Complex magnetic fields: an enigma of solar plasmas (Dundee-Durham consortium)

Lead Research Organisation: Durham University
Department Name: Mathematical Sciences

Abstract

The outer atmosphere of the Sun, the solar corona, is a dynamic plasma permeated by a magnetic field. This magnetic field is responsible for creating long-lived structures such as coronal loops, for heating the corona to its multi-million degree temperatures, and for explosive events such as solar flares and coronal mass ejections. These powerful explosions can greatly influence the Earth and its surrounding environment. They create the Northern and Southern lights, but also have the potential to damage satellites, power grids and pipelines, disrupt communications systems, and endanger astronauts. Understanding how these explosive processes take place requires a detailed understanding of the behaviour of the Sun's magnetic field, which is characterised by its complex three-dimensional structure. Gaining such an understanding is the aim of this work programme and is part of a wider goal in the scientific community of understanding the formation of structures in astrophysical plasmas.

Recent observational advances are providing us with a more and more detailed view of the Sun's magnetic field. But each increase in spatial resolution reveals finer scale magnetic structures, down to the resolution limit of even the most advanced telescopes. What is more, each increase in time cadence reveals more complex dynamics that shape the magnetic field and plasma on all scales. The over-arching theme of this consortium proposal is to explore the physical consequences of this magnetic complexity. We aim to understand how such complex magnetic fields are formed, how they evolve, and how they can build up and explosively release extreme amounts of energy. These questions are challenging, but must be addressed if we are to understand the full implications of what we are now observing.

We will address problems such as: What is the mechanism that makes the solar corona so hot? How do explosive events occur in the Sun's atmosphere? Can we develop new tools to help analyse these complex magnetic fields, and can we apply these tools to the evolution of the corona on global scales? What controls the lowest energy state to which the magnetic field of the corona can relax, and therefore how much energy is available to heat the plasma? How are particles accelerated in particular complex magnetic field structures?

We will use a combination of numerical simulations and mathematical modelling to tackle these questions, primarily using the non-linear partial differential equations of magnetohydrodynamics. The modelling will take input from the latest generation of solar telescopes, using various observations to verify and refine the theory. Combined, the results should help not only to explain and predict events in the solar corona and help answer STFC's Science Roadmap Challenge B:2 ("How does the Sun influence the environment of the Earth and the rest of the Solar System?") but also to understand some of the basic plasma physical processes that go on throughout the Universe.

Planned Impact

Eruptive magnetic storms on the Sun (Coronal Mass Ejections) regularly reach the Earth's space environment. The economic consequences of this space weather can be severe, and include damage to satellites and power grids, corrosion of oil and gas pipelines and disruption of communication systems. Furthermore, these events may endanger the health of astronauts and those onboard high-flying aircraft. The proposed research seeks to develop an understanding of how complex magnetic structures in the Sun's atmosphere change and interact, with these interactions being a critical part of the chain of events that generates solar eruptions. As such, a possible major impact of the proposed research will be on the international effort to develop reliable space-weather forecasting systems (given notice, defensive measures can the taken against the aforementioned effects).

Project 1.2, examining the consequences of complex magnetic fields in the global solar corona, will allow for significantly improved simulations of the Sun's magnetic field on global scales. A potential impact here will be on reconstructions of the Sun's magnetic field in the past which, in turn, will affect reconstructions of the Earth's climate in the past.

The proposed research should be seen in the wider framework of the analysis of complex multi-scale systems which we encounter in many areas of science: the weather, cellular networks, material sciences, neurosciences, nuclear sciences, etc. The theoretical tools and method created for investigating astrophysical plasmas have both benefited from and contributed to progress in these areas via exchanges of ideas, software and human resources.

More generally, astronomy has a strong cultural impact. Due to the Sun's close proximity and the stunning images being gathered by new satellites, solar physics has a great capacity to get young people interested in science, contributing to UK's skilled labour market. We will engage with schools and the general public on our research findings through the Schools Outreach Programme of the Division of Mathematics in Dundee, via press releases, articles in popular science magazines and public events such as the Dundee Science Festival. These methods are further documented in the Outreach section of the Pathways to Impact document.

