Magnetosphere, Ionosphere and Solar-Terrestrial

Latest news

RAS Specialist Discussion suggestions invited

The RAS is inviting suggestions from Fellows of the RAS for Specialist Discussion meeting topics in the academic year 2019/20. These meetings are held on the second Friday of the month between October and May in a given academic year; the April meeting will be moved due to the second Friday being Good Friday. 

If you would like to organise one of these meetings, you can do so by submitting a proposal no longer than one A4 page. Geophysics proposals, including MIST science, should be sent to This email address is being protected from spambots. You need JavaScript enabled to view it., and the deadline is 1 March 2019.

Your proposal should include the title of the meeting; the names of the co-convenors (at least one of whom should be a RAS Fellow); the topics you intend to cover; the rationale (including timeliness); suggestions for invited speakers; and the preferred date for the meeting. More information, including detailed guidance, can be found on the RAS website.


RAS awards for 2019 announced

MIST Council would like to extend their congratulations to the 2019 Royal Astronomical Society award winners, as well as the recent AGU award winners. In particular, we congratulate the following MIST members recognised for their significant achievements:
  • Margaret Kivelson (UCLA) has been awarded the Gold Medal in Geophysics for a lifetime of outstanding achievement in understanding planetary magnetospheres and their connections to the planets they surround.
  • Tom Stallard (Leicester) has been awarded the Chapman medal in Geophysics for outstanding contributions to understanding planetary upper atmospheres and their interactions with their magnetospheres.
  • The Cluster Science and Operations Team have been awarded the Geophysics Group Award for their continued success ensuring the operations and scientific exploitation of the European Space Agency’s Cluster mission.
  • Mark Clilverd (British Antarctic Survey) has been awarded the James Dungey Lecture for their excellent research on energetic particle precipitation and its effects on the upper atmosphere and climate, and their vast experience delivering outstanding scientific talks to a broad range of audiences.
  • Julia Stawarz (Imperial College London) has been awarded the Basu United States Early Career Award for Research Excellence in Sun-Earth Systems Science for significant contributions in furthering understanding of collisional plasma turbulence and kinetic scale processes. 
MIST Council would also like to congratulate Fran Bagenal (Colorado), who has been awarded the AGU Van Allen Lecture for exceptional work on the understanding of planetary magnetospheres and outstanding contributions to planetary missions.

New community resources now available

MIST Council are pleased to announce three resources for the MIST community on the MIST website.

List of research groups

The list of MIST research groups has been updated to include the latest members of the MIST community, and to incorporate the latest links to their presences online. Old groups, or groups at institutions which have merged since the original list was written, are now excised, and the list should be an exhaustive and up-to-date list of British MIST institutions.

List of seminar speakers

We asked the MIST community to come forward and be listed on our list of seminar speakers, and the uptake has so far been very encouraging. The list ranges from relatively junior PhD students to academics at various institutions, and if you're arranging seminars for your research group, we would encourage you to take a look.

List of public engagement projects

Following the success of the recently-held Public Engagement in MIST (MIST+PE) symposium, there was an appetite for MIST Council to better advertise the public engagement being done at MIST institutions across the UK. The Public Engagement page on the MIST website aims to advertise the MIST community's strengths to the rest of the community.

If you spot omissions on any of the above pages, or would like us to include content, please This email address is being protected from spambots. You need JavaScript enabled to view it..

New mailing list for Python in space science

A new mailing list for space scientists who use Python has been founded. Angeline Burrell writes: 

There's been a recent push for more community python development and peer-to-peer support. Much of this is focused in the US at the moment, but as the results of the recent survey showed, MIST scientists are active or interested in python as well. If you would like to become involved, you can join the email list by contacting This email address is being protected from spambots. You need JavaScript enabled to view it..

The mailing list will comprise discussion as well as webinars/telecons from Python users, so the list should be useful for a range of abilities with Python. To join, please email This email address is being protected from spambots. You need JavaScript enabled to view it..

New MIST forum via Slack

In the days of yesteryear, there was a MIST forum provided for members of the MIST community to discuss things in a fashion more immediate and informal than email. It has been some years since the fabled MIST forum was a going concern, and in that time, the MIST Council has technically been in violation of the MIST Charter, which states that

MIST will provide an on-line forum to allow ongoing discussions and the formulation of ideas prior to public dissemination. This forum will be private, visible only to registered members; membership is restricted to active MIST scientists and is offered at the discretion of MIST council chair.

As a result of realising that the Charter mandates the maintenance of a forum, MIST Council have chosen to create a Slack workspace for the MIST community. If you would like to join, please This email address is being protected from spambots. You need JavaScript enabled to view it. specifying the email address you would like to use, and you will be invited to join.

Shapes of Electron Density Structures in The Dayside Mars Ionosphere

By Catherine Diéval, Department of Physics, Lancaster University, UK.

