Bate, William (2019) Excitation of sausage oscillations in a curved coronal loop. PhD thesis, University of Warwick.

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Abstract

This thesis concerns itself with the effects of curvature in the modelling of fast magnetoacoustic sausage oscillations of coronal loops. The Lare2d code was used in order to solve the normalised magnetohydrodynamic (MHD) equations, providing an environment in which the numerical simulations could be performed. An initial plasma set-up was created in order to approximate a coronal loop as a curved magnetic slab. This initial state was then allowed to relax to an equilibrium state, which fast magnetoacoustic sausage oscillations could then be excited in. These oscillations were excited by a velocity pulse and their frequencies and periods measured. A parametric study was conducted by running sixteen numerical experiments with a range of physical parameters in the equilibrium state. The parameters investigated were the minor radius of the curved coronal slab, and the density ratio between the internal and external plasma, with all other properties kept constant. The results of these numerical experiments using a curved slab were then compared with the analytical results for a straight slab with the same properties. Within sufficiently dense and thick slabs, it was found that there was no measurable difference of the period of trapped sausage oscillations between the straight and curved slab models. However, there was a difference of approximately 10% found when modelling trapped sausage oscillations in thicker and less dense curved coronal slabs when compared to the analytical results from the straight slab model. The code used to perform these numerical experiments has been designed to be fully customisable. This is intended to facilitate further studies to be performed that account for the effects of curvature in the modelling of coronal loops.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	Q Science > QC Physics
Library of Congress Subject Headings (LCSH):	Oscillations, Sun -- Corona, Solar oscillations, Magnetohydrodynamics
Official Date:	December 2019
Dates:	Date Event December 2019 UNSPECIFIED
Institution:	University of Warwick
Theses Department:	Department of Physics
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Nakariakov, V. M. (Valery M.) ; Kolotkov, Dmitrii ; Goddard, Christopher R.
Format of File:	pdf
Extent:	viii, 42 leaves : illustrations, charts
Language:	eng

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