Triggering magnetar outbursts in 3D force-free simulations
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http://hdl.handle.net/10045/89608
Títol: | Triggering magnetar outbursts in 3D force-free simulations |
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Autors: | Carrasco, Federico | Viganò, Daniele | Palenzuela, Carlos | Pons, José A. |
Grups d'investigació o GITE: | Astrofísica Relativista |
Centre, Departament o Servei: | Universidad de Alicante. Departamento de Física Aplicada |
Paraules clau: | Plasmas | Magnetic reconnection | Stars: magnetars | Stars: magnetic field | Stars: flares | Methods: numerical |
Àrees de coneixement: | Astronomía y Astrofísica |
Data de publicació: | 21-de març-2019 |
Editor: | Oxford University Press |
Citació bibliogràfica: | Monthly Notices of the Royal Astronomical Society. 2019, 484(1): L124-L129. doi:10.1093/mnrasl/slz016 |
Resum: | In this letter, we present the first 3D force-free general relativity simulations of the magnetosphere dynamics related to the magnetar outburst/flare phenomenology. Starting from an initial dipole configuration, we adiabatically increase the helicity by twisting the footprints of a spot on the stellar surface and follow the succession of quasi-equilibrium states until a critical twist is reached. Twisting beyond that point triggers instabilities that results in the rapid expansion of magnetic field lines, followed by reconnection, as observed in previous axi-symmetric simulations. If the injection of magnetic helicity goes on, the process is recurrent, periodically releasing a similar amount of energy, of the order of a few per cent of the total magnetic energy. From our current distribution, we estimate the local temperature assuming that dissipation occurs mainly in the highly resistive outermost layer of the neutron star. We find that the temperature smoothly increases with injected twist, being larger for spots located in the tropical regions than in polar regions, and rather independent of their sizes. After the injection of helicity ceases, the magnetosphere relaxes to a new stable state, in which the persistent currents maintain the footprints area slightly hotter than before the onset of the instability. |
Patrocinadors: | We acknowledge support from the Spanish Ministry of Economy, Industry, and Competitiveness grants AYA2016-80289-P and AYA2017-82089-ERC (AEI/FEDER, UE), and AYA2015-66899-C2-2-P. CP also acknowledges support from the Spanish Ministry of Education and Science through a Ramon y Cajal grant. |
URI: | http://hdl.handle.net/10045/89608 |
ISSN: | 0035-8711 (Print) | 1365-2966 (Online) |
DOI: | 10.1093/mnrasl/slz016 |
Idioma: | eng |
Tipus: | info:eu-repo/semantics/article |
Drets: | © 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society |
Revisió científica: | si |
Versió de l'editor: | https://doi.org/10.1093/mnrasl/slz016 |
Apareix a la col·lecció: | INV - Astrofísica Relativista - Artículos de Revistas |
Arxius per aquest ítem:
Arxiu | Descripció | Tamany | Format | |
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2019_Carrasco_etal_MNRAS.pdf | 2,03 MB | Adobe PDF | Obrir Vista prèvia | |
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