Compact formulae, dynamics and radiation of charged particles under synchro-curvature losses

Daniele Viganò, Diego F. Torres, Kouichi Hirotani, Martín E. Pessah

    Research output: Contribution to journalArticleResearchpeer-review

    16 Citations (Scopus)

    Abstract

    © 2014 The Authors. We consider the fundamental problem of charged particles moving along and around a curved magnetic field line, revising the synchro-curvature radiation formulae introduced by Cheng & Zhang. We provide more compact expressions to evaluate the spectrum emitted by a single particle, identifying the key parameter that controls the transition between the curvaturedominated and the synchrotron-dominated regime. This parameter depends on the local radius of curvature of the magnetic field line, the gyration radius, and the pitch angle. We numerically solve the equations of motion for the emitting particle by considering self-consistently the radiative losses, and provide the radiated spectrum produced by a particle when an electric acceleration is balanced by its radiative losses, as it is assumed to happen in the outer gaps of pulsar's magnetospheres. We compute the average spectrum radiated throughout the particle trajectory finding that the slope of the spectrum before the peak depends on the location and size of the emission region. We show how this effect could then lead to a variety of synchrocurvature spectra. Our results reinforce the idea that the purely synchrotron or curvature losses are, in general, inadequate to describe the radiative reaction on the particle motion, and the spectrum of emitted photons. Finally, we discuss the applicability of these calculations to different astrophysical scenarios.
    Original languageEnglish
    Pages (from-to)1164-1172
    JournalMonthly Notices of the Royal Astronomical Society
    Volume447
    Issue number2
    DOIs
    Publication statusPublished - 21 Feb 2015

    Keywords

    • General-gamma-rays
    • Non-thermal-pulsars
    • Radiation mechanisms
    • Stars

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