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Magnetars have inferred polar field strengths in excess of the Schwinger limit, where non-linear electromagnetic effects can be significant. Their internal fields may be even stronger, suggesting that Maxwellian characterizations of…

High Energy Astrophysical Phenomena · Physics 2025-05-12 Arthur G. Suvorov , José A. Pons

A new code for computing fully general relativistic solutions of strongly magnetized rapidly rotating compact stars is developed as a part of the COCAL (Compact Object CALculator) code. The full set of Einstein's equations, Maxwell's…

General Relativity and Quantum Cosmology · Physics 2019-12-25 Koji Uryu , Shijun Yoshida , Eric Gourgoulhon , Charalampos Markakis , Kotaro Fujisawa , Antonios Tsokaros , Keisuke Taniguchi , Yoshiharu Eriguchi

In this third paper in a series on stable magnetic equilibria in stars, I look at the stability of axisymmetric field configurations and in particular at the relative strengths of the toroidal and poloidal components. Both toroidal and…

Astrophysics · Physics 2015-05-13 J. Braithwaite

(Abridged) We develop a theoretical framework to construct axisymmetric magnetic equilibria in stars, consisting of both poloidal and toroidal magnetic field components. In a stationary axisymmetric configuration, the poloidal current is a…

Solar and Stellar Astrophysics · Physics 2015-05-13 Maxim Lyutikov

We have succeeded in obtaining magnetized equilibrium states with differential rotation and differential toroidal magnetic fields. If an internal toroidal field of a proto-neutron star is wound up from the initial poloidal magnetic field by…

High Energy Astrophysical Phenomena · Physics 2015-08-28 Kotaro Fujisawa

Using an axisymmetric numerical code, we perform an extensive study of the magnetic field configurations in non-rotating neutron stars, varying the mass, magnetic field strength and the equation of state. We find that the monopolar…

Nuclear Theory · Physics 2019-06-12 Debarati Chatterjee , Jerome Novak , Micaela Oertel

As another step towards understanding the long-term evolution of the magnetic field in neutron stars, we provide the first simulations of ambipolar diffusion in a spherical star. Restricting ourselves to axial symmetry, we consider a…

High Energy Astrophysical Phenomena · Physics 2017-07-17 F. Castillo , A. Reisenegger , J. A. Valdivia

We investigate the instability of purely poloidal magnetic fields in nonrotating neutron stars by means of three-dimensional general-relativistic magnetohydrodynamics simulations, extending the work presented in Ciolfi et al. (2011). Our…

Solar and Stellar Astrophysics · Physics 2015-06-05 Riccardo Ciolfi , Luciano Rezzolla

We solve the Einstein-Maxwell-Klein-Gordon system of equations and derive a compact, static axially symmetric magnetized object which is electrically neutral and made of two complex massive charged scalar fields. We describe several…

General Relativity and Quantum Cosmology · Physics 2022-11-23 Víctor Jaramillo , Darío Núñez

A method for mapping known cylindrical magnetovac solutions to solutions in torus coordinates is developed. Identification of the cylinder ends changes topology from R1 x S1 to S1 x S1. An analytic Einstein-Maxwell solution for a toroidal…

General Relativity and Quantum Cosmology · Physics 2009-11-11 E. N. Glass

The phenomenology of the emission of pulsars and magnetars depends dramatically on the structure and properties of their magnetic field. In particular it is believed that the outbursting and flaring activity observed in AXPs and SRGs is…

High Energy Astrophysical Phenomena · Physics 2016-06-22 N. Bucciantini , A. G. Pili , L. Del Zanna

We obtained the magnetic field configurations, including both poloidal and toroidal components, throughout the interior and exterior of magnetars using a realistic equation of state. We divided the magnetized star into the hydromagnetic…

High Energy Astrophysical Phenomena · Physics 2015-10-01 Kotaro Fujisawa , Shota Kisaka

The origin of magnetic fields in the universe still remains unknown and constitutes one of the most intriguing questions in astronomy and astrophysics. Their significance is enormous since they have a strong influence on many astrophysical…

General Relativity and Quantum Cosmology · Physics 2018-06-13 Anamaría Navarro-Noguera , F. D. Lora-Clavijo , Guillermo A. González

Although barotropic matter does not constitute a realistic model for magnetic stars, it would be interesting to confirm a recent conjecture that states that magnetized stars with a barotropic equation of state would be dynamically unstable…

Solar and Stellar Astrophysics · Physics 2015-06-15 Cristobal Armaza , Andreas Reisenegger , Juan Alejandro Valdivia , Pablo Marchant

We adapt the well known "displace, cut and reflect" method to construct exact solutions of the Einstein-Maxwell equations corresponding to infinitesimally thin disks of matter endowed with dipole magnetic fields, which are entirely…

General Relativity and Quantum Cosmology · Physics 2017-07-04 Vanessa P. de Freitas , Alberto Saa

Applying the Horsk\'y-Mitskievitch conjecture to the empty space solutions of Morgan and Morgan due to the gravitational field of a finite disk, we have obtained the corresponding solutions of the Einstein-Maxwell equations. The resulting…

General Relativity and Quantum Cosmology · Physics 2015-05-20 Antonio C. Gutiérrez-Piñeres , Guillermo A. González

Magnetic fields play a crucial role in many astrophysical scenarios and, in particular, are of paramount importance in the emission mechanism and evolution of Neutron Stars (NSs). To understand the role of the magnetic field in compact…

High Energy Astrophysical Phenomena · Physics 2015-06-18 A. G. Pili , N. Bucciantini , L. Del Zanna

We present three-dimensional force-free electrodynamics simulations of magnetar magnetospheres that demonstrate the instability of certain degenerate, high energy equilibrium solutions of the Grad-Shafranov equation. This result indicates…

High Energy Astrophysical Phenomena · Physics 2019-11-26 J. F. Mahlmann , T. Akgün , J. A. Pons , M. A. Aloy , P. Cerdá-Durán

The magnetar magnetosphere is gradually twisted by shearing from footpoint motion, and stored magnetic energy also increases at the same time. When a state exceeds a threshold, flares/outbursts manifest themselves as a result of a…

High Energy Astrophysical Phenomena · Physics 2018-04-25 Yasufumi Kojima

In the absence of an active dynamo, purely poloidal magnetic field configurations are unstable to large-scale dynamical perturbations, and decay via reconnection on an Alfvenic timescale. Nevertheless, a number of classes of dynamo-free…

Astrophysics · Physics 2009-11-13 Avery E. Broderick , Ramesh Narayan