MIST

Magnetosphere, Ionosphere and Solar-Terrestrial

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A Summary of the SWIMMR Kick-Off Meeting

The kick-off event for the Space Weather Innovation, Measurement, Modelling and Risk Study (one of the Wave 2 programmes of the UKRI Strategic Priorities Fund) took place in the Wolfson Library of the Royal Society on Tuesday November 26th. Seventy-five people attended the event, representing a range of academic institutions, as well as representatives from industry, government and public sector research establishments such as the UK Met Office. 

The morning session of the meeting consisted of five presentations, introducing the programme and its relevance to government, the Research Councils and the Met Office, as well as describing details of the potential calls. The presentations were as follows:

  •  Prof John Loughhead (Chief Scientific Advisor to BEIS) - Space Weather Innovation, Measurement, Modelling and Risk Programme (a governmental perspective). The slides from Prof John Loughhead's talk are available here.
  • Prof Chris Mutlow (Director of STFC RAL Space) - SWIMMR: Project funded by the Strategic Priorities Fund (a perspective from STFC).  The slides from Prof Chris Mutlow's talk are available here.
  • Jacky Wood (Head of Business Partnerships at NERC) - Space Weather Innovation, Measurement, Modelling and Risk (SWIMMR) - A NERC perspective.  The slides from Jacky Wood's talk are available here.
  • Dr. Ian McCrea (Senior Programme Manager for SWIMMR) -  SWIMMR: Space Weather Innovation, Measurement, Modelling and Risk: A wave 2 programme of the UKRI Strategic Priorities Fund.  The slides from Dr Ian McCrea's talk are available here.
  • Mark Gibbs (Head of Space Weather at the UK Met Office) - SWIMMR (Met Office perspective and detailed description of the calls.  The slides from Mark Gibb's talk are available here.

During the lunch break, the Announcement of Opportunity for the five NERC SWIMMR calls was issued on the NERC web site.  The afternoon therefore began with a brief introduction by Jacky Wood to the NERC Announcement of Opportunity, and the particular terms and conditions which it contained.

The remainder of the afternoon session was spent in a Question and Answer session in which attendees were able to ask questions to the speakers about the nature of the programme and the potential timing of future calls, and finally to an informal discussion session, in which participants gathered into groups to discuss the opportunities for funding which had been outlined. 

2019 RAS Council elections

As you may have seen, the nominations for RAS Council are currently open with a deadline of 29 November. MIST falls under the “G” (Geophysics) category and there are up to 3 councillor positions and one vice-president position available. MIST Council strongly encourages interested members of the MIST community to consider standing for election.
 
Clare Watt (University of Reading) has kindly volunteered to be a point of contact for the community for those who may wish to talk more about being on council and what it involves. Clare is a councillor on RAS Council, with her term due to complete in 2020, and This email address is being protected from spambots. You need JavaScript enabled to view it..
 

 

Outcome of SSAP priority project review

From the MIST mailing list:

We are writing to convey the outcome of this year’s priority project “light touch” review, specifically with reference to those projects within the remit of SSAP. We would like to thank all the PIs that originally submitted ideas, and those who provided updates to their projects over the summer. SSAP strongly believe that all the projects submitted are underpinned by strong scientific drivers in the SSAP area.

The “light touch” review was undertaken with a unified approach by SSAP and AAP, considering factors that have led to priority project development (in STFC or other research councils) or new funding for priority projects (1/51 projects in the STFC remit) in the last 12 months. After careful discussion, it was agreed by SSAP and AAP not to select any project where the remit clearly overlaps with UKSA (i.e. space missions or TRL 4+), reflecting STFC’s focus on ground-based observations, science exploitation and TRL 0-3 development. Whilst in no way reflecting the excellence of the science, or community scientific wishes, this approach has resulted in some changes to the list of SSAP priority projects. However, now, unlike at the time of the original call, it is clear that such projects cannot move forwards without UKSA (financial) support, and such funds are already committed according to UKSA’s existing programme. SSAP remain strongly supportive of mission-led science in solar-system exploration, so SSAP have strongly recommended that the high-level discussions between UKSA and STFC continue with a view to supporting a clear joint priority projects call in future, more naturally suited to mission and bi-lateral opportunities.

