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Title: Relativistic MHD simulations of poynting flux-driven jets

Abstract

Relativistic, magnetized jets are observed to propagate to very large distances in many active galactic nuclei (AGNs). We use three-dimensional relativistic MHD simulations to study the propagation of Poynting flux-driven jets in AGNs. These jets are already assumed to be being launched from the vicinity (∼10{sup 3} gravitational radii) of supermassive black holes. Jet injections are characterized by a model described in Li et al., and we follow the propagation of these jets to ∼parsec scales. We find that these current-carrying jets are always collimated and mildly relativistic. When α, the ratio of toroidal-to-poloidal magnetic flux injection, is large the jet is subject to nonaxisymmetric current-driven instabilities (CDI) which lead to substantial dissipation and reduced jet speed. However, even with the presence of instabilities, the jet is not disrupted and will continue to propagate to large distances. We suggest that the relatively weak impact by the instability is due to the nature of the instability being convective and the fact that the jet magnetic fields are rapidly evolving on Alfvénic time scales. We present the detailed jet properties and show that far from the jet launching region, a substantial amount of magnetic energy has been transformed into kinetic energy andmore » thermal energy, producing a jet magnetization number σ < 1. In addition, we have also studied the effects of a gas pressure supported 'disk' surrounding the injection region, and qualitatively similar global jet behaviors were observed. We stress that jet collimation, CDIs, and the subsequent energy transitions are intrinsic features of current-carrying jets.« less

Authors:
; ;  [1]
  1. Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
Publication Date:
OSTI Identifier:
22348149
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 781; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALFVEN WAVES; BLACK HOLES; DISTANCE; GALAXIES; GALAXY NUCLEI; INJECTION; INSTABILITY; MAGNETIC FIELDS; MAGNETIC FLUX; MAGNETIZATION; MAGNETOHYDRODYNAMICS; RELATIVISTIC RANGE; SIMULATION; STRESSES

Citation Formats

Guan, Xiaoyue, Li, Hui, and Li, Shengtai. Relativistic MHD simulations of poynting flux-driven jets. United States: N. p., 2014. Web. doi:10.1088/0004-637X/781/1/48.
Guan, Xiaoyue, Li, Hui, & Li, Shengtai. Relativistic MHD simulations of poynting flux-driven jets. United States. https://doi.org/10.1088/0004-637X/781/1/48
Guan, Xiaoyue, Li, Hui, and Li, Shengtai. 2014. "Relativistic MHD simulations of poynting flux-driven jets". United States. https://doi.org/10.1088/0004-637X/781/1/48.
@article{osti_22348149,
title = {Relativistic MHD simulations of poynting flux-driven jets},
author = {Guan, Xiaoyue and Li, Hui and Li, Shengtai},
abstractNote = {Relativistic, magnetized jets are observed to propagate to very large distances in many active galactic nuclei (AGNs). We use three-dimensional relativistic MHD simulations to study the propagation of Poynting flux-driven jets in AGNs. These jets are already assumed to be being launched from the vicinity (∼10{sup 3} gravitational radii) of supermassive black holes. Jet injections are characterized by a model described in Li et al., and we follow the propagation of these jets to ∼parsec scales. We find that these current-carrying jets are always collimated and mildly relativistic. When α, the ratio of toroidal-to-poloidal magnetic flux injection, is large the jet is subject to nonaxisymmetric current-driven instabilities (CDI) which lead to substantial dissipation and reduced jet speed. However, even with the presence of instabilities, the jet is not disrupted and will continue to propagate to large distances. We suggest that the relatively weak impact by the instability is due to the nature of the instability being convective and the fact that the jet magnetic fields are rapidly evolving on Alfvénic time scales. We present the detailed jet properties and show that far from the jet launching region, a substantial amount of magnetic energy has been transformed into kinetic energy and thermal energy, producing a jet magnetization number σ < 1. In addition, we have also studied the effects of a gas pressure supported 'disk' surrounding the injection region, and qualitatively similar global jet behaviors were observed. We stress that jet collimation, CDIs, and the subsequent energy transitions are intrinsic features of current-carrying jets.},
doi = {10.1088/0004-637X/781/1/48},
url = {https://www.osti.gov/biblio/22348149}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 781,
place = {United States},
year = {Mon Jan 20 00:00:00 EST 2014},
month = {Mon Jan 20 00:00:00 EST 2014}
}