The dayside Mars ionosphere is thought to be reasonably well understood (see e.g. a review by Withers, 2009). The top of the ionosphere is influenced, among various factors, by localized crustal magnetic fields (e.g. Acuña et al., 1999), solar EUV and solar wind input, in the absence of a global magnetic moment. However a peculiar ionospheric feature is still the subject of ongoing research: non-horizontal electron density structures are regularly observed in localized areas with strong and near vertical crustal magnetic fields, in the topside ionospheric levels remotely sampled by the MARSIS radar (Picardi et al., 2004) onboard the Mars Express orbiter (e.g. Andrews et al. 2014; Diéval et al., 2015; Duru et al., 2006; Gurnett et al., 2005). These structures are detectable via oblique echoes returned to the radar after it sends a radio wave pulse through the ionosphere.The reflectors often appear at higher apparent altitude than the surrounding ionosphere, and so are nicknamed "bulges".

Previous studies also used radar returns uncorrected for signal dispersion. Actually, the group velocity of the radio waves varies with the refractive index of the plasma layers encountered, until reflection occurs. The apparent ranges of the received echoes are calculated using the time delays of the echoes and assuming the speed of light in vacuum. However this leads to overestimating the ranges,so interpretations on the shape of the structures based on these are uncertain.

Our work (Diéval et al., 2018), is a statistical study using timeseries of electron density profiles (electron density function of altitude, corrected for signal dispersion) to study the shape of 48 structures, in their full frequency (thus altitude) range, during the period that Mars Express passes over them.

Figure 1 shows that at any frequency, the most frequent shape is the bulge, dwarfing three other types of detected shapes: dips, downhill slopes and uphill slopes. All these shapes are inclined, thus able to reflect oblique echoes. Interestingly, bulges were reproduced in simulation results of Matta et al. (2015).

For more information, see the paper below:

Diéval, C., Kopf, A. J., & Wild, J. A. (2018). Shapes of magnetically controlled electron density structures in the dayside Martian ionosphere. Journal of Geophysical Research: Space Physics, 123, 3919–3942. https://doi.org/10.1002/2017JA025140

Figure 1: Distribution of the four simplest shapes of structures as a function of frequency, for the 48 events, displayed as colored symbols: bulges (red dots), dips (black diamonds), uphill slopes (blue ‘x’), downhill slopes (green ‘+’). Data points at frequency levels within in the sensitivity gaps are not displayed.

Plasma Heating From Dipolarizations in Saturn's Magnetotail

By Andrew Smith, Department of Physics and Astronomy, University of Southampton, UK.

Magnetic reconnection in a planet's magnetotail allows the stretched field to snap back towards the planet, carrying with it a bundle of plasma.  This is known as a dipolarization front, which often manifest in spacecraft data as rapid rotations of the magnetic field accompanied by a change in the local plasma character.  Dipolarization fronts have been observed at Earth, Mercury, Jupiter and Saturn and are thought to be linked to bright auroral displays.

We performed a large automated survey of Cassini data, identifying 28 intervals when the spacecraft was in the path of dipolarization fronts sweeping towards Saturn.  The changes in plasma properties were investigated, along with the supra-thermal composition.  A large dawn-dusk asymmetry was present in the observations, with 79% of the events located post-midnight.  Figure 1 shows the change in plasma characteristics from that preceding the front (a) to within the dipolarizing material (b).  All of the identified events showed an increase in the electron temperature and a coupled reduction in the electron density.  Figures 1c and (d) show the relative change in temperature and density respectively.  Overall, the temperature was found to increase by factors between 4 and 12, while the density dropped by factors of 3-10.  The variable plasma properties are thought to be linked to a variable reconnection location, particularly post-midnight.

Figure 1: Panels (a) and (b) show the electron density plotted aainst the electron temperature for before (a) and after (b) the dipolarization front.  These panels are plotted on the same axes scale for direct comparison.  The gray lines indicate how the events move in density-temperature space.  Panels (c) and (d) show the electron temperature and density (respectively) before the front plotted against the electron temperature and density after the passage of the front.  The points and error bars provided are the mean and standard error of the mean respectively.  The diagonal black dashed line shows the location of $y = x$: where the points would lie if there was no change following the passage of the front.  The red dashed lines indicate least squares linear fits to the data; the details of the fit parameters are provided on the panels.  The color bar for all four panels indicates the radial distance at which the spacecraft encountered the event.


For more information, see the paper below:

Smith, A. W., Jackman, C. M., Thomsen, M. F., Sergis, N., Mitchell, D. G., & Roussos, E. (2018). Dipolarization fronts with associated energized electrons in Saturn's magnetotail. Journal of Geophysical Research: Space Physics, 123, 2714–2735. https://doi.org/10.1002/2017JA024904

The Association of High‐Latitude Dayside Aurora With NBZ Field‐Aligned Currents

By Jennifer Carter, Department of Physics and Astronomy, University of Leicester, UK