The priority projects (and PIs) identified by SSAP for 2019/20 are:

  • Solar Atmospheric Modelling Suite (Tony Arber)
  • LARES1: Laboratory Analysis for Research into Extra-terrestrial Samples (Monica Grady)
  • EST: European Solar Telescope (Sarah Matthews)

SSAP requested STFC continue to work with all three projects to expand their community reach and continue to develop the business cases for future (new) funding opportunities. In addition, SSAP have requested that STFC explore ways in which the concept of two projects—“ViCE: Virtual Centres of Excellence Programme / MSEMM Maximising Science Exploitation from Space Science Missions”—can be combined and, with community involvement, generate new funding for science exploitation and maximising scientific return in solar-system sciences. Initially this consultation will occur between SSAP and STFC.

We would like to thank the community again for its strong support, and rapid responses on very short timescales. A further “light touch” review will occur in 2020, with a new call for projects anticipated in 2021. SSAP continue to appreciate the unfamiliar approach a “call for proposals with no funding attached” causes to the community and are continuing to stress to STFC that the community would appreciate clearer guidance and longer timescales in future priority project calls.

Yours sincerely,

Dr Helen Fraser on behalf of SSAP

The Global Network for the Sustainability In Space (GNOSIS)

The Global Network for the Sustainability In Space (GNOSIS) is an STFC Network+ with the goal of helping researchers within the Particle, Nuclear and Astrophysics areas to engage with researchers from other research councils and industry to study the near Earth space environment. For more details, visit the GNOSIS website or see this issue of the GNOSIS newsletter.

Over the next few years we expect a large increase in the number of satellites in Earth orbit. This will lead to unprecedented levels of space traffic much of which will end as debris. The aim of this network is to understand the debris populations and its impact on space traffic management with a view to enabling a safer environment.

The free GNOSIS lunch event will be held on 18 November 2019 at the British Interplanetary Society at Vauxhall, London, with a video link to the Royal Observatory Edinburgh, to facilitate participation from across the UK. Tickets can be obtained here.

GNOSIS will be producing a programme of meetings for both space operations specialists and subject matter novices and will be able to support the development of collaborative ideas through project and part graduate student funding. Details of our first workshop will be announced in the next month.

If you are an academic with no direct experience but have knowledge of areas such as observations, data analysis, simulation or even law, then register your interest on our website. If you are a currently working in the space sector or if you are just interested in the aims and goals of the network please also register your interest and get involved.

SWIMMR: A £19.9M programme of the UKRI Strategic Priorities Fund

Space Weather Instrumentation, Measurement, Modelling and Risk (SWIMMR) is a £19.9M programme of the UK Research and Innovation (UKRI) Strategic Priorities Fund.

MIST would like draw the attention of the research community to the potential opportunities which will become available as a result of this programme, which received final approval from the Department for Business, Energy and Industrial Strategy (BEIS) in August. The programme will run from now until March 2023 and is aimed at improving the UK’s capabilities for space weather monitoring and prediction. UKRI’s Strategic Priorities Fund provides a means for linking research council investment to governmental research priorities, hence the areas being emphasised in the programme reflect space weather threats to critical infrastructure, as reflected in the UK national risk register.

The programme will be delivered jointly by the STFC and NERC, mainly through open grant calls, but including some elements of commissioned work to be delivered through open competitive tenders. The first calls are expected to appear during the coming weeks. More information about the programme is available through the RAL Space website, and is forthcoming from the NERC web site.

To mark the official launch of the programme and provide more details of the planned activities, a kick-off meeting is being held in the Wolfson Library of the Royal Society on Tuesday 26 November 2019, from 10:30. Pre-registration is required for this event and can be done using this link. We hope that many of you will be able to attend.

Nuggets of MIST science, summarising recent MIST papers in a bitesize format.

If you would like to submit a nugget, please contact This email address is being protected from spambots. You need JavaScript enabled to view it. and we will arrange a slot for you in the schedule. Nuggets should be 100–300 words long and include a figure/animation. Please get in touch!

