Electron Acceleration, Transport and Loss in Planetary Radiation Belts

Lead Research Organisation: NERC British Antarctic Survey
Department Name: Science Programmes

Abstract

How electrons are accelerated and lost inside planetary and astrophysical magnetic fields are major unresolved questions. At Earth there has been a major advance: that intense electromagnetic waves at frequencies of a few kiloHertz can accelerate electrons up to relativistic energies via cyclotron resonant wave-particle interactions. This result has transformed generally accepted ideas on the Earth's radiation belts that have lasted 40 years or more, and has spurred new satellite missions such as NASA's Van Allen Probes mission and the Japanese ERG mission to test this and related ideas.

Intense electromagnetic waves are also observed inside the magnetic fields of Jupiter and Saturn which suggests that the same resonant acceleration and loss processes that occur at Earth could be important for all planetary radiation belts. The goal of this proposal is to test the hypothesis that cyclotron resonant wave-particle interactions are major electron acceleration and loss processes at Earth, Jupiter and Saturn, and play a major role in the formation of radiation belts at these planets.

The results of our research will help determine whether electron cyclotron resonant acceleration and loss processes are universal processes that are more widely applicable to the Sun and other astrophysical objects. It will help set new research goals for future spacecraft missions to the planets, provide research training for young scientists, develop computer models for space weather that will be of direct use to the space insurance, satellite construction, and satellite service industries, and leave a legacy of understanding that will last long after the completion of the project.

Planned Impact

We have identified the following non-academic users who would benefit from the proposed research:

Space insurance
One of the products of our proposed research will be an improved radiation belt model for the Earth which will better reproduce variations in the energetic electron flux during geomagnetic storms. These energetic charged particles are known to damage spacecraft. We have already spoken to Atrium Insurance and the Willis Research Network who have stated that "the possibility of using the research models to allow insurers to confirm the past existence of damaging geomagnetic conditions when handling claims for satellite damage is something that is of interest to insurers".

Satellite construction companies
Satellite construction companies use models of the radiation environment to design spacecraft. These models enable them to provide shielding for sensitive electronic components, to protect them from energetic electrons and protons which can penetrate the spacecraft and cause damage. These standard models are based on limited data at different times of the solar cycle. The radiation belt model that will be improved in the proposed research will be able to better reconstruct the Earth's radiation belts for the whole solar cycle.

Satellite service providers
Satellite service companies (e.g., TV and internet providers) have an interest in the safe and reliable operation of their spacecraft. There are a number of occasions when satellites have malfunctioned during major geomagnetic storms, for example, during the October 2003 geomagnetic storm more than 47 spacecraft reported malfunctions and one was a total loss. The work proposed in Project 1 will enable better modelling and forecasting of the relativistic electron flux experienced by the entire satellite fleet, including satellites in low Earth orbit, medium Earth orbit and geosynchronous orbit. We have developed contacts with a number of important stakeholders in the space industry including Mr D Pitchford at SES (see letter of support) and will continue to work with key stakeholders during the course of the project.

Space Agencies
Space Agencies produce models of the radiation environment for the Earth and planets for mission planning. The NASA Juno mission is due to arrive at Jupiter in 2016 and the ESA JUICE mission scheduled for launch in 2022. Data on the radiation environment at Jupiter are very limited. Previous missions did not sample the regions proposed for the next generation of spacecraft. Our radiation belt models for Jupiter and Saturn will provide a means to calculate the electron radiation flux for orbits which have not been sampled. The PI of this proposal has already been asked to comment on radiation dose models for Jupiter by the ESA and we will continue to discuss our data and computer codes for future collaborations.

General public
Space research is widely held to be an area that attracts young people (11-16) into Science, Technology, Engineering and Mathematics. The huge success of the BBC's recent major "Stargazing Live" TV programmes which included hunting for the aurora borealis and live discussions on the Sun-Earth connection (on which the PI featured) is compelling evidence of the public's interest in space research. We anticipate significant public interest in our results at Earth and the planets and propose significant outreach activities to disseminate results.

Policy makers
Space weather is now on the UK National Risk Register and the Cabinet Office must provide contingency planning in case of an extreme event such as a space weather super-storm. The PI of this proposal is on the UK Space Environment Impacts Group which provides advice on space weather hazards to the Cabinet Office. The proposed research includes the Earth's radiation belts, which damage spacecraft, and will be of direct interest to policy makers.

