A particle simulation for the global pulsar magnetosphere: The pulsar wind linked to the outer gaps

Tomohide Wada, Shinpei Shibata

    Research output: Contribution to journalArticlepeer-review

    13 Citations (Scopus)

    Abstract

    Soon after the discovery of radio pulsars in 1967, the pulsars are identified as strongly magnetic (typically 1012 G) rapidly rotating (∼102 - 0.1 Hz) neutron stars. However, the mechanism of particle acceleration in the pulsar magnetosphere has been a longstanding problem. The central problem is why the rotation power manifests itself in both gamma-ray beams and a highly relativistic wind of electron-positron plasmas, which excites surrounding nebulae observed in X-ray. Here we show with a three-dimensional particle simulation for the global axisymmetric magnetosphere that a steady outflow of electron-positron pairs is formed with associated pair sources, which are the gamma-ray emitting regions within the light cylinder. The magnetic field is assumed to be a dipole, and to be consistent, the pair creation rate is taken to be small, so that the model might be applicable to old pulsars such as Geminga. The pair sources are charge-deficient regions around the null surface, and we identify them as the outer gap. The wind mechanism is the electromagnetic induction which brings about fast azimuthal motion and eventually trans-field drift by radiation drag in the close vicinity of the light cylinder and beyond. The wind causes loss of particles from the system. This maintains charge deficiency in the outer gap and pair creation. The model is thus in a steady state, balancing loss and supply of particles. Our simulation implies how the wind coexists with the gamma-ray emitting regions in the pulsar magnetosphere.

    Original languageEnglish
    Pages (from-to)1460-1464
    Number of pages5
    JournalMonthly Notices of the Royal Astronomical Society
    Volume376
    Issue number4
    DOIs
    Publication statusPublished - 2007 Apr

    Keywords

    • Magnetic fields
    • Plasmas
    • Pulsars: general

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

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