Magnetosphere, Ionosphere and Solar-Terrestrial

Latest news

RAS Awards

The Royal Astronomical Society announced their award recipients last week, and MIST Council would like to congratulate all that received an award. In particular, we would like to highlight the following members of the MIST Community, whose work has been recognised:
  • Professor Nick Achilleos (University College London) - Chapman Medal
  • Dr Oliver Allanson (University of Birmingham) - Fowler Award
  • Dr Ravindra Desai (University of Warwick) - Winton Award & RAS Higher Education Award
  • Professor Marina Galand (Imperial College London) - James Dungey Lecture

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.

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!

Finding the Magnetopause Standoff Distance Using a Soft X-Ray Imager

By Andrey Samsonov (University College London)

The magnetopause standoff distance characterizes global magnetospheric compression and deformation in response to changes in the solar wind dynamic pressure and interplanetary magnetic field. We cannot derive this parameter directly from in situ spacecraft measurements because spacecraft cross the magnetopause rarely and in different regions along the magnetopause surface. However, it will be possible to obtain the time series of the magnetopause standoff distance in the near future using observations by soft X-ray imagers. In two companion papers (see below), we describe methods of finding the standoff distance from X-ray images. Soft X-rays are emitted in the magnetosheath and cusps as a result of charge exchange between heavy solar wind ions and exospheric neutrals. We use the results of MHD simulations to calculate the X-ray emissivity for different solar wind conditions. We simulate an artificial case with constant solar wind conditions and a case with an interplanetary coronal mass ejection (ICME) observed by the Wind spacecraft on 16-17 June 2012. Some MHD models predict relatively high density in the magnetosphere, larger than observed in the data. Correcting this, we develop magnetospheric masking methods to separate the magnetosphere from the magnetosheath and cusps.

We use the SXI_SIM numerical code developed at the University of Leicester to simulate the expected output of the Soft X-ray Imager (SXI) on board the forthcoming Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) mission. Using the MHD results as input conditions, this code calculates the integrated emissivity along the Line-of-Sight (Ix) and SXI counts maps (see Figure 1). We verify the assumption that the maximum of the integrated emissivity is tangent to the magnetopause. Overall, the magnetopause is located close to the maximum Ix gradient or between the maximum Ix gradient and the maximum Ix depending on the method used. But since the angular distance between the maximum Ix gradient and the maximum Ix is relatively small (about 3°), the maximum Ix might be used as an indicator of the outer boundary of a wide magnetopause layer usually obtained in MHD simulations.


Eight panels showing the integrated emissivity and SXI count maps for different times during an ICME interaction with the magnetosphere. The emissivity is at first very bright and reliable due to the high number count, and then decreases.
Figure 1. Integrated emissivity (a,c,e, and g) and SXI counts maps (b,d,f, and h) with the exposure time of 5 min for different times in the case when an ICME interacts with the magnetosphere.

Original articles for further detail:

Samsonov, A., Carter, J. A., Read, A., Sembay, S., Branduardi-Raymont, G., Sibeck, D., & Escoubet, P. (2022). Finding magnetopause standoff distance using a soft X-ray imager: 1. Magnetospheric masking. Journal of Geophysical Research: Space Physics,

127, e2022JA030848. https://doi.org/10.1029/2022JA030848

Samsonov, A., Sembay, S., Read, A., Carter, J. A., Branduardi-Raymont, G., Sibeck, D., & Escoubet, P. (2022). Finding magnetopause standoff distance using a Soft X-ray Imager: 2. Methods to analyze 2-D X-ray images. Journal of Geophysical Research: Space Physics, 127, e2022JA030850. https://doi.org/10.1029/2022JA030850

LOFAR Observations of sub-structure within a Travelling Ionospheric Disturbance at mid-latitude

By Gareth Dorrian (Space Environment & Radio Engineering, University of Birmingham)

Travelling ionospheric disturbances (TID) are ubiquitous wave-like propagations in the Earth’s ionosphere and are the ionospheric counterpart of neutral atmospheric gravity waves (AGW). AGW can be driven by numerous sources from both the terrestrial and space weather domain such as sunrise, auroral sub-storms, volcanic eruptions, or thunderstorms. Terrestrial drivers from the lower atmosphere are coupled to the thermosphere by upwards propagation of AGW (Hines, 1960).

We study the ionosphere using LOFAR observations of trans-ionospheric radio propagation from compact natural radio sources. This is advantageous as, unlike most artificial satellites, natural radio sources are inherently broadband emitters and LOFAR is a broadband receiver with high frequency and time resolution. The behaviour of radio scattering through the ionosphere can thus be observed simultaneously across many frequencies. 

Observations using the LOw Frequency ARray (LOFAR: van Haarlem et al., 2013) of trans-ionospheric radio propagation through a TID over the UK were made on 7 January 2019 (Figure 1). In LOFAR data, ionospheric variability manifests as rapid changes in the received signal from the radio source. Using this technique, internal sub-structure within the TID were clearly identified with dominant modes of oscillation on timescales of ~300s. At the observing geometries used these oscillations equated to sub-structure scale sizes of ~20 km. Contemporary GNSS and ionosonde data were used to provide the global parameters of the TID. At the observation frequencies used (25-65 MHz) the Fresnel scale is between 3-4 km; consequently the majority of the scattering features observed were lens-like refractions, rather than diffractive scintillation. Geomagnetic conditions at this time were very quiet, suggesting a terrestrial driver.


Figure 1: Left panels: LOFAR dynamic spectra from UK and Irish stations showing rapid variations in received signal power across the full observing band, caused by passage of TID internal substructure across raypath. Right panels: GNSS plasma anomaly maps from the observing period with the wave-like form of the TID clearly visible over the UK.

Original article for further details: 

Dorrian, G., Fallows, R., Wood, A., Themens, D. R., Boyde, B., Krankowski, A., et al. (2023). LOFAR observations of substructure within a travelling ionospheric disturbance at mid-latitude. Space Weather, 21, e2022SW003198. https://doi.org/10.1029/2022SW003198



van Haarlem, M. P., Wise, M. W., Gunst, A. W., Heald, G., McKean, J. P., Hessels, J. W. T., et al. (2013). LOFAR: Low-frequency-array. Astronomy and Astrophysics, 556, A2. https://doi.org/10.1051/0004-6361/201220873

Hines, C. O. (1960). Internal atmospheric gravity waves at ionospheric heights. Canadian Journal of Physics, 38(11), 1441– 1481. https://doi.org/10.1139/p60-150



Fine‐Scale Electric Fields and Joule Heating From Observations of the Aurora

By Patrik Krcelic (University of Southampton)

Optical measurements from three selected wavelengths have been combined with modelling of emissions from an auroral arc to estimate the magnitude and direction of small-scale electric fields on either side of an auroral arc for an event at 22:47:45 UT on 21 December 2014. The temporal resolution of the estimates is 0.1 s, which is much higher resolution thameasurements from Super Dual Auroral Radar Network (SuperDARN) in the same region, with which we compare our estimates. The obtained electric fields have peak value of 88 ± 16 mV/m on the northern side of the arc and peak value of 66 ± 21 mV/m on the southern side of the arc. Additionally, we have used the Scanning Doppler Imager instrument to measure the neutral wind during the event in order to calculate the height integrated Joule heating. Joule heating obtained from small scale electric fields gives much larger values than that obtained from SuperDARN data. Results are briefly shown in the movie below, where the top two panels depict an observed and modelled auroral arc analyzed in current syudy, and the bottom plot depicts the evolution of Joule heating in time on each side of the auroral arc compared with the SuperDARN estimate. Our optical method for estimating electric fields, and consequently the Joule heating using ASK, has proven to be very valuable in understanding the local heating effects in the vicinity of auroral activity. Such high spatial and temporal resolution electric fields may play an important role in the dynamics of the magnetosphere-ionosphere-thermosphere system.

