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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Large-scale weakly nonlinear perturbations of convective magnetic dynamos in a rotating layer

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Chertovskih, R. [1] ; Zheligovsky, V. [2]
Número total de Autores: 2
Afiliação do(s) autor(es):
[1] Inst Aeronaut Technol, BR-12228900 Sao Jose Dos Campos, SP - Brazil
[2] Russian Acad Sci, Inst Earthquake Predict Theory & Math Geophys, Moscow 117997 - Russia
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: PHYSICA D-NONLINEAR PHENOMENA; v. 313, p. 99-116, DEC 1 2015.
Citações Web of Science: 3

We present a new mechanism for generation of large-scale magnetic field by thermal convection which does not involve the a-effect. We consider weakly nonlinear perturbations of space-periodic steady convective magnetic dynamos in a rotating layer of incompressible electrically conducting fluid that were identified in our previous work. The perturbations have a spatial scale in the horizontal direction that is much larger than the period of the perturbed convective magnetohydrodynamic state. Following the formalism of the multiscale stability theory, we have derived the system of amplitude equations governing the evolution of the leading terms in the expansion of the perturbations in power series in the scale ratio. This asymptotic analysis is more involved than in the cases considered earlier, because the kernel of the operator of linearisation has zero-mean neutral modes whose origin lies in the spatial invariance of the perturbed regime, the operator reduced on the generalised kernel has two Jordan normal form blocks of size two, and simplifying symmetries of the perturbed state are now missing. Numerical results for the amplitude equations show that a large-scale perturbation, periodic in slow horizontal variable, either converges to a small-scale neutral stability mode with amplitudes tending to constant values, or it blows up at a finite slow time. (C) 2015 Elsevier B.V. All rights reserved. (AU)

Processo FAPESP: 13/01242-8 - Geração de campos magnéticos de grandes escalas por convecção de Rayleigh-Bénard
Beneficiário:Roman Chertovskikh
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado