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dc.contributor.advisorParnell, Clare Elizabeth
dc.contributor.authorRestante, Anna Lisa
dc.coverage.spatial142en_US
dc.date.accessioned2011-12-12T15:00:47Z
dc.date.available2011-12-12T15:00:47Z
dc.date.issued2011-06-20
dc.identifier.urihttps://hdl.handle.net/10023/2106
dc.description.abstractThe structure of the magnetic field is often an important factor in many energetic processes in the solar corona. To determine the topology of the magnetic field features such as null points, separatrix surfaces, and separators must be found. It has been found that these features may be preferred sites for the formation of current sheets associated with the accumulation of free magnetic energy. Over the last decade, it also became clear that the geometrical analogs of the separatrices, the so-called quasi separatrix layers, have similar properties. This thesis has the aim of investigating these properties and to find correlations between these quantities. Our goal is to determine the relation between the geometrical features associated with the QSLs and with current structures, sites of reconnection and topological features. With these aims we conduct three different studies. First, we investigate a non linear force free magnetic field extrapolation from observed magnetogram data taken during a solar flare eruption concentrating our attention on two snapshots, one before the event and one after. We determine the QSLs and related structures and by considering carefully how these change between the two snapshots we are able to propose a possible scenario for how the flare occurred. In our second project we consider potential source distributions. We take different potential point source models: two four sources models already presented in the literature and a random distribution of fifteen sources. From these potential models we conduct a detailed analysis of the relationship between topological features and QSLs. It is found that the maxima of the Q-factor in the photosphere are located near and above the position of the subphotospheric null points (extending part way along their spines) and that their narrow QSLs are associated with the curves defined by the photospheric endpoints of all fan field lines that start from subphotospheric sources. Our last study investigates two different flux rope emergence simulations. In particular, we take one case with and one without an overlying magnetic field. Here, we can identify the QSLs, current, and sites of reconnection and determine the relation between them. From this work we found that not all high-Q regions are associated with current and/or reconnection and vice-versa. We also investigated the geometry of the field lines associated with high-Q regions to determine which geometrical behaviour of the magnetic field they are associated with. Those that are associated with reconnection also coincide with topological features such as separators.en_US
dc.language.isoenen_US
dc.publisherUniversity of St Andrews
dc.rightsCreative Commons Attribution 3.0 Unported
dc.rights.urihttp://creativecommons.org/licenses/by/3.0/
dc.subjectSolar physicsen_US
dc.subjectQuasi-separatrix layers (QSLs)en_US
dc.subjectMagnetic field topologyen_US
dc.subjectReconnectionen_US
dc.subject.lccQB539.M23R4
dc.subject.lcshSolar magnetic fields--Mathematical modelsen_US
dc.subject.lcshMagnetic reconnectionen_US
dc.subject.lcshForce-free magnetic fieldsen_US
dc.titleThe investigation of quasi-separatrix layers in solar magnetic fieldsen_US
dc.typeThesisen_US
dc.contributor.sponsorSOLAIRE European Research Training Networken_US
dc.type.qualificationlevelDoctoralen_US
dc.type.qualificationnamePhD Doctor of Philosophyen_US
dc.publisher.institutionThe University of St Andrewsen_US
dc.publisher.departmentObservatoire de Parisen_US


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Creative Commons Attribution 3.0 Unported
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