Publications

10 25 50
publication icon
Chian A (2014) DETECTION OF COHERENT STRUCTURES IN PHOTOSPHERIC TURBULENT FLOWS in The Astrophysical Journal

publication icon
Gibb G (2016) Stellar coronal response to differential rotation and flux emergence in Monthly Notices of the Royal Astronomical Society

publication icon
Prior C (2014) ON THE HELICITY OF OPEN MAGNETIC FIELDS in The Astrophysical Journal

publication icon
Rachmeler L (2014) OBSERVATIONS OF A HYBRID DOUBLE-STREAMER/PSEUDOSTREAMER IN THE SOLAR CORONA in The Astrophysical Journal

publication icon
Russell A (2015) Evolution of field line helicity during magnetic reconnection in Physics of Plasmas

publication icon
Russell A (2015) Magnetic reconnection now and in the future in Astronomy & Geophysics

 
Description Progress has been made on all projects. Here is a summary of some of our key findings:
(1) We have shown that the field-line helicity is a robust and useful analytical tool for understanding the dynamics of plasmas with complex magnetic fields. In particular, we have demonstrated how it evolves during a turbulent plasma relaxation. Our analysis has unequivocally demonstrated the importance of higher topological invariants in constraining the evolution, and moreover has suggested how we could in future make predictions of the end state of such relaxation events. This work has implications for understanding heating in the Sun's atmosphere, but also more generally for understanding plasma relaxation events elsewhere in astrophysics or in laboratory plasmas (e.g. fusion machines).

(2) We have developed an improved "flux transport" model for the evolution of magnetic fields on the Sun's surface. The improvement is to account better for the structure of solar active regions, leading to better predictions of the overall magnetic field at the end of the solar cycle. This work has implications for understanding both short and long-term solar activity.

(3) We have studied the influence of our "non-potential" model for reconstructing the Sun's coronal magnetic field on predictions of the solar wind. Importantly, we have shown that there is a significant change compared to the standard "potential" model used in current space weather predictions. We are working with both the UK Met Office and US Air Force to further assess the possible benefits of our model for prediction.
Exploitation Route Our tools for analysing plasma relaxation can be applied to a wide variety of systems in astrophysics, laboratory plasma physics or even more widely in fluids.

Our work on improvements to space weather prediction has potential impact for predictions made by NOAA in the US and by the UK Met Office.
Sectors Aerospace, Defence and Marine,Environment

URL http://www.maths.dur.ac.uk/~bmjg46/
 
Description Basic Research Initiative
Amount $320,835 (USD)
Funding ID FA9550-14-1-0191 
Organisation Airforce Office of Scientific Research 
Sector Public
Country United States
Start 09/2014 
End 09/2017
 
Description Research Programme Grants
Amount £1,690,000 (GBP)
Organisation The Leverhulme Trust 
Sector Academic/University
Country United Kingdom
Start 09/2014 
End 09/2018
 
Description STFC Consortium Grant
Amount £34,823 (GBP)
Funding ID ST/N000781/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 04/2016 
End 03/2019
 
Description STFC Impact Acceleration Account
Amount £17,000 (GBP)
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 10/2015 
End 03/2016
 
Description STFC Impact Acceleration Account, Durham University
Amount £16,416 (GBP)
Organisation Science and Technologies Facilities Council (STFC) 
Sector Academic/University
Country United Kingdom
Start 09/2014 
End 03/2015
 
Description Summer Research Bursary for F. Bianchi
Amount £1,080 (GBP)
Organisation Royal Astronomical Society 
Sector Learned Society
Country United Kingdom
Start 07/2013 
End 09/2013
 
Title Bipolar magnetic region database 
Description Data set of bipolar magnetic regions determined from NSO synoptic carrington maps. 
Type Of Material Database/Collection of data 
Year Produced 2014 
Provided To Others? Yes  
Impact Has been used in several studies by myself and others. 
URL https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/Y5CXM8
 
Title sftdata code 
Description A 2d data-driven surface flux transport code in Matlab, as described in the paper Yeates et al, 2015, Solar Phys. 290, 3189. 
Type Of Material Computer model/algorithm 
Year Produced 2015 
Provided To Others? Yes  
Impact Has led to a joint publication with University of Oulu, in addition to my own projects. 
URL https://github.com/antyeates1983/sft_data
 
Description ISSI team on Global Non-Potential Magnetic Models of the Solar Corona 
Organisation International Space Science Institute (ISSI)
Country Switzerland 
Sector Academic/University 
PI Contribution I led the successful proposal to ISSI to run an International Team on this topic, and have led the team activities in two meetings at ISSI, Bern, Switzerland. I was first author of the final publication.
Collaborator Contribution Team members have attended the meetings and contributed research to the project.
Impact Two international team meetings, and a number of spin-off collaborations and publications. Final journal paper describing project now published in Space Science Reviews (Yeates et. al, "Global Non-Potential Magnetic Models of the Solar Corona During the March 2015 Eclipse"). Contributed model code to prediction of August 2017 solar eclipse by Predictive Science, Inc (http://www.predsci.com/corona/aug2017eclipse/).
Start Year 2015
 
Description MSSL Leverhulme Trust 
Organisation University College London
Department Mullard Space Science Laboratory
Country United Kingdom 
Sector Academic/University 
PI Contribution Contributed to Leverhulme Trust project "Probing the Sun: Inside and Out", PI Louise Harra (UCL/MSSL) by taking part in two research workshops (looking at modelling origin of Sun's polar field).
Collaborator Contribution Provided observations to compare with my modelling.
Impact Two talks at project workshops. Joint publication in Solar Physics (A.R. Yeates, D. Baker and L. van Driel-Gesztelyi, 2015).
Start Year 2013
 
