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!

    The Cushion Region and Dayside Magnetodisc Structure at Saturn

    By Ned Staniland (Imperial College London)

    The moons Enceladus and Io are internal plasma sources for the magnetospheres of Saturn and Jupiter, respectively. This, coupled with their rapid rotation rates (~10 h), radially stretches the magnetic field from a dipole to a magnetodisc. However, this structure can break down at large distances where the magnetic field can no longer contain the equatorial plasma. This quasi-dipolar layer between the current sheet outer edge and magnetopause is known as the “cushion region.” This has previously been observed at Jupiter, predominantly at dawn, but not at Saturn (Went et al., 2011). It is suggested to be populated by mass-depleted flux tubes following magnetotail reconnection.

    We present the first evidence of a cushion region forming at Saturn. From the complete Cassini orbital dataset, only five examples are identified, showing this phenomenon to be rare, with four at local time dusk and one pre‐noon. The dusk cushion observed could be due to asymmetric heating of plasma in the Saturn system (Kaminker et al., 2017), as well as the changing magnetic field configuration through dusk where the field is less confined by the magnetopause, resulting in disc instabilities (Kivelson and Southwood, 2005).

    These results highlight a key difference between the rotationally driven magnetospheres of Saturn and Jupiter. The rare cushion region examples found and evidence of patchy reconnection at Saturn (Delamere et al., 2015) compared to the persistent cushion region at Jupiter (Went et al., 2011) and statistical x-line across the Jovian tail (Vogt et al., 2010) shows that the mass transport and loss mechanisms differ between these systems. Whilst the Saturn system is often described as being between Jupiter and the Earth in terms of dynamics and structure, these results suggest that this is perhaps an oversimplified description.

    An example of a cushion region is shown on the left, where the magnetic field observations indicate a transition from magnetodisc-like to quasi-dipolar. A schematic is included on the right where regions are colour-coded to indicate the expected locations of disc-like and dipolar-like fields.

    Figure: The left plot shows an example of a cushion region at Saturn. The top panel shows magnetic field data. The second panel showing the relative contributions of the radial (green) and meridional (blue) components to the total field. The third panel shows the angle between the observed field and a dipole. For this example, the field is disc-like in the middle magnetosphere, but the structure breaks down in the outer magnetosphere (highlighted by the background colours). The right plot shows the average dayside magnetic field configuration. The field is more disc-like in the dawn sector whilst there is a quasi-dipolar region in the outer magnetosphere at dusk.

    Please see the full paper for details:

    Staniland, N. R., Dougherty, M. K., Masters, A., & Achilleos, N. (2021). The cushion region and dayside magnetodisc structure at Saturn. Geophysical Research Letters, 48, e2020GL091796. https://doi.org/10.1029/2020GL091796

    Particle-In-Cell Simulations of the Cassini Spacecraft's Interaction with Saturn's Ionosphere during the Grand Finale

    By Zeqi Zhang (Imperial College London)

    Cassini's Grand Finale at Saturn was the first time the giant planet’s atmosphere had been sampled in-situ. The ionosphere, and indeed the Saturn system as a whole, provided a uniquely different environment compared to the terrestrial planets and also Jupiter, with populations of charged dust grains influencing the plasma dynamics.  When passing through Saturn’s ionosphere, Cassini observed an ionosphere dominated by ice and dust particles which continually rain inward from Saturn’s vast ring system and soak up free electrons, thus producing a dusty complex plasma.  Understanding how incident plasma currents charge a spacecraft relative to its surrounding environment is important for interpreting the surrounding plasma conditions and on-board plasma measurements.  In this article, we describe three dimensional Particle-In-Cell simulations of the Cassini spacecraft’s interaction with plasmas representative of Saturn's ionosphere during the Grand Finale.

    The global simulations revealed complex interaction features such as a highly structured wake containing spacecraft-scale vortices and electron wings, a Langmuir wave analogue of Alfvén wings, which propagated at small angles to the magnetic field and upstream into the pristine plasma ahead of Cassini. The results explain how a large negatively charged plasma component combined with a large negative to positive ion mass ratio is able to drive the spacecraft to the observed positive potentials, a previously unexplained phenomenon observed during end-of-mission.  Despite the high electron depletions, the electron properties are found as a significant controlling factor for the spacecraft potential together with the magnetic field orientation which induces a potential gradient directed across Cassini's asymmetric body. This study reveals the global spacecraft interaction experienced by Cassini during the Grand Finale in a plasma environment dominated by a class of physics quite different to those considered in the classical view of spacecraft charging.

