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dc.contributor.advisorHood, Alan W.
dc.contributor.authorLothian, Robert M.
dc.coverage.spatial150 p.en_US
dc.description.abstractUsing the Magnetohydrodynamic model, two problems in the behaviour of magnetic field structures are investigated. Firstly, the stability of tokamak equilibria to coupled tearing modes is calculated. Secondly, the equilibrium structure of a solar coronal loop is examined. The flux co-ordinate method is used to construct toroidal equilibria of the type found in large aspect ratio tokamaks. In such a field configuration, the analysis of tearing modes is complicated by the coupling of different poloidal fourier modes. The effect of coupling through elliptic shaping of plasma surfaces is calculated. For certain current profiles, this effect may cause instability. The response of coronal loops to twisting at their photospheric footpoints is investigated. Long loops are shown to have an essentially 1-D nature. This observation is used to develop a 1-D, line-tied model for such loops. This model is used to conduct an extensive survey of the non-linear twist regime, including the effects of enhanced fluid pressure. The possibility of non-equilibrium, which would provide energy for coronal heating and compact flares, is examined. When the physical variable of footpoint displacement is specified, no loss of equilibrium is found by twisting. Loss of equilibrium is found for high pressures, which we do not, however, expect to find in the corona.en_US
dc.publisherUniversity of St Andrewsen
dc.titleAspects of magnetic field theory in solar and laboratory plasmasen_US
dc.contributor.sponsorScience and Engineering Research Council (SERC)en_US
dc.contributor.sponsorAEA Technology Culhamen_US
dc.type.qualificationnamePhD Doctor of Philosophyen_US
dc.publisher.institutionThe University of St Andrewsen_US
dc.publisher.departmentCulham Laboratoryen_US

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