Modelling the acceleration, transport and loss of radiation belt electrons to protect satellites from space weather (Rad-Sat)

Lead Research Organisation: University of Reading
Department Name: Meteorology

Abstract

Over the last 10 years the number of operational satellites in orbit has grown from 450 to more than 1300. We rely on these satellites more than ever before for a wide range of applications such as mobile phones, TV signals, internet, navigation and financial services. All these satellites must be designed to withstand the harsh radiation environment in space for a design life that can be as long as 15 years or more. Space weather events can increase electron radiation levels by five orders of magnitude in the Earth's Van Allen radiation belts causing satellite charging, disruption to satellite operations and sometimes satellite loss. For example, in 2003 it was estimated that at least 10% of all operational satellites suffered anomalies (malfunctions [1]) during a large space weather event known as the Halloween storm. It is therefore important to understand how and why radiation levels vary so much so that engineers and business can assess impact and develop mitigation measures. New results from the NASA Van Allen Probes and THEMIS satellite missions show that wave-particle interactions play the major role in the acceleration, transport and loss of high energy electrons and hence the variability of the radiation belts. This proposal brings together scientists from across the UK with stakeholders from the insurance and satellite services sector. We will process data from scientific satellites such as Van Allen Probes and THEMIS to obtain information on four very important type of waves known as magnetosonic waves, and radio-waves known as plasmaspheric hiss, lightning generated whistlers and transmitter waves. We will use data, theory and models to determine the properties of the waves and how they vary during space weather events. We will conduct studies to assess the acceleration, transport and loss of electrons due to each wave type using quasi-linear theory. We will use simulations to test whether nonlinear effects result in more particle acceleration and loss compared to quasi-linear theory. We will analyse compressional magnetosonic waves in the ultra-low frequency range and determine their effectiveness for transporting electrons across the magnetic field, and whether the transport is diffusive or not. We will incorporate the results of these studies into our state-of-the-art global radiation belt model to simulate known space weather events, and compare the results against data to highlight the importance of the waves and improve the model. We will also include local time effects and compare loss rates against data from the ground and other satellites to constrain the model. We will simulate extreme space weather events using our existing radiation belt model, and an MHD model so that we can assess the role of waves in the rapid formation of a radiation belt such as occurred in 1991 in less than 2 minutes. We will develop a stakeholder community consisting of space insurance, satellite operators and forecasters who will provide input to our research and who will use the results for risk assessment, anomaly resolution and operational planning. The project will deliver new processed data, a better forecasting capability and expertise that will support the UK Government assessment of severe space weather for the National Risk Register [2] and the growth of the satellite industry.

1. Cannon, P, S., et al. (2013), Extreme Space Weather: Impacts on Engineered Systems and Infrastructure, Royal Academy of Engineering, London, SW1A 2WH.
2. Cabinet Office, (2012), National risk register of civil emergencies, Whitehall, London SW1A 2WH, www.cabinetoffice.gov.uk.

Planned Impact

We have identified the following non-academic users who will benefit from our research:

Space insurance

One of the outputs of our research will be a set of radiation belt models which can be used to re-create the space radiation environment for severe space weather events that damage spacecraft. In their letter of support the Atrium Space Insurance Consortium have listed 4 ways in which they will benefit, including "further information to ensure the Lloyds Realistic Disaster Scenarios are accurate and that sufficient reserves are being made to cover the potential worst case insurance losses". Space insurance may also benefit from an independent assessment of the radiation environment for anomaly resolution.

Satellite construction companies

Satellite designers must protect satellites from the harsh radiation environment in space. They use models of the radiation environment to design for the 'reasonable worst case' but there is a very large uncertainty. Our research will simulate three different types of realistic worst case events, and will provide the radiation environment for medium Earth orbit for any part of the solar cycle. Satellite designers will be able to use our results to assess the amount of shielding needed to protect satellites, particularly for electric orbit raising and medium Earth orbit where there is relatively little radiation data.

