Nanoflares: Explosive Heating of our Sun's Atmosphere

Lead Research Organisation: Queen's University of Belfast
Department Name: Sch of Mathematics and Physics

Abstract

The Sun is one of the most important objects for humankind, with solar activity driving "space weather" and having a profound effect on the Earth's environment. We can directly see the effects of the Sun's powerful radiation through fascinating sights on Earth, such as the aurora borealis. However, it is the paradoxical nature of our Sun's temperature structure that continues to frustrate scientists. One of the greatest scientific problems plaguing physicists is the fact that the outer atmosphere of our Sun is much hotter than its surface. Common sense leads us to believe that the local temperature will decrease as we move away from the Sun's 6000 K surface temperature. However, the corona, an atmospheric layer a few thousand km above the surface, radiates with a temperature exceeding one million degrees. Efforts to understand the heating processes responsible have remained at the forefront of observational and theoretical research for over 50 years, producing a popular class of theory known as flare heating. This mechanism suggests that turbulent plasma processes cause the magnetic field lines embedded in the Sun's atmosphere to become twisted and stretched. The process of magnetic reconnection results in these strained field lines returning to a more stable configuration, but releasing huge quantities of energy in the process. A large-scale solar flare can release in excess of 10^25 Joules of energy during a single event; the equivalent of over 5 million times more than the total combined energy of all atomic bombs ever detonated. However, these large events are too rare to support the continuously elevated temperatures in our Sun's outer atmosphere. Instead, it is believed that small-scale flares, or "nanoflares" with an equivalent energy of a single modern atomic bomb, may occur with such regularity that they can provide a continuous basal background heating.

It is my desire to help improve our understanding of the physical processes at work within the Sun's atmosphere, an object that is so influential to life on Earth. A natural consequence of understanding the effects of solar flares will be the ability to predict solar activity, something that will ultimately allow us to protect ourselves from fierce outbursts of space weather. To pursue this crucial agenda, we need to observe and model these explosive processes occurring in the Sun's atmosphere on their intrinsic scales. A new breed of highly sensitive scientific cameras will allow for the first time fundamental processes associated with the release of magnetic energy to be studied at an unprecedented level of detail. With an STFC Research Grant, a post-doctoral researcher will employ one of these modern pieces of equipment to image a variety of magnetic structures in the Sun's atmosphere with frame rates approaching 100 per second. The intensities of all structures will be monitored, with the characteristics of small-scale nanoflares evaluated. An in-depth examination of the regions where nanoflare activity is omnipresent will allow the processes at work to be compared precisely to the underlying magnetic field configurations. Fundamental parameters deduced from high-resolution observations will be incorporated into advanced computer simulations. Large computer clusters, often exceeding 200 CPUs, will be used to examine the effects of sub-resolution nanoflare activity on the intensity profiles extracted from the high-resolution observations. A direct comparison between the simulations and the observations will be undertaken, with key nanoflare characteristics determined, including the reconnection rates, the total energy released, and the plasma relaxation time scales. For the first time, the conditions promoting nanoflares will be understood, with the specific role they play in the heating of our Sun's atmosphere evaluated.

Planned Impact

The proposed programme of research will have significant impact worldwide, including important aspects within the scientific community, beneficiaries within the commercial sector, and assisting with the public understanding of science. A brief overview of how this research will contribute is outlined below.

Commercial Sector:
Current instrumentation on ground-based telescopes, including the STFC-supported Rapid Oscillations in the Solar Atmosphere (ROSA; Jess et al. 2010, Sol. Phys., 261, 363) camera system, typically employ 1 megapixel CCD cameras for scientific imaging at frame rates of 30 per second. Recently, the UK has benefitted from a major industrial drive to provide high sensitivity, fast readout, and scientifically calibrated imaging solutions for the upcoming Advanced Technology Solar Telescope and the European Solar Telescope, which are due to see first light in 2018 and 2025, respectively. The next-generation sCMOS detectors house much larger 5.5 megapixel chips, and when combined with superior read noise characteristics and high quantum efficiencies, will not only result in a major increase in the size of the captured field-of-view (550% increase), but also in higher frame rates (up to 100 per second) to allow dynamic phenomena to be captured with unprecedented accuracy. The proposed programme of research will pioneer the use of these cutting-edge cameras which have been designed for research projects that require large format detectors operating at high frame rates, hence producing very large data rates. For example, a new sCMOS camera will generate approximately 30 TB of data during a typical observing run of 8 hours. ANDOR Technology, a world leader in scientific imaging and spectroscopy, has identified large format high-speed sCMOS detectors as a growing market, especially with the next generation of astronomical telescopes requiring such detectors. Over the next number of years, I plan to provide expertise to ANDOR to assist their international competitiveness by creating:

1. Custom design solutions for large area, low noise cameras operating at high frame rates. Key to this will be the fundamental requirement to maintain respectable levels of sensor cooling (thus eliminating noise associated with dark current), a particular challenge for large area detectors.

2. Investigations into the design of mosaic platforms.

3. Answers to the issue of multi-port readout functionality - i.e. how to handle the data generated simultaneously by numerous high-speed detectors.

Public Understanding of Science:
The Sun has recently attracted a wealth of media attention due to its heightened activity in the form of flares, coronal mass ejections, and associated aurora in the Earth's upper atmosphere. This media fascination is likely to continue for a number of years until the Sun passes through a maximum in its solar cycle. There is always a high demand for information that the general public can readily grasp and understand. Due to the close proximity of the Sun to the Earth, and its profound impact on life, I feel the expected major outcomes of the proposed programme of research will be suitable for widespread media involvement. To date, I have extensively publicised my research activities through both professional and public outreach activities, including invited seminars at amateur astronomy meetings, and participation in high-school open days. In order to promote public understanding of this work, and indeed stir the imagination of all in the field of science, it is imperative to continue public outreach activities. My work has received widespread media attention in recent years through reports, press releases and radio interviews in conjunction with the British Broadcasting Corporation (BBC), NASA, local and national newspapers, and high-impact international magazines including National Geographic. I envisage this project will maintain a high level of media linkage over the next number of years.
 
Title Nature Physics cover art 
Description An image from the HARDcam instrument (funded by STFC grant ST/L002744/1) was selected for the cover of the February 2016 edition of Nature Physics. 
Type Of Art Image 
Year Produced 2016 
Impact Considerable interest has been created in the USA where the STFC-funded instrument is now based, with many new research groups wishing to collaborate and use scientific images captured from HARDcam. 
URL http://www.nature.com/nphys/journal/v12/n2/covers/index.html
 
Description This work is focused on the examination of small-scale eruptive events taking place in our Sun's atmosphere. Research has revealed that minute explosions, or 'nanoflares', are occurring within our Sun's tenuous layers every few seconds. We also seem to see changes in their energetics and activity levels depending on the background magnetic field present within that layer of the Sun's atmosphere. This project also attempted to replicate such results through in-depth modelling to better reveal the mechanisms that drive these small-scale explosions, and a publication giving details of such modelling was published in The Astrophysical Journal in January 2019.
Exploitation Route Our statistical approaches and modelling codes (with test cases) were published in a front-ranking astrophysical journal, with the goal of making the programme codes publicly available shortly after publication to all international researchers.
Sectors Aerospace, Defence and Marine,Creative Economy,Education,Energy,Environment,Financial Services, and Management Consultancy,Other

 
Description The research undertaken in this grant has resulted in numerous public outreach and social events which have helped to raise the awareness of science to the general public. We have participated in numerous high-impact national events such as Stargazing Live and Jupiter Watch which attracted thousands of the general public.
First Year Of Impact 2014
Sector Aerospace, Defence and Marine,Communities and Social Services/Policy,Creative Economy,Digital/Communication/Information Technologies (including Software),Education,Energy,Environment,Financial Services, and Management Consultancy,Other
Impact Types Cultural,Societal,Policy & public services

 
Description Invited reviewer for the Polish National Science Centre
Geographic Reach Europe 
Policy Influence Type Participation in a advisory committee
Impact Panel provides funds for the hiring of staff and students.
 