    Figure shows a schematic of the Cassini spacecraft configuration in the simulation. Bottom panels show the electron, ion, and negative ion density spatial distributions.

    Figure 1. The upper schematic shows the simulation configuration for Cassini during Grand Finale Rev 292 ingress at 2500 km Saturn altitude. The lower panels shows the electron (left-hand panel), ion (centre panel) and negative ion (right-hand panel) densities in the Y-Z plane through Cassini’s main body. The plasma wake is longer for the larger species and electron wing structures are visible in the electron density which propagate at small angles to the ambient magnetic field.

    Please see the paper for full details:

    Zhang, Z., Desai, R.T., Miyake, Y., Usui, H., Shebanits, O., (2021). Particle-In-Cell Simulations of the Cassini Spacecraft’s Interaction with Saturn’s Ionosphere during the Grand Finale. Monthly Notices of the Royal Astronomical Society, Volume 504, Issue 1, pp 964 - 973, https://doi.org/10.1093/mnras/stab750.

    Magnetic topology of actively evolving and passively convecting structures in the turbulent solar wind

    By Bogdan Hnat (University of Warwick)

    Plasma turbulence and magnetic reconnection are fundamental to the transfer of energy and momentum between field and flow and are ubiquitous in laboratory and in space plasmas. Both processes generate coherent structures, which modify the energy transfer between different scales. The precise energy balance depends on the relative prevalence of specific topological structures, their rate of evolution and their ability to carry currents. 

    Multi-point satellite observations of the high Mach number solar wind offer a unique opportunity to directly probe the properties of the coherent structures inherent in plasma turbulence and reconnection. We use topological invariants, nQ and nR, of the magnetic field gradient tensor to classify the topology of magnetic structures and to quantify the prevalence of actively evolving and passively advective structures and their contribution to Ohmic heating. We established that at least 25% of all samples are passively advected by the solar wind. The passive structures are dominated by plasmoids which carry a significant current density. Actively evolving structures are primarily quasi-2D flux ropes and 3D X-points. Magnetic configurations that actively evolve and carry a significant current, give a lower bound on the fraction of structures that can dissipate and heat the plasma to be ~35% of the total population. These are dominated by quasi-2D flux rope topology. Magnetic X-points constitute ~40% of all evolving structures, but only 1/5 of these carry a significant current.

     Probability density distributions are shown for passive structures on the left and active structures on the right. Shaded regions correspond to the topology of the structure.

    Figure 1. Conditional joint probability density for (a) force-free magnetic field, passively advecting configurations; (b) actively evolving magnetic structures. Rectangular blue shaded region with nQ>0 corresponds to quasi-2D flux ropes (O-points). Green shaded region, nQ<0 corresponds to hyperbolic 3D X-point magnetic topologies and unshaded regions represent plasmoids. Magenta line separates regions of hyperbolic and elliptic magnetic field lines.

    Please see the paper for full details:

    Hnat, B., Chapman, S. C., & Watkins, N. W. (2021). Magnetic Topology of Actively Evolving and Passively Convecting Structures in the Turbulent Solar Wind, Phys. Rev. Lett. 126, 125101. https://doi.org/10.1103/PhysRevLett.126.125101  

    Electron Bulk Heating At Saturn’s Magnetopause

    By Matthew Cheng (University College London)

    The magnetopause (MP) boundary is formed by the solar wind plasma flow interacting with a planetary magnetic field. Magnetic reconnection is an important process at this boundary as it energises plasma via release of magnetic energy. This process can lead to an “open” magnetosphere allowing solar wind and magnetosheath particles to directly enter the magnetosphere. At Saturn, the nature of MP reconnection remains unclear. Masters et al. (2012) hypothesised that viable reconnection under a large difference in plasma β across the MP also requires a high magnetic shear (i.e. magnetic fields either side of the boundary close to anti-parallel).