Satellite operators

Satellite operators have an interest in the safe and reliable operation of their spacecraft. Space weather events can cause satellite anomalies (malfunctions) resulting in loss of service and in some cases total satellite loss. It can also mean a delay in reaching orbit and lost revenue if an anomaly affects electric orbit raising. Our research will lead to a step-change in space weather forecasting which will provide satellite operators with space weather situation awareness. This will enable them to plan mitigating action, for example, to suspend orbit manoeuvres and software updates, to ensure more staff are available to deal with problems, to have back-up systems immediately available, and when appropriate to inform users that some services may be at risk. Satellite operators will also benefit by using the results of our case studies of particular events to help identify the cause of a satellite anomaly.

Space Weather forecasting

The UK Met Office and the European Space Agency (ESA) are developing a system of forecasting all types of space weather. Our research will include new processes into our state-of-the-art forecasting models which will enable a step-change in our forecasting capability. Subject to further agreement, the Met Office and the ESA will benefit by turning our prototype forecasting system into a fully operational system for the satellite services sector.

General public

It is widely acknowledged that space research attracts young people into Science, Technology, Engineering and Mathematics (STEM subjects). The press coverage of the UK Astronaut Tim Peak and the International Space Station, is compelling evidence of the public's interest in space research. Our dissemination activities to schools and the public will help attract young people into the STEM subjects.

Policy makers

Extreme space weather was put on the UK National Risk Register in 2012 and revised in 2014. The UK Department of Energy and Industrial Strategy (DEIS) 'owns' the risk and is developing contingency plans to mitigate the impact of severe space weather. The Department will benefit from our research which will help define scenarios for severe space weather events, and how long they may last, and will provide the radiation environment needed for further impact assessment by engineers and business. The PI (Richard Horne) is a member of the Space Environment Impacts Expert Group (SEIEG) and will be able to provide advice to Government through this Group at meetings with DEIS.

Publications

10 25 50

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Allanson O (2018) On the inverse problem for Channell collisionless plasma equilibria in IMA Journal of Applied Mathematics

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Allanson O (2021) Electron Diffusion and Advection During Nonlinear Interactions With Whistler-Mode Waves in Journal of Geophysical Research: Space Physics

Related Projects

Project Reference Relationship Related To Start End Award Value
NE/P017274/1 30/04/2017 30/08/2020 £395,221
NE/P017274/2 Transfer NE/P017274/1 31/08/2020 29/04/2021 £86,450
 
Description Near-Earth space contains high-energy electrons that pose a threat to satellite technology. We understand that when these electrons interact with electromagnetic waves in space, they can be energised, moved or lost from the radiation belt. Although the interactions have been studied for decades, we were able to make two new breakthroughs as a result of this funded project. (1) Using physics-based numerical simulations, we were able to study the rate and amount of energisation or direction change that electrons experience as a result of interactions with electromagnetic waves. In some situations, rates were very different to those expected using traditional theoretical frameworks. We are now able to devise ways to include these situations in large-scale radiation belt models that provide nowcasts and forecasts. (2) Using years of spacecraft observations, we identified that interactions between waves and electrons are highly variable in time. We quantified this variability and its timescales, and investigated its cause. Most importantly, we then ran numerical experiments to show that because the interactions varied in time, the rate at which electrons were energised, or changed direction, was different than when the interactions were averaged. The rates depend on the timescales of variation. This unexpected result leads to many new research questions that were unanticipated when the research began.
Exploitation Route Both outcomes listed above will be taken forward by teams across the world who model the radiation belts, either to increase physics understanding, or to provide operational space weather forecasts.
Sectors Aerospace, Defence and Marine

 
Description Advisor to European Space Agency
Geographic Reach Europe 
Policy Influence Type Participation in a advisory committee
 
Description Advisor to UK Space Agency
Geographic Reach National 
Policy Influence Type Participation in a advisory committee
 
Title Dataset: Random forest models of ultra-low frequency magnetospheric wave power. 
Description Predictive models of ground-based ultra-low frequency (ULF, 1-15 mHz) wave power, corresponding to magnetospheric waves. The series of decision tree ensembles (random forests) are dependent on solar wind properties, latitude and azimuthal angle around the Earth (magnetic local time, MLT). 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
URL https://zenodo.org/record/3828505
 
