Determination of the Analytical Solutions of the Radio Emission Geometry and Polar Cap Structure of Pulsars Having Perturbed Dipole

We model an analytical solution to generate the shape of the polar cap structure and discuss the geometrical distortion due to the presence of both longitudinal plasma current flow across the polar cap regime, i.e., polar cap current perturbation, and pulsar rotation, i.e., rotational perturbation....

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Main Authors: Tridib Roy, Mageshwaran Tamilan, Ramkrishna Das
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ad9f2a
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author Tridib Roy
Mageshwaran Tamilan
Ramkrishna Das
author_facet Tridib Roy
Mageshwaran Tamilan
Ramkrishna Das
author_sort Tridib Roy
collection DOAJ
description We model an analytical solution to generate the shape of the polar cap structure and discuss the geometrical distortion due to the presence of both longitudinal plasma current flow across the polar cap regime, i.e., polar cap current perturbation, and pulsar rotation, i.e., rotational perturbation. An analytical solution to the parameter space associated with the radio emission geometrical coordinate is produced by using the first- and second-order power series expansion method for the rotationally perturbed dipole case. In general, polar caps show a quasi-elliptical shape, but in the presence of higher-order plasma current our results show that they can be converted into an elliptical structure with a monotonically reduced dimension. Our results show that the rotational effect also leads to a contraction of the dimensions of the polar cap for a given range of the obliquity parameters. We have found that the last open field line constant, as a fraction of the light cylinder radius, decreases in the presence of nonzero plasma current discharge. We also demonstrate that under certain conditions introducing a higher-order plasma current (e.g., with a scale factor ζ _p = J / J _GJ close to 1 in the closed field line region) can lead to a structure resembling a cosmic-combed magnetosphere.
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spelling doaj-art-e5924c4f156640b28688068fa74648a62025-02-05T10:07:28ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198016510.3847/1538-4357/ad9f2aDetermination of the Analytical Solutions of the Radio Emission Geometry and Polar Cap Structure of Pulsars Having Perturbed DipoleTridib Roy0https://orcid.org/0000-0002-6088-5520Mageshwaran Tamilan1https://orcid.org/0000-0002-6187-4073Ramkrishna Das2https://orcid.org/0000-0002-5440-7186Department of Astrophysics and High Energy Physics, SN Bose National Center For Basic Science , Salt Lake, Sector 3, JD Block, Kolkata 700106, India ; tridibroy.12@gmail.com, tridibroy@bose.res.inDepartment of Space Science and Astronomy, Chungbuk National University , Cheongju 361-763, South KoreaDepartment of Astrophysics and High Energy Physics, SN Bose National Center For Basic Science , Salt Lake, Sector 3, JD Block, Kolkata 700106, India ; tridibroy.12@gmail.com, tridibroy@bose.res.inWe model an analytical solution to generate the shape of the polar cap structure and discuss the geometrical distortion due to the presence of both longitudinal plasma current flow across the polar cap regime, i.e., polar cap current perturbation, and pulsar rotation, i.e., rotational perturbation. An analytical solution to the parameter space associated with the radio emission geometrical coordinate is produced by using the first- and second-order power series expansion method for the rotationally perturbed dipole case. In general, polar caps show a quasi-elliptical shape, but in the presence of higher-order plasma current our results show that they can be converted into an elliptical structure with a monotonically reduced dimension. Our results show that the rotational effect also leads to a contraction of the dimensions of the polar cap for a given range of the obliquity parameters. We have found that the last open field line constant, as a fraction of the light cylinder radius, decreases in the presence of nonzero plasma current discharge. We also demonstrate that under certain conditions introducing a higher-order plasma current (e.g., with a scale factor ζ _p = J / J _GJ close to 1 in the closed field line region) can lead to a structure resembling a cosmic-combed magnetosphere.https://doi.org/10.3847/1538-4357/ad9f2aRadio pulsars
spellingShingle Tridib Roy
Mageshwaran Tamilan
Ramkrishna Das
Determination of the Analytical Solutions of the Radio Emission Geometry and Polar Cap Structure of Pulsars Having Perturbed Dipole
The Astrophysical Journal
Radio pulsars
title Determination of the Analytical Solutions of the Radio Emission Geometry and Polar Cap Structure of Pulsars Having Perturbed Dipole
title_full Determination of the Analytical Solutions of the Radio Emission Geometry and Polar Cap Structure of Pulsars Having Perturbed Dipole
title_fullStr Determination of the Analytical Solutions of the Radio Emission Geometry and Polar Cap Structure of Pulsars Having Perturbed Dipole
title_full_unstemmed Determination of the Analytical Solutions of the Radio Emission Geometry and Polar Cap Structure of Pulsars Having Perturbed Dipole
title_short Determination of the Analytical Solutions of the Radio Emission Geometry and Polar Cap Structure of Pulsars Having Perturbed Dipole
title_sort determination of the analytical solutions of the radio emission geometry and polar cap structure of pulsars having perturbed dipole
topic Radio pulsars
url https://doi.org/10.3847/1538-4357/ad9f2a
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AT mageshwarantamilan determinationoftheanalyticalsolutionsoftheradioemissiongeometryandpolarcapstructureofpulsarshavingperturbeddipole
AT ramkrishnadas determinationoftheanalyticalsolutionsoftheradioemissiongeometryandpolarcapstructureofpulsarshavingperturbeddipole