How does substorm activity affect the ring current?

by Jasmine Kaur Sandhu (MSSL, UCL)

Earth’s magnetosphere is highly dynamic and due to coupling with the solar wind huge amounts of energy can be stored in the stretched magnetotail. Substorms (impulsive bursts of nightside reconnection) rapidly close large amounts of the tail flux and, through enhanced convection and injection of plasma, substorms can significantly energise the ring current population.

Do substorms with different properties affect the ring current differently?

Substorms can occur as an isolated event (preceded and followed by quiet periods) or as part of a compound event (multiple substorms occurring one directly after the other). A statistical analysis of ion observations from the Van Allen Probes was conducted to identify the similarities and differences in the ring current population during isolated substorms and the first compound substorm in a sequence. Figure a,b,d,e shows L-MLT maps of the median ring current energy content for both isolated and compound substorms, as well as before substorm onset (growth phase) and after substorm onset (expansion phase). Figure c,f shows statistically significant changes following onset and Figure g,h shows the difference in energy content for compound substorms compared to isolated.

Both types of substorms are associated with an enhancement post-onset, where the total enhancement is larger for a compound substorm. We also observed that the ring current energy content is elevated during compound substorms compared to isolated substorms, both before and after onset. Analysis shows that a key driver of these differences is the enhanced and prolonged solar wind driving prior to onset of compound substorms. Plasma is more effectively circulated to the inner magnetosphere and the density of injections are increased.

Overall the work demonstrates the importance of solar wind driving for the substorm – ring current relationship and suggests that compound substorms are able to very effectively energise the ring current to a high degree.

For more information, please see the paper:

Sandhu, J. K.,  Rae, I. J.,  Freeman, M. P.,  Gkioulidou, M.,  Forsyth, C.,  Reeves, G. D., et al. (2019). Substorm‐ring current coupling: A comparison of isolated and compound substorms. Journal of Geophysical Research: Space Physics,  124. https://doi.org/10.1029/2019JA026766

Plots showing the spatial distribution of ring current energy content.

Figure: Values for each L‐MLT bin are plotted at the bins' location in the L‐MLT domain for the H+ ions. The mean energy values, E (J), are shown for (a) growth phases of isolated substorms, (b) expansion phases of isolated substorms, (d) growth phases of compound substorms, and (e) expansion phases of isolated substorms. The difference in the mean values, ΔE (J), for the expansion phase relative to the growth phase is shown for (c) isolated substorms and (f) compound substorms. The difference in mean values for the compound substorms relative to the isolated substorms is shown for (g) the growth phase and (h) the expansion phase. It is noted that, for the difference plots (c, f, g, h), the difference in mean values is only plotted if the distributions are identified to be statistically different according to the Kolmogorov‐Smirnov test with p<0.01. MLT = magnetic local time.

 

First evidence for multiple-harmonic standing Alfvén waves in Jupiter’s equatorial plasma sheet

By Harry Manners (Imperial College London)

Ultra-low-frequency (ULF) magnetohydrodynamic waves carry energy and momentum through planetary magnetospheres, corresponding to perturbations on large spatial-scales. These perturbations can lead to global oscillations of the magnetic field known as field line resonances (FLRs). While ULF waves and FLRs have been studied extensively in the terrestrial magnetosphere, relatively little literature exists concerning the same phenomena in magnetospheres of the outer planets.

We have used magnetometer data from the Galileo spacecraft to search for ULF wave-power at Jupiter, specifically in the thin, dense equatorial plasma sheet (see panel a of Figure). By removing the background magnetic field we were able to isolate perturbations in the direction transverse to the background field (panel b). We obtained frequency-time information via wavelet transforms of the magnetic-field residuals.

We found evidence for a multiple-harmonic wave structure isolated in the equatorial plasma sheet, on 8th November 1996. Four harmonics were detected, with periods ranging from 4 to 22 minutes (panel c).