Figure: The top left panel depicts observed auroral arc emission at 730 nm, while the top right panel depicts the same modelled auroral arc emission. Contours on the observed images represent the 95% level of the modeled brightness. The red vectors in the modeled images represent ion drift obtained from our modeling technique on each side of the auroral arc. Note that the vectors are not scaled and are here for illustrative purposes. Bottom panel depicts the evolution of Joule heating obtained from small scale electric fields. The red line represents Joule heating south of the auroral arc, the blue line represents Joule heating north of the auroral arc and the black line represents Joule heating obtained from SuperDARN measurements. Dashed lines represent standard deviations.

Original article for further detail: 

Krcelic, P., Fear, R. C., Whiter, D., Lanchester, B., Aruliah, A. L., Lester, M., & Paxton, L. (2023). Fine-scale electric fields and Joule heating from observations of the aurora. Journal of Geophysical Research: Space Physics, 128, e2022JA030628. https://doi.org/10.1029/2022JA030628 


Modeling the Time-Dependent Magnetic Fields That BepiColombo Will Use to Probe Down Into Mercury's Mantle

By Sophia Zomerdijk-Russell (Imperial College London)

The interior structure of a magnetised planet can be determined by using electromagnetic induction processes that results from solar-wind-driven magnetopause variability. To determine a profile of conductivity through depth within a planet, a broad spectrum of inducing fields is needed, as each discrete frequency will probe to a certain depth.

In preparation for the arrival of BepiColombo at Mercury in 2025, we have identified the opportunity to use Helios data to assess how solar wind ram pressure forcing can drive magnetopause variability at Mercury, as Helios took measurements during a similar phase of the Solar Cycle that BepiColombo is expected to see on its arrival. We find that Mercury’s magnetosphere is bombarded by a highly variable and unpredictable solar wind with a broad range of frequency signals and that the inducing field generated in response to the variable solar wind ram pressure is non-uniform across the planet’s surface.

A solar wind ram pressure time series from Helios measurements and the KT17 Hermean magnetospheric field model (Korth et al., 2017) were then used to generate a ram pressure driven inducing field spectra at two points on Mercury’s surface. In power spectra of these example inducing field spectra, frequency signals were found to peak between ~5.510-5 and 1.510-2 Hz. Heyner et al. (2021) determined that signals with these frequencies should penetrate into Mercury’s crust and mantle.

Particular orbital configurations of the BepiColombo mission will have MPO inside Mercury’s magnetosphere and Mio measuring the upstream solar wind, see Figure 1. Therefore, the dual spacecraft nature of the BepiColombo mission will be well suited to investigate Mercury’s magnetosphere’s response to external solar wind variability and allow a conductivity profile through to the mantle to be derived from observations of solar wind driven inducing field spectra with timescales seen in this work.

Figure 1. Schematic showing particular BepiColombo MPO (purple) and Mio (orange) spacecraft orbital configurations that will be useful for utilising electromagnetic sounding techniques at Mercury. An average location of the magnetopause is shown in green. Magnetopause variability inducing field signals on the order of a few minutes to a few hours will be able to penetrate through Mercury’s crust and into the mantle, shown by the blue shaded region.

Original article for further detail:

Zomerdijk-Russell, S., Masters, A., Korth, H., & Heyner, D. (2023). Modeling the time-dependent magnetic fields that BepiColombo will use to probe down into Mercury's mantle. Geophysical Research Letters, 50, e2022GL101607. https://doi.org/10.1029/2022GL101607


Heyner, D., Auster, H.-U., Fornaçon, K.-H., Carr, C., Richter, I., Mieth, J. Z. D., Kolhey, P., Exner, W., Motschmann, U., Baumjohann, W., Matsuoka, A., Magnes, W., Berghofer, G., Fischer, D., Plaschke, F., Nakamura, R., Narita, Y., Delva, M., Volwerk, M., … Glassmeier, K.-H. (2021). The BepiColombo Planetary Magnetometer MPO-MAG: What Can We Learn from the Hermean Magnetic Field? Space Science Reviews, 217(4), 52. https://doi.org/10.1007/s11214-021-00822-x

Korth, H., Johnson, C. L., Philpott, L., Tsyganenko, N. A., & Anderson, B. J. (2017). A Dynamic Model of Mercury’s Magnetospheric Magnetic Field. Geophysical Research Letters, 44(20), 10,147-10,154. https://doi.org/10.1002/2017GL074699


Variations in Observations of Geosynchronous Magnetopause and Last Closed Drift Shell Crossings With Magnetic Local Time

By Tom Daggitt (British Antarctic Survey, University of Cambridge)

Geostationary satellites may cross the magnetopause during highly active times when it can be compressed inside geostationary orbit. At this time the satellite will switch from observing Earth’s magnetic field to the interplanetary magnetic field, which is usually opposing Earth’s field during compressions. The satellite will observe a drop in electron flux as it goes from measuring trapped electrons in Earth’s radiation belts to electrons in the interplanetary medium.

We compare observations from the GOES-13 and GOES-15 satellites during geomagnetic storms. We attempt to predict magnetopause crossings using models of the last closed drift shell (LCDS), the outermost stable orbit for an electron trapped in Earth’s magnetic field. The LCDS is modelled as the largest L* value that calculated by the IRBEM magnetic field modelling library (Boscher et al., 2013), using a method derived from Albert et al. (2018).

Figure 1(A) shows the Bz component of the field measured by the GOES magnetometers, demonstrating independent magnetopause crossings when the Bz component is negative. Each satellite only sees a magnetopause crossing when it is nearer local noon.

1(B) shows the satellite L* and the LCDS derived from the TS05 field model (Tsyganenko & Sitnov, 2005). Neither satellite crosses the LCDS during their magnetopause crossings, showing that brief crossings cannot be predicted with this method.

1(C) shows the >0.8MeV flux measured by the GOES satellites, showing rapid decreases in the measured flux associated with each magnetopause crossing. GOES-13 also shows a large decrease in flux as it moves into the nightside, likely due to distortion in the magnetotail.

The difference in the observed flux profiles demonstrates that choice of satellite may have a large effect when using satellite data to drive radiation belt models. Data from multiple satellites should be used to ensure constant measurements of the trapped flux on the dayside when driving radiation belt models.


Figure 1: (A) GSM Bz component measured by GOES satellites. (B) GOES L* and LCDS location, both calculated with the TS05 field model. (C) GOES EPEAD >0.8MeV integral fluxes. (D) GOES magnetic local time. The darker shaded region shows when one or both satellites are on the nightside (6 < MLT < 18)


Boscher, D., Bourdarie, S., O’Brien, P., & Guild, T. (2013). Irbem library v4.3, 2004-2008. https://spacepy.github.io/irbempy.html.

Albert, J. M., Selesnick, R., Morley, S. K., Henderson, M. G., & Kellerman, A. (2018). Calculation of last closed drift shells for the 2013 gem radiation belt challenge events. Journal of Geophysical Research: Space Physics, 123(11), 9597– 9611. https://doi.org/10.1029/2018JA025991

Tsyganenko, N., & Sitnov, M. (2005). Modeling the dynamics of the inner magnetosphere during strong geomagnetic storms. Journal of Geophysical Research, 110(A3), A03208. https://doi.org/10.1029/2004JA010798


Associated Paper:

Daggitt, T. A., Horne, R. B., Glauert, S. A., Del Zanna, G., & Freeman, M. P. (2022). Variations in observations of geosynchronous magnetopause and last closed drift shell crossings with magnetic local time. Space Weather, 20, e2022SW003105. https://doi.org/10.1029/2022SW003105