Bifurcation analysis of a two-dimensional magnetic Rayleigh–Bénard problem
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Author(s)
Laakmann, Fabian
Boullé, Nicolas
Type
Journal Article
Abstract
We perform a bifurcation analysis of a two-dimensional magnetic Rayleigh–Bénard problem using a numerical
technique called deflated continuation. Our aim is to study the influence of the magnetic field on the bifurcation
diagram as the Chandrasekhar number 𝑄 increases and compare it to the standard (non-magnetic) Rayleigh–
Bénard problem. We compute steady states at a high Chandrasekhar number of 𝑄 = 103 over a range of the
Rayleigh number 0 ≤ Ra ≤ 105
. These solutions are obtained by combining deflation with a continuation of
steady states at low Chandrasekhar number, which allows us to explore the influence of the strength of the
magnetic field as 𝑄 increases from low coupling, where the magnetic effect is almost negligible, to strong
coupling at 𝑄 = 103
. We discover a large profusion of states with rich dynamics and observe a complex
bifurcation structure with several pitchfork, Hopf, and saddle–node bifurcations. Our numerical simulations
show that the onset of bifurcations in the problem is delayed when 𝑄 increases, while solutions with fluid
velocity patterns aligning with the background vertical magnetic field are privileged. Additionally, we report
a branch of states that stabilizes at high magnetic coupling, suggesting that one may take advantage of the
magnetic field to discriminate solutions.
technique called deflated continuation. Our aim is to study the influence of the magnetic field on the bifurcation
diagram as the Chandrasekhar number 𝑄 increases and compare it to the standard (non-magnetic) Rayleigh–
Bénard problem. We compute steady states at a high Chandrasekhar number of 𝑄 = 103 over a range of the
Rayleigh number 0 ≤ Ra ≤ 105
. These solutions are obtained by combining deflation with a continuation of
steady states at low Chandrasekhar number, which allows us to explore the influence of the strength of the
magnetic field as 𝑄 increases from low coupling, where the magnetic effect is almost negligible, to strong
coupling at 𝑄 = 103
. We discover a large profusion of states with rich dynamics and observe a complex
bifurcation structure with several pitchfork, Hopf, and saddle–node bifurcations. Our numerical simulations
show that the onset of bifurcations in the problem is delayed when 𝑄 increases, while solutions with fluid
velocity patterns aligning with the background vertical magnetic field are privileged. Additionally, we report
a branch of states that stabilizes at high magnetic coupling, suggesting that one may take advantage of the
magnetic field to discriminate solutions.
Date Issued
2024-11
Date Acceptance
2024-06-17
Citation
Physica D: Nonlinear Phenomena, 2024, 467
ISSN
0167-2789
Publisher
Elsevier
Journal / Book Title
Physica D: Nonlinear Phenomena
Volume
467
Copyright Statement
© 2024 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
http://dx.doi.org/10.1016/j.physd.2024.134270
Publication Status
Published
Article Number
134270
Date Publish Online
2024-06-24