MIST

Magnetosphere, Ionosphere and Solar-Terrestrial

Latest news

New MIST Council 2021-

There have been some recent ingoings and outgoings at MIST Council - please see below our current composition!:

  • Oliver Allanson, Exeter (This email address is being protected from spambots. You need JavaScript enabled to view it.), to 2024 -- Chair
  • Beatriz Sánchez-Cano, Leicester (This email address is being protected from spambots. You need JavaScript enabled to view it.), to 2024
  • Mathew Owens, Reading (This email address is being protected from spambots. You need JavaScript enabled to view it.), to 2023
  • Jasmine Sandhu, Northumbria (This email address is being protected from spambots. You need JavaScript enabled to view it.), to 2023 -- Vice-Chair
  • Maria-Theresia Walach, Lancaster (This email address is being protected from spambots. You need JavaScript enabled to view it.), to 2022
  • Sarah Badman, Lancaster (This email address is being protected from spambots. You need JavaScript enabled to view it.), to 2022
    (co-opted in 2021 in lieu of outgoing councillor Greg Hunt)

Charter amendment and MIST Council elections open

Nominations for MIST Council open today and run through to 8 August 2021! Please feel free to put yourself forward for election – the voting will open shortly after the deadline and run through to the end of August. The positions available are:

  • 2 members of MIST Council
  • 1 student representative (pending the amendment below passing)

Please email nominations to This email address is being protected from spambots. You need JavaScript enabled to view it. by 8 August 2021. Thank you!

Charter amendment

We also move to amend the following articles of the MIST Charter as demonstrated below. Bold type indicates additions and struck text indicates deletions. Please respond to the email on the MIST mailing list before 8 August 2021 if you would like to object to the amendment; MIST Charter provides that it will pass if less than 10% of the mailing list opposes its passing. 

4.1  MIST council is the collective term for the officers of MIST and consists of six individuals and one student representative from the MIST community.

5.1 Members of MIST council serve terms of three years, except for the student representative who serves a term of one year.

5.2 Elections will be announced at the Spring MIST meeting and voting must begin within two months of the Spring MIST meeting. Two slots on MIST council will be open in a given normal election year, alongside the student representative.

5.10 Candidates for student representative must not have submitted their PhD thesis at the time that nominations close.

SSAP roadmap update

The STFC Solar System Advisory Panel (SSAP) is undertaking a review of the "Roadmap for Solar System Research", to be presented to STFC Science Board later this year. This is expected to be a substantial update of the Roadmap, as the last full review was carried out in 2012, with a light-touch update in 2015.

The current version of the SSAP Roadmap can be found here.

In carrying out this review, we will take into account changes in the international landscape, and advances in instrumentation, technology, theory, and modelling work. 

As such, we solicit your input and comments on the existing roadmap and any material we should consider in this revision. This consultation will close on Wednesday 14 July 2021 and SSAP will try to give a preliminary assessment of findings at NAM.

This consultation is seeking the view of all members of our community and we particularly encourage early career researchers to respond. Specifically, we invite:

Comments and input on the current "Roadmap for Solar System Research" via the survey by clicking here.

Short "white papers" on science investigations (including space missions, ground-based experimental facilities, or computing infrastructure) and impact and knowledge exchange (e.g. societal and community impact, technology development). Please use the pro-forma sent to the MIST mailing list and send your response to This email address is being protected from spambots. You need JavaScript enabled to view it..

Quo vadis interim board

 

A white paper called "Quo vadis, European space weather community" has been published in J. Space Weather Space Clim. which outlines plans for the creation of an organisation to represent the European space weather community.
Since it was published, an online event of the same name was organised on 17 March 2021. A “Quo Vadis Interim Board” was then set up, to establish a mechanism for this discussion, which will go on until June 21st.

The Interim Board is composed of volunteers from the community in Europe. Its role is to coordinate the efforts so that the space weather (and including space climate) European community can:

  1. Organise itself
  2. Elect people to represent them

To reach this goal, the Interim Board is inviting anyone interested in and outside Europe to join the “Quo Vadis European Space Weather Community ” discussion forum.

