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Title: High resolution wave signatures in the magnetic solar atmosphere
Author: Grant, Samuel David Taylor
ISNI:       0000 0004 6421 4382
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2017
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This thesis concerns the study of energetic MHD waves in the solar atmosphere using high- resolution observations from the Dunn Solar Telescope, New Mexico, USA. The purpose of this study is to provide a greater understanding of the mechanisms that heat the upper solar atmosphere to temperatures ~ 1 million K above the solar surface. Compressible sausage modes are studied in magnetic pores as candidates for energy transport through the lower solar atmosphere. For the first time, sausage mode waves are shown to propagate from the solar surface into higher regions, exhibiting a reduction in wave energy that indicates that they may contribute to the enhanced heating of the upper solar atmosphere. Alongside this, the first verification of surface and body modes of sausage waves is made through the study of 7 photospheric pores. The surface modes are more prevalent than the body modes, which exist only in smaller, less magnetic pores. The surface modes also exhibit greater energies than the body modes. In addition to this, the effects of waves that steepen into plasma shocks in the centre of sunspots were studied. The high-resolution data on offer allowed for an unprecedented study of the heating potential of these Umbral Flashes using magnetic field extrapolations and thermal inversions. Two populations of shocks were identified, one close to spot centre and the other in more inclined fields, and it was shown that shocks formed in more magnetic regions were more efficient heaters of local plasma. Their complex motions were also seen to not be related to large scale magnetic configurations, indicating that behaviour below the resolution of the data is present. This thesis provides evidence to further the hypothesis that waves have a part in both energy transport and dissipation into heat in the upper solar atmosphere.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available