Publications

10 25 50
 
Description We have found that a special type of plasma wave, called Z mode waves, play a major role in the formation of Saturn's radiation belts. The waves accelerate electrons to relativistic energies just outside the main ring system. This is a ground-breaking result that changes the long-held idea of how Saturn's electron radiation belts are formed. It also highlights the importance of Z mode waves that have largely been ignored. Z mode waves have also been found at Earth and Jupiter, but they have never been explored. This work opens up a new area of research to test their importance more generally at the magnetised planets.
We have also completed a survey of Z mode waves at Saturn and a new survey of chorus waves at Jupiter - both of which are responsible for electron acceleration.

We have now found (2018) that there is a huge increase in the power of plasma waves near the moons Europa and Ganymede at Jupiter. This has a major implication for the origin of the radiation belts at Jupiter.
Exploitation Route To help define the energy range for particle detectors on a new ESA spacecraft mission to Jupiter - JUICE, and NASA Europa mission.

Help define the scientific goals of new spacecraft missions such as Europa Clipper to Jupiter.
Sectors Aerospace, Defence and Marine

 
Description Presentations to various Astronomical societies including the Cambridge Astronomical Association (125 general public), Ely Astronomy Club, Stour Astronomy Society, Loughton Astronomy Club. Emma Woodfield also gave the Norah Boyce Science Lecture to the University of the 3rd Age in Cambridge and engaged with the public over 2 full days at the Excel Centre in London at an event called New Scientist Live - organised by New Scientist Magazine in Sept 2016. We have also engaged directly with artists of many different genres at the British Antarctic Survey's "Data into Art" workshop and been into a primary school to talk to year 1 students.
First Year Of Impact 2016
Sector Education,Leisure Activities, including Sports, Recreation and Tourism
Impact Types Cultural,Societal

 
Title BAS Radiation Belt Model 
Description The BAS radiation belt model is designed to simulate the variability of the Earth's radiation belt. It is a 3d model and is the equivalent to a global circulation model in atmopsheric physics - but applied to space. It is used as a basic research tool to understand the physical processes governing the acceleration, transport and loss of electrons in the radiation belts. It has also been applied to Jupiter and Saturn. There is a verion of the code that is used to predict the radiation belts for space weather applications. 
Type Of Material Computer model/algorithm 
Year Produced 2014 
Provided To Others? Yes  
Impact The model has been used to show how plasma waves play a major role in the formation of the Earth's radiation belts. 
URL https://www.bas.ac.uk/science/research-models/bas-radiation-belt-model-bas-rbm/
 
Title HOTRAY 
Description HOTRAY is a computer program that can trace the path of any type of wave through a hot magnetised plasma. It has been used successfully in the Earth's ionosphere, magnetosphere, Jupiter, Saturn, the solar wind and in lab plasmas, 
Type Of Material Computer model/algorithm 
Provided To Others? Yes  
Impact There are over 100 peer-reviewed research publications using HOTRAY, including collaborations with USA, Japan, and Europe. 
URL https://www.bas.ac.uk/science/research-models/hotray-ray-tracing-model/
 
Title PADIE code 
Description The PADIE code is designed to compute the pitch angle and energy diffusion co-efficients due to the interaction between plasma waves and high energy charged particles in space - in particualr the radiation belts of Earth, Jupiter and Saturn. 
Type Of Material Computer model/algorithm 
Provided To Others? No  
Impact It has been used in many peer reviewed research papers to show how different types of plasma waves can cause acceleration and loss of high energy electrons and protons in space. 
URL https://www.bas.ac.uk/science/research-models/padie-pitch-angle-diffusion-of-ions-and-electrons/
 
Title Rapid electron acceleration in low density regions of Saturn's radiation belt by whistler mode chorus waves 
Description Radiation belts are hazardous regions found around several of the planets in our Solar System. They consist of very hot, electrically charged particles that are trapped in the magnetic field of the planet. At Saturn the most important way to heat these particles has for many years been thought to involve the particles drifting closer towards the planet. This paper adds to the emerging idea at Saturn that a different way to heat the particles is also possible where the heating is done by waves, in a similar way to what we find at the Earth. This work is reported in the paper "Rapid electron acceleration in low density regions of Saturn's radiation belt by whistler mode chorus waves" by E.E. Woodfield et al., 2019. The data provided here enable reconstruction of all the figures in the paper. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
 