Title Dataset: Random forest models of ultra-low frequency magnetospheric wave power. 
Description Predictive models of ground-based ultra-low frequency (ULF, 1-15 mHz) wave power, corresponding to magnetospheric waves. The series of decision tree ensembles (random forests) are dependent on solar wind properties, latitude and azimuthal angle around the Earth (magnetic local time, MLT). 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
URL https://zenodo.org/record/3828506
 
Title Output of 3D model simulating externally driven ULF waves in Earth's magnetosphere, including the effect of convection on plasmaspheric density 
Description This data set contains the ULF wave model output data required to produce the figures in the article: A. W. Degeling, I. J. Rae, C. E. J. Watt, Q. Q. Shi, R. Rankin and Q. G. Zong, "Control of ULF Wave Accessibility to the Inner Magnetosphere by the Convection of Plasma Density", J. Geophys. Res. (accepted Dec. 2017) doi:10.1002/2017JA024874 The dataset has a Matlab binary file format. It consists of a structure array "d" (with 325 elements). These elements correspond to the 2D parameter scan in driver frequency and elapsed time during plume development performed for this study. The elapsed time parameter has 25 elements, ranging 0 to 24 hours (i.e. 1 hour spacing), and the driver frequency parameter has 13 elements ranging from 1 to 7 mHz (with 0.5 mHz spacing). e.g. use "d = reshape(d,25,13);" to reshape the structure array into 2D with columns for the frequency scan and rows for the elapsed time scan. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
 
Title PADIE diffusion coefficients for plasmaspheric hiss 
Description This dataset contains a large number of quasilinear diffusion coefficients that describe the efficacy of wave-particle interactions in the collisionless plasma of Earth's inner magnetosphere. The individual diffusion coefficients are calculated using the PADIE software at the British Antarctic Survey in Cambridge (see Glauert, S. A., and Horne, R. B. (2005), Calculation of pitch angle and energy diffusion coefficients with the PADIE code, J. Geophys. Res., 110, A04206, doi:10.1029/2004JA010851.). Input information (wave intensity and plasma to gyrofrequency ratio) are obtained from co-located and simultaneous observations from Van Allen Probe A as it travelled through a region of space between 0900 and 1000 MLT, and from -5 to +5 degrees magnetic longitude during the period Septemer 2012 - June 2016. There are three locations in L*: L*=2.5+/-0.05; L* = 3.0+/-0.05 and L*=3.5+/-0.05. Diffusion coefficients are calculated separately for each set of co-located measurements, for the mean wave intensity and varying plasma to gyrofrequency ratio, and for the mean plasma to gyrofrequency ratio and varying wave intensity. The distribution of coefficients gives some indication of the variability of the wave-particle interaction due to plasmaspheric hiss and illustrates improvements that can be made to models of wave-particle interactions in Radiation Belt diffusion models. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
 
Title Pitch-angle diffusion experiments to investigate temporal variability of diffusion coefficients 
Description ASCII files documenting the results from a series of numerical experiments using one-dimensional Fokker-Planck equation to study pitch-angle diffusion in Earth's radiation belt for temporally-varying pitch-angle diffusion coefficients. Results from these files were used to obtain Figures 3 and 4 in "The implications of temporal variability in wave-particle interactions in Earth's Radiation Belts", Watt et al., [GRL, 2020] There are two ensemble experiments with temporal variability scale equal to 2 minutes, and 6 hours. The 2 minute ensemble files have naming convention: XX_2minvariation_L3.1d where XX indicates the run number in the ensemble. There are 60 experiments in the ensemble. The 6 hour ensemble files have naming convention: runXX_6hvariation_L3.1d where 1 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
Impact This model is the first to use stochastic parameterization in a space weather context. 
URL https://zenodo.org/record/4290006
 