Eligible European Space Weather Community members should register to the “Electoral Census” to be able to vote in June for the final choice of organisation.

This effort will be achieved through different actions indicated on the Quo Vadis webpage and special Slack workspace.

Call for applications for STFC Public Engagement Early-Career Researcher Forum

 

The STFC Public Engagement Early-Career Researcher Forum (the ‘PEER Forum’) will support talented scientists and engineers in the early stages of their career to develop their public engagement and outreach goals, to ensure the next generation of STFC scientists and engineers continue to deliver the highest quality of purposeful, audience-driven public engagement.

Applications are being taken until 4pm on 3 June 2021. If you would like to apply, visit the PEER Forum website, and if you have queries This email address is being protected from spambots. You need JavaScript enabled to view it..

The PEER Forum aims:

  • To foster peer learning and support between early career scientists and engineers with similar passion for public engagement and outreach, thus developing a peer support network that goes beyond an individual’s term in the forum 
  • To foster a better knowledge and understanding of the support mechanisms available from STFC and other organisations, including funding mechanisms, evaluation, and reporting. As well as how to successfully access and utilise this support 
  • To explore the realities of delivering and leading public engagement as an early career professional and build an evidence base to inform and influence STFC and by extension UKRI’s approaches to public engagement, giving an effective voice to early career researchers

What will participation in the Forum involve?

Participants in the PEER Forum will meet face-to-face at least twice per year to share learning and to participate in session that will strengthen the depth and breadth of their understanding of public engagement and outreach.

Who can apply to join the Forum?

The PEER Forum is for practising early-career scientists and engineers who have passion and ambition for carrying out excellent public engagement alongside, and complementary to, their career in science or engineering. We are seeking Forum members from across the breadth of STFC’s pure and applied science and technology remit.

The specific personal requirements of PEER Forum membership are that members:

  • Have completed (or currently studying for – including apprentices and PhD students) their highest level of academic qualification within the last ten years (not including any career breaks)
  • Are employed at a Higher Education Institute, or a research-intensive Public Sector Research Organisation or Research Laboratory (including STFC’s own national laboratories)
  • Work within a science and technology field in STFC’s remit, or with a strong inter-disciplinary connection to STFC’s remit, or use an STFC facility to enable their own research
  • Clearly describe their track record of experience in their field, corresponding to the length of their career to date
  • Clearly describe their track record of delivering and leading, or seeking the opportunity to lead, public engagement and/or outreach
  • Can provide insight into their experiences in public engagement and/or outreach and also evidence one or more of
  • Inspiring others
  • Delivering impact
  • Demonstrating creativity
  • Introducing transformative ideas and/or inventions
  • Building and sustaining collaborations/networks
  • Are keen communicators with a willingness to contribute to the success of a UK-wide network
  • https://stfc.ukri.org/public-engagement/training-and-support/peer-forum/  

    Nuggets of MIST science, summarising recent papers from the UK MIST community 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, include a figure/animation, and include an affiliation with a UK MIST institute. Please get in touch!

    Transpolar Arcs: Seasonal Dependence Identified by an Automated Detection Algorithm

    By Gemma E Bower (University of Leicester)

    Transpolar arcs (TPAs) are primarily a northward IMF auroral phenomena. They consist of an arc of auroral emission poleward of the main auroral oval. Their presence suggests that the magnetosphere has a complicated magnetic topology. Currently, TPA formation and evolution have no single explanation that is unanimously agreed upon.

    In order to further study the occurrence of TPAs we have developed an automated detection algorithm to determine the occurrence of TPAs in UV images captured by the Defense Meteorological Satellite Program/ Special Sensor Ultraviolet Spectrographic Imager (DMSP/SSUSI) from spacecraft F16, F17, and F18. The detection algorithm identified TPAs as a peak in the average radiance intensity poleward of 12.5° colatitude, in two or more of the wavelengths/bands sensed by SSUSI.

    Over 5,000 SSUSI images containing TPAs were identified by the detection algorithm between the years 2010 to 2016. Figure 1a and b shows the seasonal and UT distribution for the F16 TPA images respectively. The occurrence of these TPA images shows a seasonal dependence, with more arcs being visible in the winter hemisphere.  There is also an apparent dependence on time-of-day, especially in the southern hemisphere where no TPAs are seen between 23 and 06 UT.