Description Dr J D Menietti 
Organisation University of Iowa
Country United States 
Sector Academic/University 
PI Contribution I lead the research project
Collaborator Contribution Analysis of data from the Galileo probae at Jupiter and Cassini spacecraft at Saturn
Impact see our research papers
 
Description Lancaster Planets 
Organisation Lancaster University
Department Department of Physics
Country United Kingdom 
Sector Academic/University 
PI Contribution Emma Woodfield has collaborated with the Space and Planetary Physics Group in the Department of Physics at Lancaster University by visiting Dr. S Badman and working with her and her PhD student resulting in a co-authorship on a recently published paper.
Collaborator Contribution The majority of the work on this research project was performed by Rebecca Gray and her supervisor, Dr. S Badman.
Impact Gray, RL, Badman, SV, Woodfield, EE, Tao, C, Characterization of Jupiter's secondary auroral oval and its response to hot plasma injections,JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, Volume: 122 Issue: 6 Pages: 6415-6429, DOI: 10.1002/2017JA024214, 2017
Start Year 2016
 
Description Yuri Shprits 
Organisation Massachusetts Institute of Technology
Country United States 
Sector Academic/University 
PI Contribution Scientific input to research papers.
Collaborator Contribution Scientific input to research papers.
Impact Shprits, Y. Y., J. D. Menietti, X. Gu, K. C. Kim, and R. B. Horne (2012), Gyro-resonant interactions between the radiation belt electrons and whistler mode chorus waves in the radiation environments of Earth, Jupiter, and Saturn, a comparative study, J. Geophys. Res., 117, A11216, doi: 10.1029/2012JA018031. Menietti, J. D., Y. Y. Shprits, R. B. Horne, E. Woodfield, G. B. Hospodarsky, and D. A. Gurnett (2012), Chorus, ECH, and Z-mode emissions observed at Jupiter 2 and Saturn and possible electron acceleration, J. Geophys. Res., 117, A12214, doi: 12210.11029/12012JA018187. Woodfield, E. E., R. B. Horne, S.A. Glauert, J. D. Menietti, and Y. Y. Shprits (2013), Electron acceleration at Jupiter: greater input from cyclotron-resonant interaction with whistler-mode chorus waves, Ann Geophys., 31, 1619-1630, doi:10.5194/angeo-31-1619-2013. not multi-disciplinary
Start Year 2011
 
Description "Data into Art" - Art workshop at BAS 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Other audiences
Results and Impact Approx 30 people attended a "Data into Art" workshop at the Aurora Innovation Centre at the British Antarctic Survey(BAS) to engage with scientists from BAS to inspire them in their chosen artform (from textiles to ice sculpture). Along with some of my colleagues I gave presentations on space weather and my work to multiple small groups of artists. All the artists were fascinated by the dance of particles and the sounds related to space weather that I showed them and there were many many questions about my science.
Year(s) Of Engagement Activity 2017
 
Description Cambridge Astronomical Association, 21st Oct 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 Approx 125 people attended a talk I gave to the Cambridge Astronomical Society, one of the biggest societies in the country, which sparked many questions and much discussion afterwards. I received requests for information from my talk so that the audience members could follow up on some of the things I talked about. I received a request to give a similar talk at another society as a result of this talk.
Year(s) Of Engagement Activity 2016
URL http://www.caa-cya.org/newversion/index.php
 
Description Cambridge University Astronomical Society, Nov 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Undergraduate students
Results and Impact I gave a public evening lecture to the Cambridge University Astronomical Society in November 2015 to an audience of about 30 people with a wide variety of interests and ages. There were lots of interesting and wide ranging questions at the end.
Year(s) Of Engagement Activity 2015
 
Description Ely Astronomy Club, 11th March 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 Approx 25 people attended a talk I gave to the Ely Astronomy Club, which sparked many questions and much discussion afterwards. I received requests for information from my talk so that the audience members could follow up on some of the things I talked about. The organisers were very pleased with how it went and hope to invite me back in 2 years time to do a different talk.
Year(s) Of Engagement Activity 2016
 
Description Europlanet Moons and Magnetospheres workshop 
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 I attended the European Union funded Europlanet workshop on "Moons and Magnetospheres" in Iceland in February 2019. This was a networking activity organised under the Europlanet EU grant.There were approximately 40 people in attendance for a week with participants from all over the world. I made many very valuable connections, particularly to the instrument teams for the ESA JUICE mission due to launch in 2022.