Description Modeling the acceleration, transport and loss of radiation belt electrons - nonlinear processes 
Organisation ARCHER
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution We proposed for HPC time on ARCHER/ARCHER 2 to conduct numerical experiments. We brought expertise in radiation belt modelling and magnetospheric physics and appropriate time to do the work.
Collaborator Contribution ARCHER contributed HPC facilities and time (3.4M cpuh). Heather Ratcliffe at University of Warwick brought time to help prepare numerical experiments and suggested code modifications for our purposes.
Impact Manuscripts in submission or in preparation
Start Year 2019
 
Description Modeling the acceleration, transport and loss of radiation belt electrons - nonlinear processes 
Organisation University of Warwick
Country United Kingdom 
Sector Academic/University 
PI Contribution We proposed for HPC time on ARCHER/ARCHER 2 to conduct numerical experiments. We brought expertise in radiation belt modelling and magnetospheric physics and appropriate time to do the work.
Collaborator Contribution ARCHER contributed HPC facilities and time (3.4M cpuh). Heather Ratcliffe at University of Warwick brought time to help prepare numerical experiments and suggested code modifications for our purposes.
Impact Manuscripts in submission or in preparation
Start Year 2019
 
Description The nature of wave-particle diffusion in Earth's Outer Radiation Belt 
Organisation Science and Technologies Facilities Council (STFC)
Department Distributed Research Utilising Advanced Computing
Country United Kingdom 
Sector Academic/University 
PI Contribution We provided scientific leadership for work with STFC DIRAC HPC resources
Collaborator Contribution Heather Ratcliffe at University of Warwick has provided technical expertise and software support tailored to our needs.
Impact Results from these numerical experiments are in the review process. This collboration unites space physics (Reading/Northumbria) and numerical plasma simulation modelling (Warwick)
Start Year 2017
 
Description The nature of wave-particle diffusion in Earth's Outer Radiation Belt 
Organisation University of Warwick
Country United Kingdom 
Sector Academic/University 
PI Contribution We provided scientific leadership for work with STFC DIRAC HPC resources
Collaborator Contribution Heather Ratcliffe at University of Warwick has provided technical expertise and software support tailored to our needs.
Impact Results from these numerical experiments are in the review process. This collboration unites space physics (Reading/Northumbria) and numerical plasma simulation modelling (Warwick)
Start Year 2017
 
Description Wave-particle diffusion in the inhomogeneous magnetic fields of the Earth's Outer Radiation Belt 
Organisation Science and Technologies Facilities Council (STFC)
Department Distributed Research Utilising Advanced Computing
Country United Kingdom 
Sector Academic/University 
PI Contribution We led a proposal, and the subsequent work, on a project to perform numerical experiments on wave-particle interactions in Earth's radiation belts.
Collaborator Contribution Heather Ratcliffe at University of Warwick made adjustments to our numerical experiments and provided key expertise. DIRAC provided HPC.
Impact Manuscripts in submission or preparation
Start Year 2018
 
Description Wave-particle diffusion in the inhomogeneous magnetic fields of the Earth's Outer Radiation Belt 
Organisation University of Warwick
Country United Kingdom 
Sector Academic/University 
PI Contribution We led a proposal, and the subsequent work, on a project to perform numerical experiments on wave-particle interactions in Earth's radiation belts.
Collaborator Contribution Heather Ratcliffe at University of Warwick made adjustments to our numerical experiments and provided key expertise. DIRAC provided HPC.
Impact Manuscripts in submission or preparation
Start Year 2018
 
Description Rad-Sat Consortium Meetings 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Semi-annual workshops held for members of consortium and industry stakeholders. Stakeholders discuss importance of space weather to their industry, and we present latest results. Discussions are held regarding future research directions.
Year(s) Of Engagement Activity 2017,2018,2019
 
Description School Visits (Berkshire) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact PI makes multiple individual visits to schools across Berkshire, Hampshire and in London area (KS1-KS5). Presentations made on importance and impact of project, and advertising careers in space sector to pupils, especially focussing on girls' schools. Presentations spark questions and discussion - pupils in KS4-KS5 often blog about visit afterwards, or write article for school newsletter/newspaper.
Year(s) Of Engagement Activity 2017,2018,2019