    We investigated the effect that the orbital plane of DMSP has on the area of the detection window scanned, as a possible explanation of the dependences in the results of the detection algorithm. Figure 1c and 1d show the results for F16 for seasonal and UT distribution respectively. It can be seen that the orbital plane of DMSP leads to a preferential observation of the northern hemisphere, and the detection algorithm missing TPAs in the southern hemisphere around 01–06 UT. Hence, we conclude that there is no dependence of TPA occurrence on UT. No seasonal bias in the observations is found, indicating that the seasonal dependence of the TPA occurrence is real. We discuss the ramifications of these findings in terms of proposed TPA generation mechanisms.

    Four bar charts showing the number of transpolar arcs identified between 2010 and 2016.

    Figure 1: (a-b) Number of transpolar arc (TPA) images identified by F16 between 2010 and 2016. (c-d) Average percent of the detection window poleward of 12.5° colatitude scanned by F16 between 2010 and 2016. (a and c) By month. (b and d) By UT. The northern hemisphere is red and the southern hemisphere is blue

     

    Please see paper for full details: Bower, G. E., Milan, S. E., Paxton, L. J., & Imber, S. M. (2022). Transpolar arcs: Seasonal dependence identified by an automated detection algorithm. Journal of Geophysical Research: Space Physics, 127, e2021JA029743. https://doi.org/10.1029/2021JA029743

    Variation of Geomagnetic Index Empirical Distribution and Burst Statistics Across Successive Solar Cycles

    By Aisling Bergin (University of Warwick)

    Geomagnetic indices, based on magnetic field observations at the Earth's surface, provide almost continuous monitoring of Earth’s magnetospheric and ionospheric activity. We analyze two geomagnetic index time series, AE and SMR, which track activity in the auroral region and around the Earth's equator, respectively. We show here that quantiles of the index distributions track solar cycle variation over solar cycles 21–24. The question is then how the likelihood of events varies with solar cycle activity.

    In this paper, events are defined as bursts or excursions above a threshold which is either (i) a fixed value or (ii) a quantile of the distribution of the observed index values. We study the solar cycle dependence of the distributions of the burst return periods, R, and the burst durations, τ. A result from the theory of level crossings (LC) [1] constrains how , the ratio of the mean burst duration to return period, depends on the underlying empirical distribution of the observed quantity.

    Our main results are as follows:

    1. At fixed value burst thresholds, is peaked in the declining phase for AE annual samples and follows the sunspot number double peak for SMR.
    2. Bursts are identified in samples at three distinct phases of the solar cycle. At fixed quantile thresholds the distributions of τ and R fall on single empirical curves for each of (i) the AE index at solar minimum, maximum, and declining phase and (ii) the SMR index at solar maximum. This goes beyond the constraint on average from LC theory.
    3. The tail of the empirical cumulative distribution functions of the observed values of the AE and SMR indices collapse onto common functional forms specific to each index and cycle phase when normalized to the first two moments of their exceedance distributions.

    Taken together, these results may combine to offer important constraints in the quantification of overall space weather activity levels.

     

    Three panels showing how the theory of level crossings relates the empirical cumulative distribution function (cdf) to the ratio of the mean duration to mean return period for bursts above a specified threshold in a timeseries.
    The theory of level crossings relates the empirical cumulative distribution function (cdf) to the ratio of the mean duration to mean return period for bursts above a specified threshold in a timeseries. Panels (a) - (c) illustrate this relationship for the SuperMAG 1-min ring current index (SMR) from 1975 to 2017. (a) Cdf values, C(x), and highlighted quantiles of interest (black lines) for nonoverlapping 1-year (-)SMR samples are seen to track the 13-month smoothed monthly sunspot number (red, shifted). (b) Bursts (grey) are identified where the SMR index (black) is below a given threshold, u (blue). Burst parameters duration (τ) and return period (R) are quantified. (c) The ratio of mean burst duration to mean return period for bursts in nonoverlapping 1-year (-)SMR samples over thresholds of 40 nT (purple), 60 nT (blue), and 100 nT (green) follows the sunspot number double peak (grey).