Attendance at this workshop resulted in a personal invitation to speak at the first meeting of the UK/Ireland Europlanet Hub in March 2020/
Year(s) Of Engagement Activity 2019
 
Description Loughton Astronomy Society, 13th Oct 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 Approx 30 people attended a talk I gave to the Loughton Astronomy Society, which sparked many questions and much discussion afterwards. I received requests for information from my talk so that the audience members could follow up on some of the things I talked about.
Year(s) Of Engagement Activity 2016
URL http://las-astro.org.uk/
 
Description New Scientist Live, Sept 2016 
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 did 2 full days on the British Antarctic Survey stand at the first New Scientist Live at the Excel Centre in London. This was a very large event with a very wide variety of people attending, myself and my colleagues spoke to many many visitors about all the work that BAS does including my work on planetary space weather. In particular I spoke to many children and their parents about my work as a scientist and the fascinating physics that goes on in space.
Year(s) Of Engagement Activity 2016
 
Description Norah Boyce Science Lecture, U3AC 12th April 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 invited to give one of the Norah Boyce Science Lectures for the University of the Third Age in Cambridge. This was to an audience of approx 40 people which sparked much discussion on and around the topic of my talk.
Year(s) Of Engagement Activity 2016
URL http://u3ac.org.uk/
 
Description Papworth Astronomy Club Talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Talk about planetary space weather and our work on the radiation belts at Jupiter and Saturn to a local Astronomy club. Approx 20 people attended and there was much discussion after my talk.
Year(s) Of Engagement Activity 2019
 
Description Saturn workshop Southampton 
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 I attended the invitation only workshop on Saturn at Southampton University with colleagues from the UK and the USA. There were approx 20 attendees and there were wide ranging discussions about Saturn's magnetosphere. In particular the discussions sparked ideas for future research between myself and one of the international visitors which we followed up at a later meeting.
Year(s) Of Engagement Activity 2017
 
Description School Visit (Monkfield Park, Yr 1) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact I went into Monkfield Park Primary School to talk to all the Year 1 pupils as part of their school's science week. My visit was a mixture of short presentations by me with interactive games using an inflatable solar system as a focus and some planetary themed tasks for the children. The theme I used was Planetary Exploration as part of the wider theme of the week of "exploring". The school science coordinator and school science govenor also observed for part of the session and were very happy with how engaged the children were, and I spoke to them more specifically about the work I do with Jupiter and Saturn. The children were very enthusiastic and came up with a wide variety of questions and the year 1 teachers were also very interested. Of particular use to them at this point in the curriculum was talking about distances involved and units etc.
Year(s) Of Engagement Activity 2018
 
Description School visit (Monkfield Science week 2019, Yr 3) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact I visited Monkfield Park Primary School as part of their science week in summer 2019. I did the same session on the "Sounds of Space" to two year 3 classes. The session involved activities for the children to join in with and a Powerpoint demonstration about the sounds of space. There were approximately 60 children overall, 2 teachers and 2 teaching assistants. The children really enjoyed themselves and actively got involved. I have been asked back again for science week in 2020.
Year(s) Of Engagement Activity 2019
 
Description Stour Astronomy Club (2nd visit) 
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 invited to speak again at Stour Astronomy Club following my previous successful visit 2 years ago. I gave a new talk on the spacecraft missions that my work uses. Approx 25 people attended and there were many enthusiastic questions after my talk.
Year(s) Of Engagement Activity 2019
 
Description Stour Astronomy society, 7th March 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Approx 25 people attended a public lecture I gave at Stour Astronomy Society. The talk generated much discussion and thanks from the organisers.
Year(s) Of Engagement Activity 2017
URL http://www.strellis.com/SAS/index.shtml