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Title: A model for the solar dynamo driven by magnetic buoyancy
Author: Davies, Cristina Ruth
ISNI:       0000 0004 2724 3344
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2011
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The problem of generation and maintenance of the solar magnetic field has already been studied in detail, with many studies concentrating on kinematic, convection-driven dynamos. These have, in many cases, been unable to create and sustain a large-scale magnetic field in the parameter regimes required for accurate modelling of the solar interior. This thesis addresses the possibility of an alternative dynamo mechanism, powered by the magnetic buoyancy instability. Such a mechanism is dynamic, rather than kinematic, in nature and as such the electromotive force (emf), which is an averaged product of perturbations, is fully dependent on the form of the field. In this thesis we begin by considering some of the earliest studies of magnetic buoyancy, in particular that of Gilman (1970). The system of perturbation equations from this paper is used to derive an analytical expression for the emf. The large-wavelength limit used in this paper is then examined and the eigenfunctions of a simplified system of perturbation ... '. ~ equations are found to localise in this limit. The emfs resulting from atmospheres unstable to magnetic buoyancy are then numerically calculated using the method of inverse iteration. The symmetries of the emfs and their dependence on the governing parameters of the problem are then studied; finally a sheared component of magnetic field is introduced. This breaks some of the previously existing symmetries of the system and allows us to study the nature of the instability when it must 'untwist' the field in order to propagate.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available