Asymptotic, non-linear solutions for ambipolar diffusion in one dimension

Jaime H. Hoyos, Andreas Reisenegger, Juan A. Valdivia

Resultado de la investigación: Contribución a una revistaArtículo

13 Citas (Scopus)

Resumen

We study the effect of the non-linear process of ambipolar diffusion (joint transport of magnetic flux and charged particles relative to neutral particles) on the long-term behaviour of a non-uniform magnetic field in a one-dimensional geometry. Our main focus is the dissipation of magnetic energy inside neutron stars (particularly magnetars), but our results have a wider application, particularly to the interstellar medium and the loss of magnetic flux from collapsing molecular cloud cores. Our system is a weakly ionized plasma in which neutral and charged particles can be converted into each other through nuclear beta decays (or ionization-recombination processes). In the 'weak-coupling' limit of infrequent inter-particle interactions, the evolution of the magnetic field is controlled by the beta decay rate and can be described by a non-linear partial integro-differential equation. In the opposite, 'strong-coupling' regime, the evolution is controlled by the inter-particle collisions and can be modelled through a non-linear diffusion equation. We show numerically that, in both regimes, ambipolar diffusion tends to spread out the magnetic flux, but, contrary to the normal Ohmic diffusion, it produces sharp magnetic-field gradients with associated current sheets around those regions where the magnetic field is weak. © 2010 The Authors. Journal compilation © 2010 RAS.
Idioma originalInglés estadounidense
Páginas (desde-hasta)1730-1741
Número de páginas12
PublicaciónMonthly Notices of the Royal Astronomical Society
Volumen408
N.º3
DOI
EstadoPublicada - 1 nov 2010

Huella dactilar

ambipolar diffusion
magnetic flux
neutral particles
charged particles
magnetic field
magnetic fields
nonuniform magnetic fields
magnetars
particle collisions
current sheets
particle interactions
molecular clouds
partial differential equations
neutron stars
decay rates
dissipation
ionization
gradients
recombination
decay

Citar esto

Hoyos, Jaime H. ; Reisenegger, Andreas ; Valdivia, Juan A. / Asymptotic, non-linear solutions for ambipolar diffusion in one dimension. En: Monthly Notices of the Royal Astronomical Society. 2010 ; Vol. 408, N.º 3. pp. 1730-1741.
@article{deefb82aa70348cd9228222a19b72d4a,
title = "Asymptotic, non-linear solutions for ambipolar diffusion in one dimension",
abstract = "We study the effect of the non-linear process of ambipolar diffusion (joint transport of magnetic flux and charged particles relative to neutral particles) on the long-term behaviour of a non-uniform magnetic field in a one-dimensional geometry. Our main focus is the dissipation of magnetic energy inside neutron stars (particularly magnetars), but our results have a wider application, particularly to the interstellar medium and the loss of magnetic flux from collapsing molecular cloud cores. Our system is a weakly ionized plasma in which neutral and charged particles can be converted into each other through nuclear beta decays (or ionization-recombination processes). In the 'weak-coupling' limit of infrequent inter-particle interactions, the evolution of the magnetic field is controlled by the beta decay rate and can be described by a non-linear partial integro-differential equation. In the opposite, 'strong-coupling' regime, the evolution is controlled by the inter-particle collisions and can be modelled through a non-linear diffusion equation. We show numerically that, in both regimes, ambipolar diffusion tends to spread out the magnetic flux, but, contrary to the normal Ohmic diffusion, it produces sharp magnetic-field gradients with associated current sheets around those regions where the magnetic field is weak. {\circledC} 2010 The Authors. Journal compilation {\circledC} 2010 RAS.",
author = "Hoyos, {Jaime H.} and Andreas Reisenegger and Valdivia, {Juan A.}",
year = "2010",
month = "11",
day = "1",
doi = "10.1111/j.1365-2966.2010.17237.x",
language = "American English",
volume = "408",
pages = "1730--1741",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "3",

}

Asymptotic, non-linear solutions for ambipolar diffusion in one dimension. / Hoyos, Jaime H.; Reisenegger, Andreas; Valdivia, Juan A.

En: Monthly Notices of the Royal Astronomical Society, Vol. 408, N.º 3, 01.11.2010, p. 1730-1741.

Resultado de la investigación: Contribución a una revistaArtículo

TY - JOUR

T1 - Asymptotic, non-linear solutions for ambipolar diffusion in one dimension

AU - Hoyos, Jaime H.

AU - Reisenegger, Andreas

AU - Valdivia, Juan A.

PY - 2010/11/1

Y1 - 2010/11/1

N2 - We study the effect of the non-linear process of ambipolar diffusion (joint transport of magnetic flux and charged particles relative to neutral particles) on the long-term behaviour of a non-uniform magnetic field in a one-dimensional geometry. Our main focus is the dissipation of magnetic energy inside neutron stars (particularly magnetars), but our results have a wider application, particularly to the interstellar medium and the loss of magnetic flux from collapsing molecular cloud cores. Our system is a weakly ionized plasma in which neutral and charged particles can be converted into each other through nuclear beta decays (or ionization-recombination processes). In the 'weak-coupling' limit of infrequent inter-particle interactions, the evolution of the magnetic field is controlled by the beta decay rate and can be described by a non-linear partial integro-differential equation. In the opposite, 'strong-coupling' regime, the evolution is controlled by the inter-particle collisions and can be modelled through a non-linear diffusion equation. We show numerically that, in both regimes, ambipolar diffusion tends to spread out the magnetic flux, but, contrary to the normal Ohmic diffusion, it produces sharp magnetic-field gradients with associated current sheets around those regions where the magnetic field is weak. © 2010 The Authors. Journal compilation © 2010 RAS.

AB - We study the effect of the non-linear process of ambipolar diffusion (joint transport of magnetic flux and charged particles relative to neutral particles) on the long-term behaviour of a non-uniform magnetic field in a one-dimensional geometry. Our main focus is the dissipation of magnetic energy inside neutron stars (particularly magnetars), but our results have a wider application, particularly to the interstellar medium and the loss of magnetic flux from collapsing molecular cloud cores. Our system is a weakly ionized plasma in which neutral and charged particles can be converted into each other through nuclear beta decays (or ionization-recombination processes). In the 'weak-coupling' limit of infrequent inter-particle interactions, the evolution of the magnetic field is controlled by the beta decay rate and can be described by a non-linear partial integro-differential equation. In the opposite, 'strong-coupling' regime, the evolution is controlled by the inter-particle collisions and can be modelled through a non-linear diffusion equation. We show numerically that, in both regimes, ambipolar diffusion tends to spread out the magnetic flux, but, contrary to the normal Ohmic diffusion, it produces sharp magnetic-field gradients with associated current sheets around those regions where the magnetic field is weak. © 2010 The Authors. Journal compilation © 2010 RAS.

U2 - 10.1111/j.1365-2966.2010.17237.x

DO - 10.1111/j.1365-2966.2010.17237.x

M3 - Article

VL - 408

SP - 1730

EP - 1741

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 3

ER -