Accretion disc backflow in resistive MHD simulations

@article{76803,
   author = {Mishra, R. and Čemeljić, Miljenko and Kluźniak, Wlodzimierz},
   article_number = {3},
   doi = {http://dx.doi.org/10.1093/mnras/stad1691},
   keywords = {accretion; accretion discs;magnetic fields;(magnetohydrodynamics) MHD;methods: numerical},
   language = {eng},
   issn = {0035-8711},
   journal = {Monthly Notices of the Royal Astronomical Society},
   title = {Accretion disc backflow in resistive MHD simulations},
   url = {https://academic.oup.com/mnras/article/523/3/4708/7192460?login=true},
   volume = {523},
   year = {2023}
}

TY  - JOUR
ID  - 76803
AU  - Mishra, R. - Čemeljić, Miljenko - Kluźniak, Wlodzimierz
PY  - 2023
TI  - Accretion disc backflow in resistive MHD simulations
JF  - Monthly Notices of the Royal Astronomical Society
VL  - 523
IS  - 3
SP  - 4708-4719
EP  - 4708-4719
SN  - 00358711
KW  - accretion
KW  - accretion discs;magnetic fields;(magnetohydrodynamics) MHD;methods: numerical
UR  - https://academic.oup.com/mnras/article/523/3/4708/7192460?login=true
N2  - We investigate accretion onto a central star, with the size, rotation rate, and magnetic dipole of a young stellar object, to study the flow pattern (velocity and density) of the fluid within and outside of the disc. We perform resistive magnetohydrodynamic (MHD) simulations of thin discs, varying the parameters such as the stellar rotation rate and (anomalous) coefficients of viscosity and resistivity in the disc. To provide a benchmark for the results and to compare them with known analytic results, we also perform purely hydrodynamic (HD) simulations for the same problem. Although obtained for different situations with differing inner boundary condition, the disc structure in the HD simulations closely follows the analytic solution of Kluzniak and Kita - in particular, a region of 'mid-plane' backflow exists in the right range of radii, depending on the viscosity parameter. In the MHD solutions, whenever the magnetic Prandtl number does not exceed a certain critical value, the mid-plane backflow exists throughout the accretion disc, extending all the way down to the foot point of the accretion funnel flow where the disc transitions to a magnetic funnel flow. For values of the magnetic Prandtl number close to the critical value the backflow and the inner disc undergo a quasi-periodic radial oscillation, otherwise the backflow is steady, as is the disc solution. From our results, supplemented by our reading of the literature, we suggest that mid-plane backflow is a real, physical, and not only numerical feature of at least some accretion discs.
ER  - 

MISHRA, R., Miljenko ČEMELJI$\backslash$'C a Wlodzimierz KLU$\backslash$'ZNIAK. Accretion disc backflow in resistive MHD simulations. \textit{Monthly Notices of the Royal Astronomical Society}. 2023, roč.~523, č.~3, s.~4708-4719. ISSN~0035-8711. Dostupné z: https://dx.doi.org/10.1093/mnras/stad1691.