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Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/7500
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dc.contributor.authorJingade, Naveen-
dc.contributor.authorSingh, Nishant K.-
dc.date.accessioned2020-08-12T06:02:22Z-
dc.date.available2020-08-12T06:02:22Z-
dc.date.issued2020-07-
dc.identifier.citationMonthly Notices of the Royal Astronomical Society, 2020, Vol.495, p4557–4569en_US
dc.identifier.issn0035-8711-
dc.identifier.issn1365-2966 (online)-
dc.identifier.urihttp://hdl.handle.net/2289/7500-
dc.descriptionOpen Accessen_US
dc.description.abstractWe study mean field dynamo action in a background linear shear flow by employing pulsed renewing flows with fixed kinetic helicity and non-zero correlation time (τ). We use plane shearing waves in terms of time-dependent exact solutions to the Navier-Stokes equation as derived by Singh & Sridhar (2017). This allows us to self-consistently include the anisotropic effects of shear on the stochastic flow. We determine the average response tensor governing the evolution of mean magnetic field, and study the properties of its eigenvalues that yield the growth rate (γ) and the cycle period (Pcyc) of the mean magnetic field. Both, γ and the wavenumber corresponding to the fastest growing axisymmetric mode vary non-monotonically with shear rate S when τ is comparable to the eddy turnover time T, in which case, we also find quenching of dynamo when shear becomes too strong. When τ/T∼O(1) , the cycle period (Pcyc) of growing dynamo wave scales with shear as Pcyc ∝ |S|-1 at small shear, and it becomes nearly independent of shear as shear becomes too strong. This asymptotic behaviour at weak and strong shear has implications for magnetic activity cycles of stars in recent observations. Our study thus essentially generalizes the standard αΩ (or α2Ω) dynamo as also the α effect is affected by shear and the modelled random flow has a finite memory.en_US
dc.language.isoenen_US
dc.publisherOxford University Press on behalf of the Royal Astronomical Societyen_US
dc.relation.urihttps://ui.adsabs.harvard.edu/abs/2020MNRAS.495.4557J/abstracten_US
dc.relation.urihttps://arxiv.org/abs/1911.00235en_US
dc.relation.urihttps://doi.org/10.1093/mnras/staa1204en_US
dc.rights2020 The Author(s)en_US
dc.subjectdynamoen_US
dc.subjectmagnetic fieldsen_US
dc.subjectMHDen_US
dc.subjectplasmasen_US
dc.subjectturbulenceen_US
dc.subjectstars: activityen_US
dc.titleMean field dynamo action in shear flows. I: fixed kinetic helicityen_US
dc.typeArticleen_US
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