MIST

Magnetosphere, Ionosphere and Solar-Terrestrial

Latest news

2019 Rishbeth prize winners announced

We are pleased to announce that the Rishbeth Prizes this year are awarded to Affelia Wibisono and Michaela Mooney , both of the Mullard Space Science Laboratory (UCL).
 
Affelia Wibisono wins the prize for the best MIST student talk, entitled “Jupiter’s X-ray Aurorae as seen by XMM-Newton concurrently with Juno”. Michaela wins the best MIST poster prize, for a poster entitled “Evaluating auroral forecasts against satellite observations”.
 
MIST Council would like to congratulate both Affelia and Michaela. As prize winners, Affelia and Michaela have been invited to write articles for Astronomy & Geophysics, which we look forward to reading.

Call for MIST/GEM Liaisons

There is a potential opening for a member of the MIST community to act as a liaison with the GEM (Geospace Environment Modelling) group. This will be an opportunity to act as a representative of the UK MIST community and inform GEM about relevant activities within the MIST community.

GEM liaisons will typically have the following responsibilities:

  1. Attend​​ a preponderance ​​of ​​GEM Steering ​​Committee ​​meetings​ ​at ​​summer​ ​workshop and​ ​mini-GEM​ ​​(June​ ​and​ ​December)
  2. Provide​​ written​​ annual​​ report​​ to​​ GEM Communications ​​Coordinator​​​ (by ​​April)
  3. Help ​​recruit ​​new​ ​GEM Steering​ ​Committee ​​members ​​​(as ​​needed)
  4. Provide ​​feedback​​ from​​ the​​ MIST community ​​and​​ share​​ with the GEM Chair/Vice​ ​Chair​ ​​(ongoing)

At this stage we would like to welcome any expressions of interest for this role from the community. If you are interested in being a GEM Liaison, then please This email address is being protected from spambots. You need JavaScript enabled to view it. including up to 100 words detailing why you would like to be a liaison and how your experience equips you for this role, and how often you would be able to attend GEM meetings.

If you have any further questions or would like more information about what the role would entail then please get in touch!

ESA Voyager 2050

As was touched upon at the business lunch at NAM, ESA has launched the next in its series of milestones to shape long-term scientific planning, which is called Voyager 2050.
 
The next milestone in this process is a call for white papers, and this is outlined in detail here. In short, 20 page proposals are invited describing clear science questions and explaining how a space mission would address those questions. The deadline is 5 August 2019.
 
MIST Council hopes that members of the MIST community are planning to submit white papers to this call, and we would be very interested to hear from those who are planning to do this, or those who have already applied to be part of the Topical Teams also outlined in the call.

MIST Council election results

Following a call for nominations, Greg Hunt (Imperial College London) and Maria-Theresia Walach (Lancaster University) have been elected unopposed to MIST Council. We congratulate the two new MIST councillors!

We would also like to express our thanks and appreciation to both Ian McCrea and Sarah Badman who are leaving MIST Council, for their invaluable contributions and commitment to the MIST community.

UK Space Agency call for nominations for the position of Chair of the Science Programme Advisory Committee

The UK Space Agency (UKSA) is seeking a new Chair for the Science Programme Advisory Committee (SPAC). The position of Chair of the Science Programme Advisory Committee will become vacant on 1 July 2019.

The UK Space Agency welcomes applications from the UK space science community. The full position and person specifications are on the Government's website.

 

Statistical Planetary Period Oscillation Signatures in Saturn's UV Auroral Intensity

by Alexander Bader, Lancaster University, UK.

Saturn's highly dynamic auroras are generated by electrons precipitating along the magnetic field lines into the planet's polar ionospheres due to currents along the magnetic field lines. Therefore, the aurora provide information about the location and strength of these field-aligned currents. Two types of large-scale current systems have been observed in magnetic field measurements: one a quasi-static system associated with flow shears between plasma rotating at different speeds in the outer magnetosphere. The other significant type are field-aligned current systems rotating according to the planetary period oscillation (PPO) systems. Both the northern and the southern hemisphere are associated with one such system each, superimposed on the quasistatic system and causing roughly 10.7-hour periodic oscillations throughout the Kronian magnetosphere.

Upward and downward field-aligned currents in the northern ionosphere were found to be modulated by rotating patterns imposed by both the northern and southern PPO systems, the latter modulation being facilitated through interhemispheric current closure. The auroral intensity is hence also expected to be modulated accordingly, such that the northern aurora is brightest at roughly ΨN/S = 90°, where the currents have also been shown to maximize. Due to the two PPO systems rotating at slightly different angular velocities, this results in a double modulation.

In this study we analyzed the statistical behavior of Saturn's ultraviolet auroral emissions over the full Cassini mission using all suitable Cassini-UVIS images acquired between 2007 and 2017. This study shows for the first time that both hemispheres' auroral intensities are modulated by both the PPO system associated with the same hemisphere (primary system, Fig. 1a) and the opposite hemisphere (secondary system, Fig. 1b), relatively. The modulation by the primary system is found to be more intense than the one caused by the secondary system. This confirms that both PPO systems' field-aligned currents traverse the entire magnetosphere and close at least partly in the hemisphere opposite to where the generating perturbation is located.

For more information, see our paper below:

Bader, A., Badman, S. V., Kinrade, J., Cowley, S. W. H., Provan, G., & Pryor, W. R. (2018). Statistical planetary period oscillation signatures in Saturn's UV auroral intensity. Journal of Geophysical Research: Space Physics, 123, 8459–8472. https://doi.org/10.1029/2018JA025855

Figure 1: Average northern UV auroral intensity maxima per local time (4/3 h bin size) and PPO phase ΨN/S (20° bin size), shown in a logarithmic color scale. (a) Northern hemisphere auroral intensity ordered by the northern PPO system and (b) northern hemisphere auroral intensity ordered by the southern PPO system. Two Ψ phase cycles are plotted for clarity, the expected locations of maximum upward current are indicated by dashed white lines. On the top and to the side of each 2D histogram the averages of the mean intensity maxima over the ΨN/S and LT dimensions are shown in black, respectively. Separate histograms showing the PPO intensity modulation in the dawn-noon (blue) and dusk-midnight (red) regions are calculated from the parts of the histogram marked with colored boxes and shown to the right side (note the logarithmic intensity scale). The histogram over the full LT range (black) has been fitted with a simple sine (gray). Its maxima are marked with vertical dash-dotted lines, its peak-to-peak (pk-pk) amplitude and the ΨN angle with the highest intensity are given in the top right corner of each panel.