We band-pass filtered the transverse field components to obtain a ~1 nT contribution from each harmonic. Subsequent polarization analysis revealed reversals in handedness in each signal consistent with the structure of a multiple-harmonic standing Alfvén wave (panel d). The same analysis suggests all of the detected harmonics are odd modes, with no evidence to support the presence of even modes. We currently have no explanation for the absence of the even modes, but speculate that it is a consequence of the symmetry of the driving mechanism with respect to the magnetic equator.

For more information, please see the paper:

Manners, H. A., & Masters, A. (2019). First evidence for multiple‐harmonic standing Alfvén waves in Jupiter's equatorial plasma sheet. Geophysical Research Letters, 46. https://doi.org/10.1029/2019GL083899

Galileo magnetometer data showing the presence of multiple harmonics and reversals in the handedness.

Figure: a) Magnetic field data from the Galileo spacecraft during 8th November 1996. b) Transverse magnetic field residuals, showing ULF wave packets. c) Wavelet transform of one of the transverse components, showing coincident enhancements in wave power at 22, 14, 7 and 4 minutes. d) Reversals in the handedness of the 22 minute wave signal, consistent with standing Alfvén waves.

 

Timescales of Birkeland Currents Driven by the IMF

By John Coxon (University of Southampton)

Birkeland currents are the mechanism by which information is communicated from Earth’s magnetopause to the ionosphere. Understanding the timescales of these currents is very useful for understanding the ionosphere’s reaction to magnetopause phenomena. We use the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) dataset, which uses magnetometers on 66 spacecraft in low Earth orbit to derive Birkeland current density on a grid of colatitude and magnetic local time. The current densities are derived in a ten minute sliding window, evaluated every two minutes.

We use the SPatial Information from Distributed Exogenous Regression (SPIDER) technique (Shore et al, 2019), which treats each coordinate of a global dataset (e.g. AMPERE or SuperMAG) independently, regressing the time series in each coordinate against some external driver to find the time lag that maximises the correlation of the two. 

The figure below shows the correlation (left) and lag (centre) of the current densities with Interplanetary Magnetic Field (IMF) Bz. We focus on the R1 and R2 regions (right) here. Southward (negative) Bdrives Birkeland current as a result of magnetic reconnection, as shown by the correlations. Looking at the lags on the dayside, the poleward lags are 10–20 minutes, reflecting the time taken for the Birkeland currents to start to react to magnetic reconnection. At all MLT, the equatorward lags are 60–90 minutes, reflecting the time at which the polar cap is largest. On the nightside, the poleward lags are 90–150 minutes, reflecting how long it takes the polar cap to contract during nightside reconnection. More details on the R1/R2 correlations, and other correlations between Birkeland current and IMF Band By, are available in the full study.

For more information, please see the paper: 

Coxon, J. C., Shore, R. M., Freeman, M. P., Fear, R. C., Browett, S. D., Smith, A. W., et al. ( 2019). Timescales of Birkeland currents driven by the IMF. Geophysical Research Letters, 46, 78937901. https://doi.org/10.1029/2018GL081658

Polar plots showing the correlation and lag of AMPERE current density data. A schematic illustrating the key regions is also shown.

Figure: Correlation (left) and lag (centre) of AMPERE current density with IMF Bz in March 2010. A key to the regions visible is presented in the right-hand panel, to allow easy references in the text above.

 

The Impact of Radiation Belt Enhancements on Electric Orbit Raising

By Alexander Lozinski (British Antarctic Survey)

Electric orbit raising is a method of getting satellites into geostationary orbit (GEO) using low-thrust electric propulsion. A satellite intended for GEO is first placed into elliptical geostationary transfer orbit after separating from the launch vehicle. Following this, maneuvers are performed to raise the satellite to GEO. In conventional launches, chemical propulsion is used and this process requires a few days. With electrical thrusters, orbit raising can be performed more efficiently but requires a longer period (around 200 days) due to the lower thrust.

This method of raising satellites was introduced commercially in 2014 with the launch of the first all-electric satellites. Although the lower wet mass due to lack of chemical propellant reduces launch costs, the longer time required for the satellite to reach GEO leaves it exposed to irradiation from trapped protons of the Van Allen belts. This can cause degradation to solar cells via non-ionising displacement collisions.

