Research@StAndrews
 
The University of St Andrews

Research@StAndrews:FullText >
Mathematics & Statistics (School of) >
Applied Mathematics >
Applied Mathematics Theses >

Please use this identifier to cite or link to this item: http://hdl.handle.net/10023/2081
This item has been viewed 34 times in the last year. View Statistics

Files in This Item:

File Description SizeFormat
RuthBownessPhDThesis.pdf10.89 MBAdobe PDFView/Open
Title: Current sheets in the solar corona : formation, fragmentation and heating
Authors: Bowness, Ruth
Supervisors: Hood, Alan W.
Keywords: MHD
Current sheets
Tearing mode instability
Magnetic reconnection
Issue Date: 30-Nov-2011
Abstract: In this thesis we investigate current sheets in the solar corona. The well known 1D model for the tearing mode instability is presented, before progressing to 2D where we introduce a non-uniform resistivity. The effect this has on growth rates is investigated and we find that the inclusion of the non-uniform term in η cause a decrease in the growth rate of the dominant mode. Analytical approximations and numerical simulations are then used to model current sheet formation by considering two distinct experiments. First, a magnetic field is sheared in two directions, perpendicular to each other. A twisted current layer is formed and we find that as we increase grid resolution, the maximum current increases, the width of the current layer decreases and the total current in the layer is approximately constant. This, together with the residual Lorentz force calculated, suggests that a current sheet is trying to form. The current layer then starts to fragment. By considering the parallel electric field and calculating the perpendicular vorticity, we find evidence of reconnection. The resulting temperatures easily reach the required coronal values. The second set of simulations carried out model an initially straight magnetic field which is stressed by elliptical boundary motions. A highly twisted current layer is formed and analysis of the energetics, current structures, magnetic field and the resulting temperatures is carried out. Results are similar in nature to that of the shearing experiment.
URI: http://hdl.handle.net/10023/2081
Type: Thesis
Publisher: University of St Andrews
Appears in Collections:Applied Mathematics Theses



This item is protected by original copyright

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

 

DSpace Software Copyright © 2002-2012  Duraspace - Feedback
For help contact: Digital-Repository@st-andrews.ac.uk | Copyright for this page belongs to St Andrews University Library | Terms and Conditions (Cookies)