    Please see the paper for full details: Bergin, A., Chapman, S. C., Moloney, N. R., & Watkins, N. W. (2022). Variation of geomagnetic index empirical distribution and burst statistics across successive solar cycles. Journal of Geophysical Research: Space Physics, 127, e2021JA029986. https://doi.org/10.1029/2021JA029986

    [1] Lawrance, A., & Kottegoda, N. (1977). Stochastic modelling of riverflow time series. Journal of the Royal Statistical Society: Series A, 140(1), 1–31. https://doi.org/10.2307/2344516

    Saturn's Weather‐Driven Aurorae Modulate Oscillations in the Magnetic Field and Radio Emissions

    By Nahid Chowdhury (University of Leicester)

    Planetary parameters at Saturn have exhibited mysterious time variabilities and periodicities for almost two decades. After the first Voyager measurements of the 1980s led to a determination of a rotation rate for the ringed planet, the advent of the Cassini mission in the 2000s showed that the measured length of a day at Saturn was subject to change. Numerous theories were proposed to explain the time variabilities seen in planetary parameters ranging from the radio emission through to the energies of neutral atoms and these fell into one of two general categories. The first was that a driving mechanism for the observed periodic behaviour would be situated externally to the planet, within the magnetosphere. The second was that a driving mechanism would be situated within the planet’s atmosphere.

    Using infrared observations of Saturn’s northern polar auroral H3+ emission taken with Keck-NIRSPEC in 2017, we investigated ion flows in our search for a signature of the twin-vortex mechanism in the planet’s upper atmosphere that was purported to drive the observed periodicities. H3+ is an ion found in the ionosphere of gas giant planets and measurements of its line-of-sight velocity are indicative of the more general motion of constituents in the planet’s atmosphere.

    By grouping our spectral data into quadrants of local northern planetary magnetic phase, we set up our experiment to probe the ion flows driven by the planetary period current. This led to the astonishing detection of the proposed ionospheric twin-vortices that are considered to be responsible for the periodicities witnessed throughout Saturn’s planetary and magnetospheric environments. Our observations show that local atmospheric weather effects at Saturn drive the twin-vortex flows while also generating some auroral emissions. This result has far-reaching implications for both other planets in our Solar System and exoplanetary systems.

     

    Figure caption: Shown here is an example of the type of winds within the upper atmosphere that are driving the ionosphere to move in the way observed in this new paper. This set of two vortices rotate around the pole of the planet, driving currents within the ionosphere, which then reach out into the surrounding magnetosphere, producing the bright aurora and magnetic field changes observed by Cassini. This weather system was originally proposed by Chris Smith in a paper in Monthly Notices of the Royal Astronomical Society in 2011 (doi:10.1111/j.1365-2966.2010.17602.x) – and it is these modelled flows that we show here.

    Please see paper for full details: Chowdhury, M.N., Stallard, T.S., Baines, K.H., Provan, G., Melin, H., Hunt, G.J., Moore, L., O’Donoghue, J., Thomas, E.M., Wang, R. and Miller, S., 2022. Saturn's Weather‐Driven Aurorae Modulate Oscillations in the Magnetic Field and Radio Emissions. Geophysical Research Letters49(3), p.e2021GL096492. DOI: https://doi.org/10.1029/2021GL096492.

    Modelling the Varying Location of Field Line Resonances During Geomagnetic Storms

    By Tom Elsden (University of Glasgow)

    Field line resonances (FLRs) are the manifestation of a magnetohydrodynamic (MHD) wave coupling process where energy is transferred from a global to local field-aligned wave. The ‘resonance’ comes from a frequency matching between these waves and being a resonant process, can result in a significant accumulation of energy on a given field line. These waves play an important role in magnetospheric wave-particle interactions, the generation of aurora and can further be used as a seismological tool to remote sense the magnetosphere from ground-based observations.

    The location where FLRs occur is intrinsically linked to the current state of the magnetosphere, with the magnetic field structure, plasma density and solar wind driving conditions all being key factors. Given the drastic effect of a geomagnetic storm on the morphology of the magnetosphere, we considered how such changes impact where FLRs form between storm and non-storm times.

