Generation of the magnetic field in jets

Abstract

We consider dynamo action under the combined influence of turbulence and large-scale shear in sheared jets. Shear can stretch turbulent magnetic field lines in such a way that even turbulent motions showing mirror symmetry become suitable for generation of a large-scale magnetic field. We derive the integral induction equation governing the behaviour of the mean field in jets. The main result is that sheared jets may generate a large-scale magnetic field if shear is sufficiently strong. The generated mean field is mainly concentrated in a magnetic sheath surrounding the central region of a jet, and it exhibits sign reversals in the direction of the jet axis. Typically, the magnetic field in a sheath is dominated by the component along the jet that can reach equipartition with the kinetic energy of particles, The field in the central region of jets has a more disordered structure.

arXiv comment7 pages, accepted for publication in A&A

References in corpus (13)

• Structured jets in TeV BL Lac objects and radiogalaxies
• Instability of toroidal magnetic field in jets and plerions
• X-ray Emission Properties of Large Scale Jets, Hotspots and Lobes in Active Galactic Nuclei
• GENESIS: A high-resolution code for 3D relativistic hydrodynamics
• Helical Magnetic Fields Associated with the Relativistic Jets of Four BL Lac Objects
• Radiation from the Relativistic Jet: a Role of the Shear Boundary Layer
• High--Resolution 3D Simulations of Relativistic Jets
• Structure of Small-Scale Magnetic Fields in the Kinematic Dynamo Theory
• A relativistic model of the radio jets in NGC 315
• On the Magnetic Field in the Kiloparsec-Scale Jet of Radio Galaxy M 87
• Stability analysis of relativistic jets from collapsars and its implications on the short-term variability of gamma-ray bursts
• Self-Collimation and Magnetic Field Generation of Astrophysical Jets
• The magnetic field along the jets of NGC 4258 as deduced from high frequency radio observations

Cited by in corpus (7)

• The inner jet of radio galaxy NGC 315 as observed with Chandra and the VLA
• Numerical experiments on dynamo action in sheared and rotating turbulence
• Observational Effects of Anomalous Boundary Layers in Relativistic Jets
• The magnetohydrodynamic instability of current-carrying jets
• Resonance instability of axially-symmetric magnetostatic equilibria
• Offsets between X-ray and Radio Components in X-ray Jets: The AtlasX
• Analysis of the Instability Growth Rate During the Jet - Background Interaction in the Magnetic Field