Particle Acceleration in Shearing Flows: Efficiencies and Limits

Abstract

We examine limits to the efficiency for particles acceleration in shearing flows, showing that relativistic flow speeds are required for efficient gradual shear acceleration. We estimate maximum achievable particle energies for parameters applicable to relativistic AGN jets. The implications of our estimates is that if large-scale jets are relativistic, then efficient electron acceleration up to several PeV, and proton acceleration up to several EeV energies appears feasible. This suggests that shear particle acceleration could lead to a continued energization of synchrotron X-ray emitting electrons, and be of relevance for the production of ultra-high-energy cosmic-ray particles.

ApJL accepted, 5 pages, 2 figures

References in corpus (10)

• A numerical simulation of the evolution and fate of a FRI jet. The case of 3C 31
• Formation of dynamical structures in relativistic jets: the FRI case
• The jet of Markarian 501 from millions of Schwarzschild radii down to a few hundreds
• A microscopic analysis of shear acceleration
• Are Spine--Sheath Polarization Structures in the Jets of Active Galactic Nuclei Associated with Helical Magnetic Fields?
• Particle Acceleration in Mildly Relativistic Shearing Flows: the Interplay of Systematic and Stochastic Effects, and the Origin of the Extended High-energy Emission in AGN Jets
• First-Epoch VLBA Imaging of Twenty New TeV Blazars
• Detection of Superluminal Motion in the X-Ray Jet of M87
• Shear Acceleration in Expanding Flows
• On radiative acceleration in spine-sheath structured blazar jets