Open AccessDiamagnetic screening of the magnetic field in accreting neutron stars
Author(s) -
Rai Choudhuri Arnab,
Konar Sushan
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.05362.x
Subject(s) - physics , neutron star , diamagnetism , astrophysics , accretion (finance) , magnetic field , buoyancy , magnetohydrodynamics , field (mathematics) , mechanics , mathematics , quantum mechanics , pure mathematics
A possible mechanism for screening of the surface magnetic field of an accreting neutron star, by the accreted material, is investigated. We model the material flow in the surface layers of the star by an assumed two‐dimensional velocity field satisfying all the physical requirements. Using this model velocity we find that, in the absence of magnetic buoyancy, the surface field is screened (i.e. there is submergence of the field by advection) within the time‐scale of material flow of the top layers. On the other hand, if magnetic buoyancy is present, the screening happens over a time‐scale that is characteristic of the slower flow of the deeper (and hence, denser) layers. For accreting neutron stars, this longer time‐scale turns out to be about 10 5 yr, which is of a similar order of magnitude to the accretion time‐scale of most massive X‐ray binaries.