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Following the early paper of Goldreich & Julian (1969), polar-cap models have usually assumed that the closed sector of a pulsar magnetosphere corotates with the neutron star. Recent work by Melrose & Yuen has been a reminder that in an…

High Energy Astrophysical Phenomena · Physics 2015-09-09 P. B. Jones

We study plasma flows above pulsar polar caps using time-dependent simulations of plasma particles in the self-consistent electric field. The flow behavior is controlled by the dimensionless parameter alpha=(j/c rho_GJ) where j is the…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Alexander Y. Chen , Andrei M. Beloborodov

Little attention has so far been paid to the division of the observed population between pulsars of the two spin directions that are possible. Almost all pulsars with positive corotational charge density at the polar caps are expected to…

High Energy Astrophysical Phenomena · Physics 2015-06-04 P. B. Jones

The heating of the real polar cap surface of radio pulsars by the bombardment of ultra-relativistic charges is studied. The real polar cap is a significantly smaller area within or close by the conventional polar cap which is encircled by…

High Energy Astrophysical Phenomena · Physics 2020-07-20 Maciej Sznajder , Ulrich Geppert

The ability of the neutron star surface to supply all or only part of the charges filling the pulsar magnetosphere is crucial for the physics prevailing within it, with direct consequences for the possible formation of pair creation…

Astrophysics · Physics 2009-10-31 A. Jessner , H. Lesch , T. Kunzl

Pair cascades in polar cap regions of neutron stars are considered to be an essential process in various models of coherent radio emissions of pulsars. The cascades produce pair plasma bunch discharges in quasi-periodic spark events. The…

High Energy Astrophysical Phenomena · Physics 2024-11-06 Jan Benáček , Andrey Timokhin , Patricio A. Muñoz , Axel Jessner , Tatiana Rievajová , Martin Pohl , Jörg Büchner

In the canonical model of a pulsar, rotational energy is transmitted through the surrounding plasma via two electrical circuits, each connecting to the star over a small region known as a "polar cap." For a dipole-magnetized star, the polar…

High Energy Astrophysical Phenomena · Physics 2018-01-03 Samuel E. Gralla , Alexandru Lupsasca , Alexander Philippov

An analytical model for oscillating pair creation above the pulsar polar cap is presented in which the parallel electric field is treated as a large amplitude, superluminal, electrostatic wave. An exact formalism for such wave is derived in…

Astrophysics · Physics 2009-11-13 Q. Luo , D. B. Melrose

The characteristics of the high-energy emission from polar cap accelerators will be discussed. Particles accelerated in the "slot gap" near the polar cap rim will reach altitudes of several stellar radii before initiating pair cascades,…

Astrophysics · Physics 2007-05-23 Alice K. Harding , Alexander G. Muslimov

It has been argued in previous papers that an ion-proton plasma is formed at the polar caps of neutron stars with positive polar-cap corotational charge density. The present paper does not offer a theory of the development of turbulence…

High Energy Astrophysical Phenomena · Physics 2015-12-09 P B Jones

Modifications to polar-gap models for pulsars are discussed for the case where the surface magnetic field, $B_\S$, of the neutron star is strong. For $B\ga4\times10^8\rm\,T$, the curvature $\gamma$-quanta emitted tangentially to the curved…

Astrophysics · Physics 2015-06-24 V. V. Usov , D. B. Melrose

We revisit particle acceleration in the polar cap region of a neutron star by taking into account both general relativistic effects and the presence of toroidal oscillations at the star surface. In particular, we address the question of…

High Energy Astrophysical Phenomena · Physics 2015-03-11 Olindo Zanotti , Viktoriya Morozova , Bobomurat Ahmedov

The study of pulsars in the three and a half decades since their discovery has highlighted a handful of issues critical to their understanding. To date there is no consensus on the physical mechanism for their radio radio emission, despite…

Astrophysics · Physics 2009-11-10 Matthew G. Baring

This paper continues a previous study of neutron stars with positive polar-cap corotational charge density in which free emission of ions maintains the surface electric-field boundary condition E.B = 0. The composition of the accelerated…

High Energy Astrophysical Phenomena · Physics 2015-05-27 P. B. Jones

Pulsar "standard model", that considers a pulsar as a rotating magnetized conducting sphere surrounded by plasma, is generalized to the case of oscillating star. We developed an algorithm for calculation of the Goldreich-Julian charge…

Astrophysics · Physics 2008-11-26 Andrey N. Timokhin

Rough estimates and upper limits on current and particle densities form the basis of most of the canonical pulsar models. Whereas the surface of the rotating neutron star is capable of supplying sufficient charges to provide a current that,…

Astrophysics · Physics 2007-05-23 A. Jessner , H. Lesch , T. Kunzl

We explore the pulsar slot gap 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 stream lines…

Astrophysics · Physics 2009-11-10 Alex G. Muslimov , Alice K. Harding

Pulsed emission from gamma-ray pulsars originates inside the magnetosphere, from radiation by charged particles accelerated near the magnetic poles or in the outer gaps. In polar cap models, the high energy spectrum is cut off by magnetic…

Astrophysics · Physics 2009-10-31 Alice K. Harding

Protons produced in electromagnetic showers formed by the reverse-electron flux are usually the largest component of the time-averaged polar-cap open magnetic flux-line current in neutron stars with positive corotational charge density.…

High Energy Astrophysical Phenomena · Physics 2015-05-14 P B Jones

A number of disparate observational and theoretical pieces of evidence indicate that, contrary to the conventional wisdom, neutron stars' closed field lines are populated by dense, hot plasma and may be responsible for producing some radio…

Astrophysics · Physics 2008-11-26 Maxim Lyutikov
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