Pulsar Polar Cap Heating and Surface Thermal X-Ray Emission. I. Curvature Radiation Pair Fronts

By A. Harding, A. Muslimov. 2001

157 citations recorded by the source corpus.

We investigate the effect of pulsar polar cap (PC) heating produced by positrons returning from the upper pair formation front. Our calculations are based on a self-consistent treatment of the pair dynamics and the effect of electric field screening by the returning positrons. We calculate the resultant X-ray luminosities and discuss the dependence of the PC heating efficiencies on pulsar parameters, such as characteristic spin-down age, spin period, and surface magnetic field strength. In this study we concentrate on the regime where the pairs are produced in a magnetic field by curvature photons emitted by accelerating electrons. Our theoretical results are not in conflict with the available observational X-ray data and suggest that the effect of PC heating should significantly contribute to the thermal X-ray fluxes from middle-aged and old pulsars. The implications for current and future X-ray observations of pulsars are briefly outlined.

Subfields: Astronomy and Astrophysics, Geophysics

View Paper: https://www.semanticscholar.org/paper/37f4a5db85dc49e96611508d372001c1d69263cc

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Geophysics

Citations in the corpus

Pulsar Polar Cap Heating and Surface Thermal X-Ray Emission. II. Inverse Compton Radiation Pair Fronts (2001, methodology): “In the first paper (Harding & Muslimov 2001; Paper I), we have presented our results for screening and PC heating by CR PFFs, as in Arons (1981), but using the frame-dragging electric field of Muslimov & Tsygan (1992).”
Physics of strongly magnetized neutron stars (2006, background): “In space–charge limited flow models (e.g. Arons and Scharlemann (1979), Harding and Muslimov (2001)), the trapped positrons needed to screen the E‖ are only a small fraction of the number of primary electrons.”
High-Altitude Particle Acceleration and Radiation in Pulsar Slot Gaps (2004, result): “We have found from our previous studies (Harding & Muslimov 2001 [HM01], 2002 [HM02]) that the youngest and most energetic pulsars can produce pairs from curvature radiation (CR) of primary electrons, which are numerous enough to screen the electric field.”
TOWARD A REALISTIC PULSAR MAGNETOSPHERE (2011, background): “This charge density excess is small relative to the total charge, i.e. ∆ρ/ρ = ǫ ≪ 1 and the current that flows into the magnetosphere above the PFF has J/ρc ≃ 1 (Harding & Muslimov 2001).”
An Updated Mass–Radius Analysis of the 2017–2018 NICER Data Set of PSR J0030+0451 (2023, methodology): “…band, we use parameterized models that are motivated by theoretical studies of return currents and polar cap heating in rotation-powered pulsars ( Harding & Muslimov 2001, 2011; Timokhin & Arons 2013; Kalapotharakos et al. 2014; Gralla et al. 2017; Lockhart et al. 2019; Kalapotharakos et al.…”
Extended Acceleration in Slot Gaps and Pulsar High-Energy Emission (2003, background): “In the last few years, a self-consistent model of PC acceleration has been developed, which includes effects of general relativity (Harding & Muslimov 1998, hereafter HM98) and screening by pairs (Harding & Muslimov 2001, hereafter HM01; Harding & Muslimov 2002, hereafter HM02).”
The Radius of the High-mass Pulsar PSR J0740+6620 with 3.6 yr of NICER Data (2024, background): “Their thermal emission is dominated by surface regions heated by the bombardment of charged particles from a magne-tospheric return current (see, e.g., Ruderman & Suther-land 1975; Arons 1981; Harding & Muslimov 2001).”
High-Altitude Emission from Pulsar Slot Gaps: The Crab Pulsar (2008, background): “Radiation from these charges forms electron-positron pairs in the strong magnetic field, which can screen the Ek above a pair formation front (PFF) in a distance small compared to the acceleration distance, which is typically less than a stellar radius (AS79; Harding & Muslimov 2001).”