TY - JOUR
T1 - Convective quenching of field reversals in accretion disc dynamos
AU - Coleman, Matthew S.B.
AU - Yerger, Evan
AU - Blaes, Omer
AU - Salvesen, Greg
AU - Hirose, Shigenobu
N1 - Publisher Copyright:
© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
PY - 2017/6/1
Y1 - 2017/6/1
N2 - Vertically stratified shearing box simulations of magnetorotational turbulence commonly exhibit a so-called butterfly diagram of quasi-periodic azimuthal field reversals. However, in the presence of hydrodynamic convection, field reversals no longer occur. Instead, the azimuthal field strength fluctuates quasi-periodically while maintaining the same polarity, which can either be symmetric or antisymmetric about the disc mid-plane. Using data from the simulations of Hirose et al., we demonstrate that the lack of field reversals in the presence of convection is due to hydrodynamic mixing of magnetic field from the more strongly magnetized upper layers into the mid-plane, which then annihilate field reversals that are starting there. Our convective simulations differ in several respects from those reported in previous work by others, in which stronger magnetization likely plays a more important role than convection.
AB - Vertically stratified shearing box simulations of magnetorotational turbulence commonly exhibit a so-called butterfly diagram of quasi-periodic azimuthal field reversals. However, in the presence of hydrodynamic convection, field reversals no longer occur. Instead, the azimuthal field strength fluctuates quasi-periodically while maintaining the same polarity, which can either be symmetric or antisymmetric about the disc mid-plane. Using data from the simulations of Hirose et al., we demonstrate that the lack of field reversals in the presence of convection is due to hydrodynamic mixing of magnetic field from the more strongly magnetized upper layers into the mid-plane, which then annihilate field reversals that are starting there. Our convective simulations differ in several respects from those reported in previous work by others, in which stronger magnetization likely plays a more important role than convection.
KW - Accretion
KW - Accretion discs
KW - Convection
KW - Dynamo
KW - MHD
KW - Stars: dwarf novae
KW - Turbulence
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U2 - 10.1093/mnras/stx268
DO - 10.1093/mnras/stx268
M3 - Article
AN - SCOPUS:85085953622
SN - 0035-8711
VL - 467
SP - 2625
EP - 2635
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -