2001/01/31 by Kouichi Hirotani, K. Hirotani, S. Shibata +1 · 4 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics #Astrophysics and Cosmic Phenomena #Charge density #Curvature #Earthquake Detection and Analysis #Electric field #Electron #Field line #Gamma ray #Geometry #Magnetic field #Magnetosphere #Nuclear physics #Optics #Photon #Physics #Pulsar #Pulsars and Gravitational Waves Research #Quantum mechanics #astro-ph
paper · pdf · doi:10.1086/322468
17 pages, 12 figures, submitted to ApJ
arxiv created 2001/04/05 · openalex publication_date 2001/09/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate a stationary pair-production cascade in the outer magnetosphere of a spinning neutron star. The charge depletion due to global flows of charged particles causes a large electric field along the magnetic field lines. Migratory electrons and/or positrons are accelerated by this field to radiate curvature gamma rays, some of which collide with the X-rays to materialize as pairs in the gap. The replenished charges partially screen the electric field, which is self-consistently solved together with the distribution functions of particles and gamma rays. If no current is injected at either of the boundaries of the accelerator, the gap is located around the conventional null surface, where the local Goldreich-Julian charge density vanishes. However, we first find that the gap position shifts outward (or inward) when particles are injected at the inner (or outer) boundary. Applying the theory to the Crab pulsar, we demonstrate that the pulsed TeV flux does not exceed the observational upper limit for moderate infrared photon density and that the gap should be located near to or outside of the conventional null surface so that the observed spectrum of pulsed GeV fluxes may be emitted via a curvature process. Some implications of the existence of a solution for a super Goldreich-Julian current are discussed.