Description Met Office 
Organisation Meteorological Office UK
Country United Kingdom 
Sector Public 
PI Contribution Developing numerical simulations of the solar wind for improved space weather forecasting.
Collaborator Contribution Assisting in development, running models, analysis, hosting meetings.
Impact Meetings, developing new numerical code (in progress). Has led to two joint publications so far: Edwards,Yeates, Bocquet & Mackay (2015) and Mackay, Yeates, Bocquet (2016).
Start Year 2013
 
Description NASA/LWS flux ropes 
Organisation National Aeronautics and Space Administration (NASA)
Country United States 
Sector Public 
PI Contribution I am consultant on a NASA/LWS targeted science team on Flux Ropes, led by Mark Linton (US Naval Research Laboratory). I have done modelling work, and attended two team meetings (in the US and in the UK).
Collaborator Contribution Collaborators have done modelling and observational work.
Impact Work is still underway.
Start Year 2015
 
Description Royal Observatory of Belgium 
Organisation Royal Observatory of Belgium
Country Belgium 
Sector Public 
PI Contribution Providing numerical simulation of the magnetic field in the solar corona.
Collaborator Contribution Providing observational data (PROBA2 satellite) for comparison, and training in using the data.
Impact Seminar talk. Multidisciplinary: involves applied mathematics and observational solar physics. We had a workshop on "coronal fans" at ESA in Madrid, in November 2016.
Start Year 2014
 
Description UCLA Basic Plasma Science Facility 
Organisation University of California, Los Angeles (UCLA)
Department Physics and Astronomy
Country United States 
Sector Academic/University 
PI Contribution Applied our analysis techniques to experimental magnetic field data from interacting flux ropes.
Collaborator Contribution Carried out the experiment.
Impact Multi-disciplinary involving laboratory plasma physics and solar physics/applied mathematics. Published paper on this work with C. Prior in Physical Review E (2018).
Start Year 2013
 
Description University of Oulu 
Organisation University of Ottawa
Department Department of Physics
Country Canada 
Sector Academic/University 
PI Contribution Provided flux transport model for historical magnetogram study. Performed further joint studies, took part jointly in ISSI team, and made two visits to Oulu.
Collaborator Contribution Provided historical data.
Impact We have a joint publication (Virtanen et al. 2017) and further publications in progress.
Start Year 2015
 
Description Colloquium talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Gave talk "Coronal dynamics and the Sun's magnetic memory" to general audience at Space Sciences Lab Colloquium, UC Berkeley, California (ca 30 attendees).

Useful discussions.
Year(s) Of Engagement Activity 2014
 
Description Colloquium talk (Madrid) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Gave colloquium talk at ICMAT, Madrid, which sparked questions and discussions.

Sharing of information with pure mathematics community on force-free magnetic fields.
Year(s) Of Engagement Activity 2014
 
Description Colloquium talk (NASA Goddard) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Gave talk to broad range of scientists at NASA Goddard Space Flight Centre, leading to discussion and questions.

Shared ideas.
Year(s) Of Engagement Activity 2014
 
Description ISSI International Team 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Led International Team at the International Space Science Institute on "Global non-potential magnetic models of the solar corona". Organising two meetings in Bern, Switzerland, and coordinating project to bring multiple research groups together (about 10 representatives). Led to new study and intercomparison of models. Published findings in Space Science Reviews article.
Year(s) Of Engagement Activity 2015,2016,2017
URL http://www.issibern.ch/teams/modelsolcorona/
 
Description Public lecture (Bishop Auckland Astronomical Society) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Gave talk about Sun to Bishop Auckland Astronomical Society alongside practical solar observing session. About 20 members present. The talk sparked significant questions and discussion.
Year(s) Of Engagement Activity 2015
URL http://baastro.nstars.org/
 
Description Public lecture (Durham Astronomical Society) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Gave talk on "Our Variable Magnetic Sun" to Durham Astronomical Society, attended by about 30 members. Talk sparked significant interest with many questions and considerable discussion.
Year(s) Of Engagement Activity 2016
URL http://www.durhamastronomy.org/
 
Description Public lecture (Newcastle Astronomical Society) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Gave talk on "Our Variable Magnetic Sun" to Newcastle Astronomical Society, about 25 members present. Sparked significant questions and discussion afterwards.
Year(s) Of Engagement Activity 2016
URL http://www.newcastleastro.co.uk/
 
Description Public lecture (Sunderland Astronomical Society) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Invited lecture about "Our Variable Magnetic Sun" to amateur astronomy society. Ca. 30 people attended, and the talk sparked significant questions and discussion.
Year(s) Of Engagement Activity 2015
URL http://www.sunderlandastro.com/
 
Description Public talk. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Regional
Primary Audience Undergraduate students
Results and Impact 15 people attended Cafe Scientifique talk, and associated questions and discussion.

