Three-dimensional simulations of the magnetorotational instability in eccentric disks

Fuente: arXiv
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Main Authors: Chan, Chi-Ho, Piran, Tsvi, Krolik, Julian H.
Format: Preprint
Published: 2023
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author Chan, Chi-Ho
Piran, Tsvi
Krolik, Julian H.
author_facet Chan, Chi-Ho
Piran, Tsvi
Krolik, Julian H.
contents Previously we demonstrated that the magnetorotational instability (MRI) grows vigorously in eccentric disks, much as it does in circular disks, and we investigated the nonlinear development of the eccentric MRI without vertical gravity. Here we explore how vertical gravity influences the magnetohydrodynamic (MHD) turbulence stirred by the eccentric MRI. Similar to eccentric disks without vertical gravity, the ratio of Maxwell stress to pressure, or the Shakura--Sunyaev alpha parameter, remains ~0.01, and the local sign flip in the Maxwell stress persists. Vertical gravity also introduces two new effects. Strong vertical compression near pericenter amplifies reconnection and dissipation, weakening the magnetic field. Angular momentum transport by MHD stresses broadens the mass distribution over eccentricity at much faster rates than without vertical gravity; as a result, spatial distributions of mass and eccentricity can be substantially modified in just ~5 to 10 orbits. MHD stresses in the eccentric debris of tidal disruption events may power emission $\gtrsim$1 yr after disruption.
format Preprint
id arxiv_https___arxiv_org_abs_2312_06775
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Three-dimensional simulations of the magnetorotational instability in eccentric disks
Chan, Chi-Ho
Piran, Tsvi
Krolik, Julian H.
High Energy Astrophysical Phenomena
Plasma Physics
Previously we demonstrated that the magnetorotational instability (MRI) grows vigorously in eccentric disks, much as it does in circular disks, and we investigated the nonlinear development of the eccentric MRI without vertical gravity. Here we explore how vertical gravity influences the magnetohydrodynamic (MHD) turbulence stirred by the eccentric MRI. Similar to eccentric disks without vertical gravity, the ratio of Maxwell stress to pressure, or the Shakura--Sunyaev alpha parameter, remains ~0.01, and the local sign flip in the Maxwell stress persists. Vertical gravity also introduces two new effects. Strong vertical compression near pericenter amplifies reconnection and dissipation, weakening the magnetic field. Angular momentum transport by MHD stresses broadens the mass distribution over eccentricity at much faster rates than without vertical gravity; as a result, spatial distributions of mass and eccentricity can be substantially modified in just ~5 to 10 orbits. MHD stresses in the eccentric debris of tidal disruption events may power emission $\gtrsim$1 yr after disruption.
title Three-dimensional simulations of the magnetorotational instability in eccentric disks
topic High Energy Astrophysical Phenomena
Plasma Physics
url https://arxiv.org/abs/2312.06775