Magnetospheric Accretion and Ejection of Matter in Resistive Magnetohydrodynamic Simulations

Fuente: arXiv
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Auteurs principaux: Čemeljić, Miljenko, Shang, Hsien, Chiang, Tzu-Yang
Format: Preprint
Publié: 2011
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author Čemeljić, Miljenko
Shang, Hsien
Chiang, Tzu-Yang
author_facet Čemeljić, Miljenko
Shang, Hsien
Chiang, Tzu-Yang
contents The ejection of matter in the close vicinity of a young stellar object is investigated, treating the accretion disk as a gravitationally bound reservoir of matter. By solving the resistive MHD equations in 2D axisymmetry using our version of the Zeus-3D code with newly implemented resistivity, we study the effect of magnetic diffusivity in the magnetospheric accretion-ejection mechanism. Physical resistivity was included in the whole computational domain so that reconnection is enabled by the physical as well as the numerical resistivity. We show, for the first time, that quasi-stationary fast ejecta of matter, which we call {\em micro-ejections}, of small mass and angular momentum fluxes, can be launched from a purely resistive magnetosphere. They are produced by a combination of pressure gradient and magnetic forces, in presence of ongoing magnetic reconnection along the boundary layer between the star and the disk, where a current sheet is formed. Mass flux of micro-ejection increases with increasing magnetic field strength and stellar rotation rate, and is not dependent on the disk to corona density ratio and amount of resistivity.
format Preprint
id arxiv_https___arxiv_org_abs_1112_6226
institution arXiv
publishDate 2011
record_format arxiv
spellingShingle Magnetospheric Accretion and Ejection of Matter in Resistive Magnetohydrodynamic Simulations
Čemeljić, Miljenko
Shang, Hsien
Chiang, Tzu-Yang
Solar and Stellar Astrophysics
High Energy Astrophysical Phenomena
The ejection of matter in the close vicinity of a young stellar object is investigated, treating the accretion disk as a gravitationally bound reservoir of matter. By solving the resistive MHD equations in 2D axisymmetry using our version of the Zeus-3D code with newly implemented resistivity, we study the effect of magnetic diffusivity in the magnetospheric accretion-ejection mechanism. Physical resistivity was included in the whole computational domain so that reconnection is enabled by the physical as well as the numerical resistivity. We show, for the first time, that quasi-stationary fast ejecta of matter, which we call {\em micro-ejections}, of small mass and angular momentum fluxes, can be launched from a purely resistive magnetosphere. They are produced by a combination of pressure gradient and magnetic forces, in presence of ongoing magnetic reconnection along the boundary layer between the star and the disk, where a current sheet is formed. Mass flux of micro-ejection increases with increasing magnetic field strength and stellar rotation rate, and is not dependent on the disk to corona density ratio and amount of resistivity.
title Magnetospheric Accretion and Ejection of Matter in Resistive Magnetohydrodynamic Simulations
topic Solar and Stellar Astrophysics
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/1112.6226