LINEAR ACCELERATION EMISSION IN PULSAR MAGNETOSPHERES

Journal article

Linear acceleration emission occurs when a charged particle is accelerated parallel to its velocity. We evaluate the spectral and angular distribution of this radiation for several special cases, including constant acceleration (hyperbolic motion) of finite duration. Based on these results, we find the following general properties of the emission from an electron in a linear accelerator that can be characterized by an electric field E acting over a distance L: (1) the spectrum extends to a cutoff frequency , where E Schw = 1.3 × 1018 V m-1 is the Schwinger critical field and is the Compton wavelength of the electron, (2) the total energy emitted by a particle traversing the accelerator is in accordance with the standard Larmor formula where αf is the fine-structure constant, and (3) the low frequency spectrum is flat for hyperbolic trajectories, but in general depends on the details of the accelerator. We also show that linear acceleration emission complements curvature radiation in the strongly magnetized pair formation regions in pulsar magnetospheres. It dominates when the length L of the accelerator is less than the formation length ρ/γ of curvature photons, where ρ is the radius of curvature of the magnetic field lines and γ the Lorentz factor of the emitting particle. In standard static models of pair creating regions linear acceleration emission is negligible, but it is important in more realistic dynamical models in which the accelerating field fluctuates on a short length scale. © 2010. The American Astronomical Society. All rights reserved.

Authors: Reville, B; Kirk, J

• Publication status: Published
• Publisher: Institute of Physics Publishing
• Journal: ASTROPHYSICAL JOURNAL
• Volume: 715
• Issue: 1
• Pages: 186-193
• Publication date: 2010-05-20
• DOI: 10.1088/0004-637X/715/1/186
• EISSN: 1538-4357
• ISSN: 0004-637X
• Language: English
• Keywords: pulsars: general; radiation mechanisms: non-thermal; plasmas