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Title: MAGNETAR FIELD EVOLUTION AND CRUSTAL PLASTICITY

Abstract

The activity of magnetars is believed to be powered by colossal magnetic energy reservoirs. We sketch an evolutionary picture in which internal field evolution in magnetars generates a twisted corona, from which energy may be released suddenly in a single giant flare, or more gradually through smaller outbursts and persistent emission. Given the ages of magnetars and the energy of their giant flares, we suggest that their evolution is driven by a novel mechanism: magnetic flux transport/decay due to persistent plastic flow in the crust, which would invalidate the common assumption that the crustal lattice is static and evolves only under Hall drift and Ohmic decay. We estimate the field strength required to induce plastic flow as a function of crustal depth, and the viscosity of the plastic phase. The star’s superconducting core may also play a role in magnetar field evolution, depending on the star’s spindown history and how rotational vortices and magnetic fluxtubes interact.

Authors:
 [1]
  1. Mathematical Sciences and STAG Research Centre, University of Southampton, Southampton SO17 1BJ (United Kingdom)
Publication Date:
OSTI Identifier:
22654296
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 824; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DECAY; EMISSION; MAGNETIC FIELDS; MAGNETIC FLUX; NEUTRON STARS; PLASTICITY; PLASTICS; VISCOSITY; VORTICES

Citation Formats

Lander, S. K., E-mail: skl@soton.ac.uk. MAGNETAR FIELD EVOLUTION AND CRUSTAL PLASTICITY. United States: N. p., 2016. Web. doi:10.3847/2041-8205/824/2/L21.
Lander, S. K., E-mail: skl@soton.ac.uk. MAGNETAR FIELD EVOLUTION AND CRUSTAL PLASTICITY. United States. https://doi.org/10.3847/2041-8205/824/2/L21
Lander, S. K., E-mail: skl@soton.ac.uk. 2016. "MAGNETAR FIELD EVOLUTION AND CRUSTAL PLASTICITY". United States. https://doi.org/10.3847/2041-8205/824/2/L21.
@article{osti_22654296,
title = {MAGNETAR FIELD EVOLUTION AND CRUSTAL PLASTICITY},
author = {Lander, S. K., E-mail: skl@soton.ac.uk},
abstractNote = {The activity of magnetars is believed to be powered by colossal magnetic energy reservoirs. We sketch an evolutionary picture in which internal field evolution in magnetars generates a twisted corona, from which energy may be released suddenly in a single giant flare, or more gradually through smaller outbursts and persistent emission. Given the ages of magnetars and the energy of their giant flares, we suggest that their evolution is driven by a novel mechanism: magnetic flux transport/decay due to persistent plastic flow in the crust, which would invalidate the common assumption that the crustal lattice is static and evolves only under Hall drift and Ohmic decay. We estimate the field strength required to induce plastic flow as a function of crustal depth, and the viscosity of the plastic phase. The star’s superconducting core may also play a role in magnetar field evolution, depending on the star’s spindown history and how rotational vortices and magnetic fluxtubes interact.},
doi = {10.3847/2041-8205/824/2/L21},
url = {https://www.osti.gov/biblio/22654296}, journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 2,
volume = 824,
place = {United States},
year = {Mon Jun 20 00:00:00 EDT 2016},
month = {Mon Jun 20 00:00:00 EDT 2016}
}