    We used ground magnetometer data to determine how the fundamental Alfven frequency of field lines varies over the course of a storm on average. These frequencies were then used to infer a plasma density profile to be used in a numerical MHD model to investigate where the FLRs would form under broadband solar wind driving conditions.

    Figure 1 shows results from these simulations, displaying the field-aligned current density as an indication of FLRs, mapped from the ionosphere to the equatorial plane to display the radial structure. The left panel is from a simulation modelling the initial phase of a storm, with the right panel modelling the main phase. We show that for an average storm, the FLR moves radially inward by ~1.7RE (compare vertical line locations). This is caused by a decrease in the fundamental Alfven frequency as well as an increase in the global (fast) wave frequency which drives the FLRs.

    The important aspect of the results is the overall trend of more Earthward FLR formation during storms. Particularly if extrapolated to more severe storms, this could have an impact on storm-time wave-particle interactions in the radiation belts.

     Colour contours of field-aligned current density from near the ionospheric end of field lines, mapped to the equatorial plane. Left: simulation modelling storm initial phase. Right: simulation modelling storm main phase. Vertical lines indicate field line resonance locations.

    Figure 1 Caption: Colour contours of field-aligned current density from near the ionospheric end of field lines, mapped to the equatorial plane. Left: simulation modelling storm initial phase. Right: simulation modelling storm main phase. Vertical lines indicate field line resonance locations.


    Please see paper for full details: Elsden, T., Yeoman, T. K., Wharton, S. J., Rae, I. J., Sandhu, J. K., Walach, M.-T., et al. (2022). Modeling the varying location of field line resonances during geomagnetic storms. Journal of Geophysical Research: Space Physics, 127, e2021JA029804. https://doi.org/10.1029/2021JA029804

     

    Resolving Magnetopause Shadowing Using Multimission Measurements of Phase Space Density

     By Frankie Staples (formerly at MSSL UCL, now at UCLA)

    Loss mechanisms act independently or in unison to drive rapid loss of electrons from the radiation belts. Electrons may be lost by precipitation into the Earth’s atmosphere, or through the magnetopause into interplanetary space – a process known as magnetopause shadowing. The mechanisms by which electrons are lost may be identified through changes to electron phase space density (PSD). This method considers the number of particles at given adiabatic coordinates (𝝁, K, and L*), which relate the electron energy, pitch angle, and location in the magnetic field. The characteristics of PSD evolution as a function of L* can be used to identify which loss mechanism is acting. However, the rapid nature of electron flux dropouts make it extremely difficult to resolve PSD dynamics at the necessary timescales to identify the contributions of either loss mechanism.

     

    In this study we used a new multimission dataset of PSD observations from 36 satellites to resolve the dynamics of a magnetopause shadowing induced flux dropout in September 2017. We showed that by using Van Allen Probe data alone, the physical processes causing the dropout could be misinterpreted due to limited time and/or spatial resolution. Using multimission observations provided unprecedented time and spatial resolution necessary to correctly interpret PSD dynamics. 

     

    The labelled Figure shows the magnetopause shadowing characteristics identified in PSD observations. Each panel shows PSD as a function of L* for fixed μ = 900 MeV/G and K = 0.1 G0.5RE at 1-hour intervals through phases of the storm. Symbol colours indicate when measurements were taken within the hour period, and dotted lines show the minimum and maximum L* of the last closed drift shell (LCDS) before the magnetopause. 

     A figure showing three scatter plots. The labelled Figure shows the magnetopause shadowing characteristics identified in PSD observations. Each panel shows PSD as a function of L* for fixed μ = 900 MeV/G and K = 0.1 G0.5RE at 1-hour intervals through phases of the storm.

    Please see paper for full details: 

    Staples, F. A., Kellerman, A., Murphy, K. R., Rae, I. J., Sandhu, J. K., & Forsyth, C. (2022). Resolving magnetopause shadowing using multimission measurements of phase space density. Journal of Geophysical Research: Space Physics, 127, e2021JA029298. https://doi.org/10.1029/2021JA029298