High-Altitude Particle Acceleration and Radiation in Pulsar Slot Gaps

By A. Muslimov, A. Harding. 2004

210 citations recorded by the source corpus.

We explore the pulsar slot gap (SG) electrodynamics up to very high altitudes, where for most relatively rapidly rotating pulsars both the standard small-angle approximation and the assumption that the magnetic field lines are ideal streamlines break down. We address the importance of the electrodynamic conditions at the SG boundaries and the occurrence of a steady state drift of charged particles across the SG field lines at very high altitudes. These boundary conditions and the deviation of particle trajectories from streamlines determine the asymptotic behavior of the scalar potential at all radii from the polar cap (PC) to near the light cylinder. As a result, we demonstrate that the steady state accelerating electric field, E∥, must approach a small and constant value at high altitude above the PC. This E∥ is capable of maintaining electrons moving with high Lorentz factors (~few × 107) and emitting curvature γ-ray photons up to nearly the light cylinder. By numerical simulations, we show that primary electrons accelerating from the PC surface to high altitude in the SG along the outer edge of the open field region will form caustic emission patterns on the trailing dipole field lines. Acceleration and emission in such an extended SG may form the physical basis of a model that can successfully reproduce some pulsar high-energy light curves.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/857848f6b83a0e47450fe511a0eaca425391e719

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Citations in the corpus

THE FIRST FERMI LARGE AREA TELESCOPE CATALOG OF GAMMA-RAY PULSARS (2009, background): “In both SG (Muslimov & Harding 2004) and OG (Zhang et al. 2004; Hirotani 2008) models, E‖ ∝ BLC w 2, where w is the gap width.”
Modelling high-energy pulsar light curves from first principles (2015, background): “…and open field lines, extending from the stellar surface up to the light-cylinder in some cases (slot-gap Arons & Scharlemann 1979; Arons 1983; Muslimov & Harding 2003, 2004, two-pole caustics Dyks & Rudak 2003 models), but the Fermi-LAT data currently favor emission from the outer…”
High-Altitude Emission from Pulsar Slot Gaps: The Crab Pulsar (2008, background): “The radiation model of Muslimov & Harding (2004) was not complete, since it did not include all sources of primary particle radiation and all particles capable of contributing to high-altitude radiation.”
FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE CRAB PULSAR AND NEBULA (2009, background): “…charge surface and the light cylinder, and the two-pole caustic (TPC) models (Dyks & Rudak 2003) which might be realized in SG acceleration models (Muslimov & Harding 2004), in which the emission takes place between the neutron star surface and the light cylinder along the last open field lines.”
AN ATLAS FOR INTERPRETING γ-RAY PULSAR LIGHT CURVES (2008, background): “Conversely, it has been argued that acceleration at the rims of the polar caps may extend to very high altitude (Muslimov & Harding 2004), effectively pushing the polar cap activity outward.”
MODELING OF GAMMA-RAY PULSAR LIGHT CURVES USING THE FORCE-FREE MAGNETIC FIELD (2009, background): “…al. 1978; Daugherty & Harding 1982, 1996), the slot gap model (SG, or two-pole caustic model, TPC for short; Arons & Scharlemann 1979; Arons 1983; Muslimov & Harding 2003, 2004; Dyks & Rudak 2003; Dyks et al. 2004), the outer gap model(OG, Cheng et al. 1986a,b; Romani & Yadigaroglu 1995;…”
TOWARD A REALISTIC PULSAR MAGNETOSPHERE (2011, background): “Slot gap models (Muslimov & Harding 2004; Harding et al. 2008), with acceleration and emission in a narrow layer along the last open field line from the neutron star surface to near the LC, and outer gap models (Romani & Yadigaroglu 1995; Romani 1996; Takata et al. 2007) produce light curves and…”