    We used electron bulk heating (i.e. the scalar temperature change) at magnetopause crossings to test hypotheses about reconnection at open magnetopause locations, and the influence of magnetic shear and plasma β. The bulk temperature was determined using three different methods, related to properties of the observed energy distribution (including methods from Lewis et al. 2008). We compared the observed heating of magnetosheath electrons with the prediction based on reconnection, using the semi-empirical relationship proposed by Phan et al. (2013) which relates the degree of bulk electron heating to the inflow Alfven speed. Figure 1 shows that Δβ-magnetic shear parameter space discriminates well between events with evidence of energisation (right) and those without (left). Based on the magnetic shear measured locally by the spacecraft either side of the MP, we find 81% of events with no energisation were situated in the ‘reconnection suppressed’ regime, and up to 68% of events with energization lay in the ‘reconnection possible’ regime. These findings support the hypotheses that magnetic shear and plasma β play a role in the viability of magnetic reconnection.

    Plots showing magnetic shear as a function of delta-beta, showing where events lie in this parameter space. Regions where reconnection is possible and reconnection is suppressed are marked. Two cases are shown: with and without energisation. The plots show the points lying in the suppressed reconnection when there is not energisation. More points lie in the possible reconnection region when there is energisation.

    Figure 1. Assessment of diamagnetic suppression of reconnection, overlaid with electron heating ΔTe. The left and right panels show events without and with evidence of energization respectively.

    Please see the paper for full details:

    Cheng, I., Achilleos, N., Masters, A., Lewis, G., Kane, M., & Guio, P. (2021). Electron Bulk Heating at Saturn’s Magnetopause. Journal of Geophysical Research: Space Physics, 126, e2020JA028800. https://doi.org/10.1029/2020JA028800

    Comparing electron precipitation fluxes calculated from pitch angle diffusion coefficients to LEO satellite observations

    By Jade Reidy (British Antarctic Survey)

    Trapped radiation belt particles can be pitch angle scattered into the loss cone by resonant wave-particle interactions and atmospheric collisions. This high-energy electron input into our atmosphere can affect the atmospheric chemistry and is a significant loss mechanism of particles from the radiation belts, which themselves pose a threat to satellites. Reidy et al (2021) calculates the precipitating flux that would be measured inside the field of view of an electron detector on board a low earth orbiting satellite (POES) using wave particle theory and compares to in-situ data. These calculations depend on diffusion coefficients for whistler mode chorus waves, plasmaspheric hiss waves and atmospheric collisions. The diffusion coefficients used in Reidy et al (2021) were derived for use in the British Antarctic Survey Radiation Belt Model (BAS-RBM). The analysis presented in this paper is a direct test of the how well the diffusion coefficients used in the BAS‐RBM are able to quantify the precipitating flux and therefore a first step toward testing the loss due to precipitation within the BAS‐RBM itself.

    Figure 1 shows a global plot of the linear correlation between the calculated precipitating flux and that measured by the POES T0 >30 keV electron channel between 26–30 March 2013. Our results show the best correlation on the dawnside for L* > 5; this agreement is consistent with chorus waves being the dominant scattering mechanism in this MLT and L-shell zone, suggesting that chorus-driven scattering is well represented in the BAS-RBM. However, we consistently underestimate the precipitating flux on the duskside, suggesting we are likely missing some diffusion here; potential causes of this underestimate are discussed in the paper. Reidy et al (2021) also demonstrates the potential of using wave particle theory to reconstruct the total precipitating flux over the entire loss cone, some of which is missed by the POES detector due to its limited field of view, finding that the total precipitating flux can exceed that measured by POES by a factor of 10.

    A figure showing the correlation between calculated and precipitating flux as a function of space.

    Figure 1: Linear correlation coefficient between calculated and measured precipitating flux in bins of 3 hour MLT and 0.5 L*, where noon is to the top and dawn to the right. The correlation is only shown where the confidence level is over 95%.

    Please see the paper for full details:

    Reidy, J. A., Horne, R. B., Glauert, S. A., Clilverd, M. A., Meredith, N. P., Woodfield, E. E., et al. (2021). Comparing electron precipitation fluxes calculated from pitch angle diffusion coefficients to LEO satellite observations. Journal of Geophysical Research: Space Physics, 126, e2020JA028410. https://doi.org/10.1029/2020JA028410