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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

Analysis of plasma acceleration in pulsars with positive corotational charge density has shown that any element of area on the polar cap is bi-stable: it can be in phases either of pure proton emission or of mixed ions and protons (the ion…

High Energy Astrophysical Phenomena · Physics 2015-06-18 P. B. Jones

A model for pulsars with polar-cap magnetic flux density B antiparallel with rotational spin is described. It recognizes the significance of two elementary processes, proton production in electromagnetic showers and photoelectric…

High Energy Astrophysical Phenomena · Physics 2015-06-15 P B Jones

It is shown that the time-variability inherent in the ion-proton polar cap leads naturally to growth of Langmuir modes on narrow bundles of magnetic flux lines and that the observed size of micropulses is consistent with the smallest such…

High Energy Astrophysical Phenomena · Physics 2017-05-10 P B Jones

Ions, protons and possibly a small flux of electrons and positrons are accelerated outward from the polar cap of a normal or millisecond pulsar whose rotational spin is antiparallel with its magnetic moment. The Langmuir modes of this…

High Energy Astrophysical Phenomena · Physics 2015-06-22 P. B. Jones

The classical vacuum gap model of Ruderman & Sutherland, in which spark-associated subbeams of subpulse emission circulate around the magnetic axis due to the EB drift, provides a natural and plausible physical mechanism of the subpulse…

Astrophysics · Physics 2009-11-07 Janusz Gil , George I. Melikidze , Ulrich Geppert

Electric currents j flow along the open magnetic field lines from the polar caps of neutron stars. Activity of a polar cap depends on the ratio \alpha=j/c\rho_GJ, where \rho_GJ is the corotation charge density. The customary assumption…

Astrophysics · Physics 2009-11-13 Andrei M. Beloborodov

Pulsars often display systematic variations in the position and/or intensity of the subpulses, the components that comprise each single pulse. Although the drift of these subpulses was observed in the early years of pulsar research, and…

High Energy Astrophysical Phenomena · Physics 2024-07-30 Andrzej Szary , Joeri van Leeuwen

Several classes of neutron star are sources of coherent emission at frequencies of 10^2 - 10^3 MHz: others are radio-quiet. The primary emission spectra are broadly universal in form over many orders of magnitude in rotation period and…

High Energy Astrophysical Phenomena · Physics 2015-06-24 P. B. Jones

We derive the exact drift velocity of plasma in the pulsar polar cap, in contrast to the order-of-magnitude expressions presented by Ruderman & Sutherland (1975) and generally used throughout the literature. We emphasize that the drift…

High Energy Astrophysical Phenomena · Physics 2015-06-03 J. van Leeuwen , A. N. Timokhin

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

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

About 200 radio pulsars have been observed to exhibit nulling episodes - short and long. We find that the nulling fraction of a pulsar does not have any obvious correlation with any of the intrinsic pulsar parameters. It also appears that…

High Energy Astrophysical Phenomena · Physics 2019-10-23 Sushan Konar , Uddeepta Deka

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

Expanding on the comment by Lyne et al (2017), that intermittent pulsars tend to congregate near a stripe in the logarithmic period versus period-derivative diagram, representing a small range of polar cap electric potential, as well as the…

High Energy Astrophysical Phenomena · Physics 2021-11-24 Fan Zhang

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

In this study we propose a classification scheme for the phenomenon of subpulse drifting in pulsars. We have assembled an exhaustive list of pulsars which exhibit subpulse drifting from previously published results as well as recent…

High Energy Astrophysical Phenomena · Physics 2018-10-31 Rahul Basu , Dipanjan Mitra , George I. Melikidze , Anna Skrzypczak

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

The unique and highly unusual drift feature reported for PSR J0815+0939, wherein one component's subpulses drift in the direction opposite of the general trend, is a veritable challenge to pulsar theory. In this paper, we observationally…

High Energy Astrophysical Phenomena · Physics 2019-08-27 Andrzej Szary , Joeri van Leeuwen

The number of pulsars with detected emission at X-ray and gamma-ray energies has been steadily growing, showing that beams of high-energy particles are commonly accelerated in pulsar magnetospheres, even though the location and number of…

Astrophysics · Physics 2009-11-11 Isabelle A. Grenier , Alice K. Harding
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