Sustained enhancements in trapped proton flux can occur via trapping of solar energetic particles following a large geomagnetic disturbance. In this work, the solar cell degradation through time for a variety of real electric orbit raising scenarios was calculated in both a quiet and active environment, based on measurements taken by CRRES before/after the March 1991 storm. The trajectories of two previously launched satellites (EOR-1 and EOR-2) that underwent electric orbit raising is shown in the figure. The figure also shows the calculated remaining output power of the solar cell, P/P0, through time for both trajectories in an active environment. Reductions in P/P0 represent degradation to the solar cells.

A key finding is a large (up to 5%) increase in P/P0 degradation that occurs when electric orbit raising is performed in an enhanced radiation belt environment. However, the figure also demonstrates that some orbits are more at risk than others. Orbits with a higher initial apogee (e.g. EOR-2, red line) spend less time in regions of high proton flux, and experience less degradation. The work highlights the significant impacts of an enhanced environment on solar cell degradation, and identifies how this degradation can in part be mitigated with an appropriate choice of orbit and shielding.

For more information, please see the paper:

Lozinski, A. R., Horne, R. B., Glauert, S. A., Del Zanna, G., Heynderickx, D., & Evans, H. D. R. ( 2019). Solar cell degradation due to proton belt enhancements during electric orbit raising to GEO. Space Weather, 17. https://doi.org/10.1029/2019SW002213

The orbital trajectories are shown for two different satellites, and the corresponding solar cell degradation for the different orbits is also shown.

Figure caption: The left panel shows the remaining power, P/P0, as a function of time for two satellites. The right panels show trajectories of the two satellites over the first 200 mission days.

SuperDARN Observations During Geomagnetic Storms, Geomagnetically Active Times, and Enhanced Solar Wind Driving

by Maria-Theresia Walach (Lancaster University)

At Earth, solar wind coupling drives large scale convection of field lines: antisunward flow of open field lines at high latitudes and the return flow of closed field lines at lower latitudes. This convection can be observed through measurements of the ionosphere, for example using measurements from SuperDARN, an international network of ground based radars, purposely built to study ionospheric convection. We use 7 years of Super Dual Auroral Radar (SuperDARN) data to study ionospheric convection during geomagnetic storms, geomagnetically active times and solar wind driven times. Using the most recent years of SuperDARN data allows us to study ionospheric convection at the mid-latitudes with a field-of-view spanning from the pole to 40 degrees of magnetic latitude.

In this study, we address a number of questions; for example, do we make similar SuperDARN observations during similar solar wind driving during nonstorm time as during storm time? Do SuperDARN observations change throughout the different phases of a storm? Where do we see the fastest flows with SuperDARN, and is it linked to the extent of latitudinal coverage from the radars? Does the latitudinal range of the convection, given, for example, by the return flow region, stay constant throughout a storm? We find that initial and recovery phases of geomagnetic storms show similar convection as enhanced solar wind driving when no geomagnetic storm occurs.

One of the key findings showing the change of regime between the initial, main, and recovery phase of the storm is shown in the figure: it shows the varying relationship between the flow reversal boundary (here FRB but otherwise known as the open-closed field line boundary or polar cap boundary) and the Heppner-Maynard boundary (here HMB, which corresponds to the lower latitude boundary where the ionospheric convection electric field approaches 0 kV). The blue line shows the line of best fit and the data distribution along it, indicates that the boundaries must expand and contract together, however, this happens at different rates during the different storm phases, producing an inflated return flow region during the main phase of the storm. 

For more information, please see the paper below:

Walach, M.‐T., & Grocott, A. ( 2019). SuperDARN observations during geomagnetic storms, geomagnetically active times, and enhanced solar wind driving. Journal of Geophysical Research: Space Physics, 124. https://doi.org/10.1029/2019JA026816

Figure: Colatitude location of the flow reversal boundary (FRB) against the Heppner‐Maynard boundary (HMB) during the three phases of geomagnetic storms (only using maps where n ≥ 200). The dashed black lines show the line of unity and the black contours correspond to where the normalized data point density corresponds to 0.005, 0.01, 0.015, and 0.02.