Description Industry-linked award
Amount £2,398,846 (GBP)
Funding ID 059RDEN-1 
Organisation Randox Laboratories 
Sector Private
Country Global
Start 05/2017 
End 09/2021
 
Description STFC Projects Peer Review Panel - large projects
Amount £1,902,471 (GBP)
Funding ID ST/L006308/1 
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 06/2014 
End 05/2018
 
Title Monte Carlo nanoflare statistics 
Description We have finalised a statistical approach that is able to link observations to the quantitative presence of nanoflares through Monte Carlo techniques. This code is now publicly available to all researchers following publication. 
Type Of Material Improvements to research infrastructure 
Year Produced 2017 
Provided To Others? Yes  
Impact New collaborative partnerships. 
URL https://iopscience.iop.org/article/10.3847/1538-4357/aaf8ae/meta
 
Title Using magneto-hydrodynamic waves to map the coronal magnetic field 
Description These methods are a novel new technique to use the omnipresent nature of propagating magneto-acoustic waves in the Sun's corona to map the magnetic field strength several thousand kilometres above the solar surface. 
Type Of Material Improvements to research infrastructure 
Year Produced 2016 
Provided To Others? Yes  
Impact Significant interest in our methods and programs, with additional publications currently under development. 
URL http://www.nature.com/nphys/journal/v12/n2/full/nphys3544.html
 
Description Collaborative Research 
Organisation California State University, Northridge
Department Department of Physics and Astronomy
Country United States 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation Catholic University of Louvain
Department Centre for Mathematical Plasma-Astrophysics
Country Belgium 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation Institute of Astrophysics of the Canary Islands
Country Spain 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation Lockheed Martin
Department Advanced Technology Center
Country United States 
Sector Private 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation National Astronomical Observatory of Japan
Country Japan 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation National Institute for Astrophysics
Department Arcetri Observatory
Country Italy 
Sector Public 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation National Solar Observatory (NSO)
Country United States 
Sector Public 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation Northumbria University
Department Mathematics and Information Sciences
Country United Kingdom 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation University of Calabria
Department Department of Physics
Country Italy 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation University of Manchester
Department Jodrell Bank Centre for Astrophysics
Country United Kingdom 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation University of Oslo
Country Norway 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation University of Sheffield
Department Automatic Control and Systems Engineering
Country United Kingdom 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation University of Sheffield
Department Solar Physics and Space Plasma Research Centre
Country United Kingdom 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Collaborative Research 
Organisation University of St Andrews
Department School of Mathematics and Statistics
Country United Kingdom 
Sector Academic/University 
PI Contribution We acquired, analysed and interpreted data with the help of the above collaborations.
Collaborator Contribution Collaborative partnership for research and subsequent publications.
Impact Multiple publications in refereed scientific journals.
Start Year 2009
 
Description Article published in Cosmos Magazine (2015) 
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 I published a research-focused article in the international Cosmos Magazine, which attracts ~110,000 readers each month.
Year(s) Of Engagement Activity 2015
URL https://cosmosmagazine.com/technology/early-warning-system-solar-flares
 
Description Article published in The Conversation magazine 
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 I published an invited article in The Conversation magazine related to space weather, receiving ~90,000 reads.
Year(s) Of Engagement Activity 2015
URL https://theconversation.com/new-early-warning-system-could-protect-earth-from-explosive-space-weathe...
 
Description DNA of Innovation: Volume V 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact I represented the School of Mathematics and Physics at the DNA of Innovation: Volume V public showcase event.
Year(s) Of Engagement Activity 2015
 
Description NI Science Festival 2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact I was asked to give one of the opening lectures for the 2016 NI Science Festival, which sparked many questions from school-age pupils. I have since emailed them more information, hopefully fuelling their interest in STEM subjects.
Year(s) Of Engagement Activity 2016
URL http://www.nisciencefestival.com/event.php?e=239
 
Description Press movie for the DNA of Innovation: Volume V showcase event (2015) 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact This was a press movie produced by QUB to draw media attention to The DNA of Innovation: Volume V showcase event.
Year(s) Of Engagement Activity 2015
URL http://star.pst.qub.ac.uk/~dbj/Press_Media/QUB_DNA_interview.mp4
 
Description Public talk to sixth-form students (Belfast 2016) 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact 50 sixth-form pupils attended QUB to hear talks about career prospects in STEM subjects. My talk was received well and many pupils asked questions and requested followup material.
Year(s) Of Engagement Activity 2016,2017
 
Description Television interview for NVTV's Focal Point show 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact I was interviewed about science in Northern Ireland by NVTV's Focal Point TV programme.
Year(s) Of Engagement Activity 2015
URL http://star.pst.qub.ac.uk/~dbj/Press_Media/NVTV_Focal_Point_18November2015.mp4