Promoted UK solar physics to broad range of science students.
Year(s) Of Engagement Activity 2013
 
Description Pure mathematics seminar 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Local
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Gave guest talk to Geometry and Topology seminar (ca 30 attendees): "Magnetic Field Topology".

Promoted interesting discussions.
Year(s) Of Engagement Activity 2013
 
Description RAS Specialist Discussion Meeting 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Co-organised RAS specialist discussion meeting on "Magnetic Reconnection: Where now and where next?". About 50-60 participants from variety of backgrounds/subject areas. Sparked significant discussion and led to our being asked to write a review article for the Astronomy & Geophysics magazine.
Year(s) Of Engagement Activity 2014
 
Description Research presentation at ISSI meeting on Magnetic Helicity, Switzerland 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Gave invited presentation to working group on magnetic helicity at ISSI, Bern. Took part in discussions of group research project.
Year(s) Of Engagement Activity 2016
URL http://www.issibern.ch/teams/magnetichelicity/
 
Description Research talk (Lockheed Martin) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Gave research seminar on Surface flux transport and the limits of solar cycle prediction during visit to Lockheed Martin Space and Astrophysics Lab, Palo Alto, California. Approximately 10 people. Led to significant discussion and ongoing research collaboration.
Year(s) Of Engagement Activity 2015
 
Description Research talk (US Air Force) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Gave research talk on Surface flux transport and the limits of solar cycle prediction to the US Air Force Research Lab, Albuquerque, New Mexico. About 15 attendees - sparked questions and discussion.
Year(s) Of Engagement Activity 2015
 
Description SHINE workshop, New Mexico 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presented and discussed my research as part of SHINE workshop, USA. Audience included wide range of plasma physicists interested in heliosphere. At the same meeting, I co-chaired the session on magnetic maps.
Year(s) Of Engagement Activity 2016
 
Description Seminar (Royal Observatory of Belgium) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Gave research seminar to observational solar physicists.

Lead to new collaboration as well as discussion.
Year(s) Of Engagement Activity 2014
 
Description Seminar at Centre for Fusion, Space and Astrophysics, University of Warwick 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Seminar talk about my work to a broad audience of plasma physicists.
Year(s) Of Engagement Activity 2016
 
Description Seminar at Glasgow University 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Gave Applied Mathematics Seminar about my research at Glasgow University, to a broad audience of applied mathematicians.
Year(s) Of Engagement Activity 2016
 
Description Solar Eclipse (2015) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Assisted with display by Kielder Observatory during partial solar eclipse in 2015, Newcastle City Centre. My role was to answer questions from the public about the Sun and solar physics. Led to interest in solar physics among the public with over 100 people gathering.
Year(s) Of Engagement Activity 2016
 
Description Talk at Bz workshop, New Mexico 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Gave research presentation at Bz workshop organised by US Air Force.
Year(s) Of Engagement Activity 2016
 
Description Talk at IUTAM symposium on "Helicity structures and singularity in fluid and plasma dynamics" 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Gave talk about my research to general audience drawn from different areas of fluid dynamics.
Year(s) Of Engagement Activity 2016
 
Description Talk at RAS specialist discussion meeting, London 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Gave presentation about my research at RAS specialist discussion meeting on Flux Emergence.
Year(s) Of Engagement Activity 2016
URL http://www.maths.gla.ac.uk/~dmactaggart/ras.html
 
Description Talk at UKMHD meeting, Glasgow 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Talk about my research to national audience from all areas of MHD.
Year(s) Of Engagement Activity 2016
 
Description UKSP Nugget 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Wrote online UK Solar Physics nugget; for disseminating research to the public.
Year(s) Of Engagement Activity 2015
URL http://www.uksolphys.org/uksp-nugget/63-can-a-single-active-region-change-the-course-of-the-solar-cy...
 
Description UKSP Nugget 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Wrote online UK Solar Physics "nugget" for disseminating research to the public.

None yet (other than page views).
Year(s) Of Engagement Activity 2014
URL http://www.uksolphys.org/uksp-nugget/47-filaments-and-magnetic-memory-in-the-solar-corona/
 
Description Workshop on Magnetic Flux Ropes 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Talk entitled "Quantifying reconnection in magnetic flux ropes". 30 invited delegates from different fields of plasma physics attended multi-disciplinary Workshop on Magnetic Flux Ropes at UCLA, California.

Promoted ideas to specialists beyond solar physics, and started new collaboration with experimenters.
Year(s) Of Engagement Activity 2014