The Gamma-Ray Pulsar Phenomenology in View of 3D Kinetic Global Magnetosphere Models

Abstract

Abstract We develop kinetic plasma models of pulsar magnetospheres with magnetic-field-line-dependent plasma injection that reveal the importance of various magnetosphere regions in regulating the γ-ray emission. We set different particle injection rates for the so-called open, closed, and separatrix zones. Moderate particle injection rates in open and closed zones ensure a global field structure close to the force-free structure, while the dissipation occurs mainly in and around the equatorial current sheet. The particles that are injected into the separatrix zone affect the particle populations that enter the equatorial current sheet region, and therefore the corresponding accelerating electric fields, particle energies, the spectral cutoff energy, and γ-ray efficiency. The separatrix zone models reproduce the recently discovered fundamental plane of γ-ray pulsars consistent with curvature radiation emission, the γ-ray light-curve shapes, and the radio-lag versus peak-separation correlation reported in the Fermi second pulsar catalog. The model beaming factors indicate that the pulsar total γ-ray luminosities listed in the Fermi catalogs are overestimations of the actual ones. We find that the radiation reaction limited regime starts ceasing to govern the high-energy emission for  ̇ ≲ 10 34 erg s − 1 . Our results also indicate that toward high magnetic inclination angles, the Y point around the rotational equator migrates well inside the light cylinder, sparking additional peaks in the γ-ray pulse profiles. We find that an equivalent enhanced particle injection beyond the Y point strengthens these features, making the model γ-ray light curves inconsistent with those observed.