TY - JOUR
T1 - Homopolar oscillating-disc dynamo driven by parametric resonance
AU - Priede, Janis
AU - Avalos-Zuñiga, Raúl
AU - Plunian, Franck
PY - 2010/1/11
Y1 - 2010/1/11
N2 - We use a simple model of Bullard-type disc dynamo, in which the disc rotation rate is subject to harmonic oscillations, to analyze the generation of magnetic field by the parametric resonance mechanism. The problem is governed by a damped Mathieu equation. The Floquet exponents, which define the magnetic field growth rates, are calculated depending on the amplitude and frequency of the oscillations. Firstly, we show that the dynamo can be excited at significantly subcritical disc rotation rate when the latter is subject to harmonic oscillations with a certain frequency. Secondly, at supercritical mean rotation rates, the dynamo can also be suppressed but only in narrow frequency bands and at sufficiently large oscillation amplitudes.
AB - We use a simple model of Bullard-type disc dynamo, in which the disc rotation rate is subject to harmonic oscillations, to analyze the generation of magnetic field by the parametric resonance mechanism. The problem is governed by a damped Mathieu equation. The Floquet exponents, which define the magnetic field growth rates, are calculated depending on the amplitude and frequency of the oscillations. Firstly, we show that the dynamo can be excited at significantly subcritical disc rotation rate when the latter is subject to harmonic oscillations with a certain frequency. Secondly, at supercritical mean rotation rates, the dynamo can also be suppressed but only in narrow frequency bands and at sufficiently large oscillation amplitudes.
KW - Dynamo effect
KW - Instability
KW - Magnetohydrodynamics
KW - Mathieu equation
KW - Parametric resonance
UR - http://www.scopus.com/inward/record.url?scp=73149113052&partnerID=8YFLogxK
U2 - 10.1016/j.physleta.2009.11.022
DO - 10.1016/j.physleta.2009.11.022
M3 - Artículo
SN - 0375-9601
VL - 374
SP - 584
EP - 587
JO - Physics Letters, Section A: General, Atomic and Solid State Physics
JF - Physics Letters, Section A: General, Atomic and Solid State Physics
IS - 4
ER -