŹNIAK (616 Poland, belonging to the institution) and V. PARTHASARATHY

Edition

ASTRONOMY & ASTROPHYSICS, LES ULIS CEDEX A, EDP SCIENCES S A, 2023, 0004-6361

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10308 Astronomy

Country of publisher

France

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

URL

RIV identification code

RIV/47813059:19630/23:A0000263

Organization unit

Institute of physics in Opava

DOI

http://dx.doi.org/10.1051/0004-6361/202140637

UT WoS

001142864300001

Keywords in English

accretion;accretion disks;magnetohydrodynamics (MHD);methods: analytical;methods: numerical;stars: neutron;X-rays: binaries

Tags

RIV24, UF

Tags

International impact, Reviewed

Links

GX21-06825X, research and development project.
Změněno: 14/2/2024 11:49, Mgr. Pavlína Jalůvková

Abstract

V originále

Aims. A realistic model of magnetic linkage between a central object and its accretion disk is a prerequisite for understanding the spin history of stars and stellar remnants. To this end, we aim to provide an analytic model in agreement with magnetohydrodynamic (MHD) simulations.Methods. For the first time, we wrote a full set of stationary asymptotic expansion equations of a thin magnetic accretion disk, including the induction and energy equations. We also performed a resistive MHD simulation of an accretion disk around a star endowed with a magnetic dipole, using the publicly available code PLUTO. We compared the analytical results with the numerical solutions, and discussed the results in the context of previous solutions of the induction equation describing the star-disk magnetospheric interaction.Results. We found that the magnetic field threading the disk is suppressed by orders of magnitude inside thin disks, so the presence of the stellar magnetic field does not strongly affect the velocity field, nor the density profile inside the disk. Density and velocity fields found in the MHD simulations match the radial and vertical profiles of the analytic solution. Qualitatively, the MHD simulations result in an internal magnetic field similar to the solutions previously obtained by solving the induction equation in the disk alone. However, the magnetic field configuration is quantitatively affected by magnetic field inflation outside the disk; this is reflected in the net torque. The torque on the star is an order of magnitude larger in the magnetic than in the non-magnetic case. Spin-up of the star occurs on a timescale comparable to the accretion timescale in the MHD case, and is an order of magnitude slower in the absence of a stellar magnetic field.
Displayed: 25/12/2024 07:29