Thomas Williams

Thomas Williams
Aberystwyth University | AU · Department of Mathematics and Physics

PhD, MPhys (1:1)

About

16
Publications
809
Reads
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48
Citations
Additional affiliations
September 2014 - December 2016
Aberystwyth University
Position
  • Demonstrator
Description
  • Workshop demonstrator for 2nd year module mathematical physics, 3rd year module numerical methods, and 4th year module advanced numerical methods.
Education
September 2013 - May 2017
Aberystwyth University
Field of study
  • Solar Physics
September 2009 - July 2013
Aberystwyth University
Field of study
  • Physics with Planetary and Space Physics

Publications

Publications (16)
Article
Full-text available
The interaction of siphon flow with an initially linear Alfvén wave within an isolated chromospheric loop is investigated. The loop is modeled using 1.5D magnetohydrodynamics (MHD). The siphon flow undergoes a hydrodynamic (HD) shock, which allows the Alfvén instability to amplify the propagating waves as they interact with the shock and loop footp...
Article
Full-text available
Following the success of the first mission, the High-Resolution Coronal Imager (Hi-C) was launched for a third time (Hi-C 2.1) on 29 th May 2018 from the White Sands Missile Range, NM, USA. On this occasion, 329 seconds of 17.2 nm data of target active region AR 12712 was captured with a cadence of ≈ 4 s, and a plate scale of 0.129"/pixel. Using da...
Article
Full-text available
Previous work utilizing NASA's High-resolution Coronal Imager (Hi-C 2.1) 172 Å observations revealed that, even at the increased spatial scales available in the dataset, there may be evidence for coronal structures that are still not fully resolved. In this follow-up study, cross-section slices of coronal strands are taken across the Hi-C 2.1 field...
Article
Full-text available
Coronal loops form the basic building blocks of the magnetically closed solar corona yet much is still to be determined concerning their possible fine-scale structuring and the rate of heat deposition within them. Using an improved multi-stranded loop model to better approximate the numerically challenging transition region, this article examines s...
Preprint
Full-text available
Information on the rotation rate of the corona, and its variation over latitude and solar cycle, is valuable for making global connections between the corona and the Sun, for global estimates of reconnection rates, and as a basic parameter for solar wind modelling. Here, we use a time series of tomographical maps gained from coronagraph observation...
Article
Full-text available
Information on the rotation rate of the corona, and its variation over latitude and solar cycle, is valuable for making global connections between the corona and the Sun, for global estimates of reconnection rates and as a basic parameter for solar-wind modeling. Here, we use a time series of tomographical maps gained from coronagraph observations...
Preprint
Full-text available
Coronal loop observations have existed for many decades yet the precise shape of these fundamental coronal structures is still widely debated since the discovery that they appear to undergo negligible expansion between their footpoints and apex. In this work a selection of eight EUV loops and their twenty-two sub-element strands are studied from th...
Preprint
Full-text available
Coronal loops form the basic building blocks of the magnetically closed solar corona yet much is still to be determined concerning their possible fine-scale structuring and the rate of heat deposition within them. Using an improved multi-stranded loop model to better approximate the numerically challenging transition region, this paper examines syn...
Preprint
Full-text available
Previous work utilising NASA's High-resolution Coronal Imager (Hi-C 2.1) 172Å observations revealed that, even at the increased spatial scales available in the data-set, there may be evidence for coronal structures that are still not fully resolved. In this follow-up study, cross-section slices of coronal strands are taken across the Hi-C 2.1 field...
Article
Full-text available
Following the success of the first mission, the High-Resolution Coronal Imager (Hi-C) was launched for a third time (Hi-C 2.1) on 2018 May 29 from the White Sands Missile Range, NM, USA. On this occasion, 329 s of 17.2 nm data of target active region AR 12712 were captured with a cadence of ≈4 s, and a plate scale of 0 129 pixel −1. Using data capt...
Preprint
Full-text available
Following the success of the first mission, the High-Resolution Coronal Imager (Hi-C) was launched for a third time (Hi-C 2.1) on 29th May 2018 from the White Sands Missile Range, NM, USA. On this occasion, 329 seconds of 17.2 nm data of target active region AR 12712 was captured with a cadence of ~4s, and a plate scale of 0.129''/pixel. Using data...
Thesis
Full-text available
In this thesis the overarching investigation is the interaction of Alfven waves with flowing plasmas. The main consequence of this interaction is that Alfven waves are amplified in proximity of negative flow gradients. This amplification is investigated using three numerical models. The first and third studies implement fully non-linear Magnetohydr...
Article
Full-text available
The interaction of an intergranular downdraft with an embedded vertical magnetic field is examined. It is demonstrated that the downdraft may couple to small magnetic twists leading to an instability. The descending plasma exponentially amplifies the magnetic twists when it decelerates with depth due to increasing density. Most efficient amplificat...
Article
Full-text available
The interaction between a small twist and a horizontal chromospheric shocktube is investigated. The magnetic flux tube is modeled using 1.5-D magnetohydrodynamics. The presence of a supersonic yet sub-Alfvénic flow along the flux tube allows the Alfvénic pulse driven at the photospheric boundary to become trapped and amplified between the stationar...

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