Beyond the solar surface: an observational study of solar coronal loops
type: CreativeWork
description: This thesis presents an observational analysis of structures in the solar corona. The plasmafl in the corona is low (<I), therefore, the emitting material is intimately linked to the magnetic fleldlines. The initial aim of this work, outlined in Chapter 3, is to take advantage of this relationship to calculate realistic magnetic reconnection rates from EUV observations. Then, Chapters 4-6 concentrate upon examining a colour-colour method to provide temperature profiles of coronal structures. Firstly, TRACE 171 A and 195 A data are used to indirectly determine a magnetic reconnection rate for a flare loop system on the limb of the Sun. The magnetic reconnection rate is calculated by measuring the footpoint velocity of the loop system and following the method adopted by Isobe et al. (2002). The footpoint velocity is thought to be equal to the rate at which successive loops brighten, in the emission lines, during the postflare phase. A typical footpoint velocity of 1.5 kms'±0.7 kmr' is obtained and a reconnection rate of -.0.00 1-0.03 is determined. Secondly, the double filter ratio temperature analysis method employed upon TRACE 171, 195 and 284 A coronal images is re-addressed. Two features from TRACE datasets published initially in Isobe et al. (2002) are reanalysed and a new TRACE example is also included for comparison. Only one of the original examples along with the new dataset are easily shown to be present in all three EUV passbands. This work investigates two important changes to the original analysis. A new temperature colour-colour curve is employed which utilises revised TRACE response functions; these take into account the emission from Fe VIII which significantly affects the 195 A passband. Also three different background subtraction techniques are used. Subsequently, the results show that when using this method for these examples, it is very difficult to assign specific temperature values to individual data points. Thirdly, an extensive investigation in…
abstract: This thesis presents an observational analysis of structures in the solar corona. The plasmafl in the corona is low (<I), therefore, the emitting material is intimately linked to the magnetic fleldlines. The initial aim of this work, outlined in Chapter 3, is to take advantage of this relationship to calculate realistic magnetic reconnection rates from EUV observations. Then, Chapters 4-6 concentrate upon examining a colour-colour method to provide temperature profiles of coronal structures. Firstly, TRACE 171 A and 195 A data are used to indirectly determine a magnetic reconnection rate for a flare loop system on the limb of the Sun. The magnetic reconnection rate is calculated by measuring the footpoint velocity of the loop system and following the method adopted by Isobe et al. (2002). The footpoint velocity is thought to be equal to the rate at which successive loops brighten, in the emission lines, during the postflare phase. A typical footpoint velocity of 1.5 kms'±0.7 kmr' is obtained and a reconnection rate of -.0.00 1-0.03 is determined. Secondly, the double filter ratio temperature analysis method employed upon TRACE 171, 195 and 284 A coronal images is re-addressed. Two features from TRACE datasets published initially in Isobe et al. (2002) are reanalysed and a new TRACE example is also included for comparison. Only one of the original examples along with the new dataset are easily shown to be present in all three EUV passbands. This work investigates two important changes to the original analysis. A new temperature colour-colour curve is employed which utilises revised TRACE response functions; these take into account the emission from Fe VIII which significantly affects the 195 A passband. Also three different background subtraction techniques are used. Subsequently, the results show that when using this method for these examples, it is very difficult to assign specific temperature values to individual data points. Thirdly, an extensive investigation in…
author: Noglik, Jane B.
language: en
keywords: F510 - Astrophysics
date published: 2007-01
date modified: 2026-07-24T01:36:06Z
provider: University of Central Lancashire
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Central Lancashire