Under northward interplanetary magnetic field conditions, when the IMF Bz > 0 nT, non-filamentary auroral emissions may be seen within the dayside polar cap and separate from the main auroral oval. These emissions are associated with lobe reconnection occurring at the high-latitude magnetopause on open field lines. Two mechanisms have been proposed to explain these emissions. The first involves the precipitation of magnetosheath plasma at the footprint of the high-latitude reconnection site, resulting in a “cusp spot”. This cusp spot has been shown to move in response to the east-west (BY) orientation of the solar wind. The second mechanism associates the auroral emissions known as High-Latitude Detached Arcs (HiLDAs) with upward field-aligned currents inside the polar cap. Under northward IMF, twin-cell field-aligned currents (NBZ system) can be found inside of the main region 1-region 2 field aligned current system. Under the influence of positive IMF BY, the upward NBZ cell expands across the noon sector in the Northern Hemisphere, whereas under negative BY, the downward cell will enlarge. The reverse scenario occurs in the Southern Hemisphere for either BYdirection.

Previous observations of HiLDAs have been limited to the Northern Hemisphere for a small data set, and previous authors have linked this phenomenon to season, as the HiLDAs have only been detected during the summer. We used concurrent auroral observations from Defense Meteorological Satellite Program Special Sensor Ultraviolet Spectrographic Imager (SSUSI) experiment, and FAC distributions constructed from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE), from the Iridium telecommunication satellite constellation, to perform a large statistical study of HiLDAs under varying IMF for both hemispheres. We observe a patch of auroral emission that is co-located with the upward NBZ FAC in the dayside polar cap in both the Northern and Southern Hemispheres under northward IMF conditions.

We observe the HiLDA emission to move in response to changes in the IMF BYcomponent (e.g. Figure 1), whereby the HiLDAs are seen to move into the polar cap under positive BY, or be pushed up against, and therefore indiscernible from, the main auroral oval under negative BY(Northern Hemisphere case). We also support the hypothesis that these emissions are only detectable in the summer hemisphere, indicating a dependence on ionospheric conductivity via photoionisation in the predominantly sunlit hemisphere.

For more information, see the paper below:

Carter, J. A., Milan, S. E., Fogg, A. R., Paxton, L. J., & Anderson, B. J. (2018). The association of high‐latitude dayside aurora with NBZ field‐aligned currents. Journal of Geophysical Research: Space Physics, 123. https://doi.org/10.1029/2017JA025082

Figure 1: Northern Hemisphere summer auroral emissions in the Lyman-Birge-Hopfield long band with overlaid field-aligned current contours, for the Northern (N, row a) and Southern (S, row b) Hemispheres. Clock angles are given in the left-hand column. Interplanetary magnetic field magnitudes are between 5 and 10 nT. Field-aligned current contours are overlaid for upward (red) and downward (turquoise) currents, at absolute magnitudes of 0.1 (solid line), 0.3 (dashed line), and 0.5 (dotted line) μA/m2.


Submit a new nugget

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!

Solar Wind Dependence of Magnetospheric Ultra-Low Frequency Plasma Waves

By Sarah Bentley, Department of Meteorology, University of Reading, UK

Ultra-low frequency plasma waves (ULF, 1-15 mHz) are implicated in the energisation and transport of radiation belt electrons. Therefore a description of magnetospheric ULF wave power in terms of driving parameters is highly desirable for radiation belt forecasting; in particular, we want to describe power in terms of solar wind properties, as the solar wind is the dominant driver behind these waves.

However, identifying solar wind driving parameters is severely hampered by the nature of the solar wind. All solar wind parameters are highly interrelated due to their common solar sources and the interactions within the solar wind between the Sun and Earth, resulting in the effect that all solar wind properties correlate so strongly with speed vswthat investigating their relationship to magnetospheric properties is difficult.

To circumvent analysis techniques that require properties such as a linear interdependence between these parameters, we use a series of simple yet systematic two-parameter plots (e.g. Figure 1) to identify which parameters are causally correlated to ULF wave power, rather than just correlated via a relationship with speed vsw. We find that speed, the southward component of the interplanetary magnetic field and summed power in proton number density perturbations (vsw, Bz < 0 and δNp) are the three dominant parameters driving power in magnetospheric ultra-low frequency waves. These parameters can be used in future modelling but are also of interest because there is clearly a threshold at Bz = 0, and because ULF wave power depends more on perturbations δNp than the number density Np itself.

For more information, see the paper below or an informal blog post here.

Bentley, S. N., Watt, C. E. J., Owens, M. J., & Rae, I. J. (2018). ULF wave activity in the magnetosphere: Resolving solar wind interdependencies to identify driving mechanisms. Journal of Geophysical Research: Space Physics, 123. https://doi.org/10.1002/2017JA024740

Figure 1: A two-parameter plot taken from Bentley et al., 2018. We bin the ULF power observed at one station (roughly corresponding to geostationary orbit) at one frequency (2.5mHz) and observe whether it increases with increases in solar wind speed vswand/or the component Bz of the interplanetary magnetic field, using fifteen years of data. Cut-throughs at constant speed and Bz are shown in (b) and (c). ULF power increases with speed and with more strongly negative Bz for Bz<0, but only with speed for Bz>0.