Local Coronal Dynamics

Lead Research Organisation: University of St Andrews
Department Name: Mathematics and Statistics

Abstract

The Solar and Magnetospheric Theory Group (SMTG) of the University of St Andrews will work on the fundamental physical processes occurring in the Sun's atmosphere and planetary magnetospheres. For example: Why is the Sun's outer atmosphere (the corona) over 100 times hotter than the visible surface of the Sun so that the gas is ionized and forms a plasma?
The answer to such a key question depends upon a range of expertise and the SMTG is in an excellent position to answer these questions.
We study a wide variety of physical phenomena using mathematical modelling (a combination of fundamental theory, analytical models, computer simulations, forward modelling and observations). It is an integrated approach that is needed, i.e. a mixture of modelling methods and a comparison between observations from several satellite missions and the theoretical models. The topics we will investigate, using plasma theory, are: the physical mechanisms responsible for keeping the corona much hotter than the lower parts of the solar atmosphere (coronal heating). These mechanisms obey physical laws that can be expressed as nonlinear partial differential equations. However, what makes them distinct is that different phenomena require different dominant terms. Hence, the physical processes and the plasma response will be different in each case. It is the rich complexity of the non-linear equations that makes them hard to solve and to determine what the key physical processes are responsible for each heating event. A most important research tool is the parallel computer formed by linking many commodity processors together. Then the simulation involves splitting the problem up into smaller parts that run on different processors at the same time (in parallel). Thus, our simulations are completed quicker. Hence, with a job that would require 10 years on single machine, will be completed in a couple of weeks on 512 processors. We address key issues in the STFC Science Roadmap, especially, how does the Sun affect the Earth? However, a detailed understanding of the physics of our research topics are important not only for the Sun, solar-like stars and space weather, but also for understanding such diverse astrophysical processes such as star formation in giant molecular clouds, the evolution of astrophysical discs around stars, black holes and in Active Galactic Nuclei, and the physics of winds and outflows from stellar to extragalactic scales.

Planned Impact

While the main impact of the proposed research will undoubtedly be of academic in nature, there will also be significant economic and societal impact. The skills required for research in theoretical solar physics means that our group is continually producing people skilled in mathematical modelling, computational (including parallel computing) methods, visualisation techniques and logical thinking for non-academic professions. While nearly 40 former group members have gone on to academic positions, over 50 former group members have flourishing careers outside academia. Thus, we are enhancing the research capacity, knowledge and skills of businesses and organisations. Several former PhD students have joined the Atomic Weapons Establishment (Aldermaston) and GCHQ, potentially improving national security.

Our public lectures and presentations at various science fairs, for example during the International Heliospheric Year, have helped to increase public awarness in the importance of our research. Our visits to both primary and secondary schools have helped to enthuse students to study science, in general, and physics and mathematics, in particular. The Space Camp and Sutton Trust summer schools are particularly popular with primary and secondary pupils. The Sun-Trek and History of Mathematics websites are fantastic online resources that appeal to both children and the wider public.

On the academic impact front, we have organised many conferences over the years and, most recently, the major meetings of Hinode 6 in August 2012 and NAM 2013. We would like to organise an HPC workshop for new UK MHD PhD students who will be using the UKMHD Consortium facilities for their research.

Publications

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Bareford M (2013) Coronal heating by the partial relaxation of twisted loops in Astronomy & Astrophysics

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Bareford M (2015) Energy Release in Driven Twisted Coronal Loops in Solar Physics

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Bareford MR (2015) Shock heating in numerical simulations of kink-unstable coronal loops. in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences

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De Moortel I (2016) Transverse, propagating velocity perturbations in solar coronal loops in Plasma Physics and Controlled Fusion

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De Moortel I (2015) Recent advances in coronal heating. in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences

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Parnell CE (2015) Is magnetic topology important for heating the solar atmosphere? in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences

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Pascoe D (2014) STANDING KINK MODES IN THREE-DIMENSIONAL CORONAL LOOPS in The Astrophysical Journal

 
Description We have investigated how a magnetic field can heat the plasma inside solar coronal loops to above 1 million degrees, over 100 hotter than the underlying photosphere.
Exploitation Route This research will form the basis for future nvestigations in heating the corona by magnetic energy stored in stressed magnetic fields.
Sectors Education,Other

 
Description This award is for research on the local dynamics of magnetic fields in the solar corona. As well as contributing to our understanding of the role of magnetic fields heating the solar corona, it has also led to the development of numerical algorithms for following the evolution of the coronal plasma over long periods of time.
First Year Of Impact 2014
Sector Education,Other
 
Title Data underpinning: An MHD avalanche in a multi-threaded coronal loop 
Description  
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes