Inter- and Transdisciplinary Sessions
Disciplinary sessions AS–GM
Disciplinary sessions GMPV–TS

Session programme


ST – Solar-Terrestrial Sciences

Programme group chair: Olga Malandraki

ST1 – Sun and Heliosphere

Programme group scientific officers: Manuela Temmer, Olga Malandraki


This session traditionally provides a forum for the discussion of all aspects of solar and heliospheric physics. Popular topics have included solar cycle dependencies of the Sun, solar wind and heliosphere, Coronal Mass Ejection research, studies of energetic particles throughout the heliosphere, and the outer boundaries of the heliosphere. We encourage contributions related to all ongoing and planned space missions, to ground-based experiments and to theoretical research. Papers presenting ideas for future space missions and experiments are very welcome in this session. The session will consist of both oral and poster presentations.

Convener: Manuela Temmer | Co-conveners: André Galli, Olga Malandraki, Pietro Zucca, Jasmina Magdalenic
| Attendance Fri, 08 May, 14:00–15:45 (CEST), Attendance Fri, 08 May, 16:15–18:00 (CEST)

Much of our knowledge about the large-scale structure and variations of
the solar wind, interplanetary magnetic field (IMF), transients (coronal
mass ejections, shocks) and energetic particles in the inner heliosphere
(< 2 AU) was gained from multi-spacecraft in-situ measurements,
especially from missions such as Helios and STEREO as well as
conjunctions between spacecraft at various planets. We have also gained
some knowledge of structures and variability in the interplanetary space
associated with turbulence, waves and instabilities on much smaller
scales thanks to ACE, Wind and ARTEMIS as well as MMS, while their
properties on intermediate (meso) scales is yet mostly unknown. The aim
of this session is to discuss progress in our understanding of CMEs,
CIRs, shocks, SEPs, the IMF and solar wind made thanks to
multi-spacecraft measurements on various scales ranging from a fraction
of an earth radius to 1 AU and the way forward. This session invites
abstracts related to analyses and simulations of multi-spacecraft
measurements in the inner heliosphere. It is especially interested in
in-situ measurements made possible by STEREO (which will be within 60
degrees of the Sun-Earth line by the end of 2020), Solar Probe, Solar
Orbiter and missions near L1, planetary missions (MESSENGER,
BepiColombo, MAVEN) as well as future missions, concepts and
instrumentation to investigate the various scales in interplanetary

Convener: Harald Kucharek | Co-conveners: Charles Farrugia, Benoit Lavraud, Noé Lugaz, Alessandro Retinò
| Attendance Mon, 04 May, 16:15–18:00 (CEST)

The Sun’s corona is the birthplace of the solar wind, coronal mass ejections, associated shock waves and solar energetic particles which all are fundamental drivers of space weather. The key physical processes at the origin of these phenomena, i.e. the heating and acceleration of the coronal plasma and energetic particles, have not been clarified to date. By EGU 2020 Parker Solar Probe (PSP) will have completed the fourth of its 24 scheduled orbits around the Sun. The first three orbits have the same perihelia of 35.6 solar radii, while it will move as close as 27.8 solar radii to the Sun during the fourth and fifth orbits. PSP is providing a treasure trove worth of in-situ and remote sensing data. The data from the first two orbits, that become public on November 12, 2019, have already revealed phenomena never seen before. Solar Orbiter (SO) is scheduled to launch in February 2020. The in-situ instruments will become fully operational by May 2020. The remote sensing instruments will be switched on later. Combining the PSP observations with data from SO, with remote sensing observations from SDO, STEREO and Proba2, with other in-situ data, e.g., from ACE and DSCOVR, with ground-based observations and with theoretical models will be a challenging and exciting task. This session invites oral and poster contributions on all aspects of research addressed to the exploration of our near-Sun environment, with special focus on the new observations from PSP and topics related to the latest status of the SO mission.

Convener: Volker Bothmer | Co-conveners: Olga Malandraki, Nour E. Raouafi, Alexis Rouillard, Marco Velli
| Attendance Thu, 07 May, 14:00–15:45 (CEST)

With discoveries of the past (e.g., Mariner, Pioneers, Ulysses) and the present (e.g., Voyager, SOHO/SWAN, IBEX, New Horizons) heliospheric missions, the exploration of the heliosphere, its boundary regions, the outer reaches of our solar system, as well as the Very Local Interstellar Medium (VLISM) has profoundly changed the view of our space in the universe. The Interstellar Mapping and Acceleration Probe (IMAP) is a future space mission dedicated to study the interaction of the solar wind with the interstellar medium and the acceleration of energetic particles. These two topics are crucial for understanding the coupling between the inner and the outer heliosphere. The Interstellar Probe escaping beyond the solar-system boundaries with new measurements would be crucial to enable the new understanding and discoveries of the global heliosphere, the interstellar medium, the Kuiper Belt, the circumsolar dust disk, and the evolution of our solar system. This session focuses on advancing the understanding of the heliosphere and its interaction with VLISM as well as the groundbreaking science of interstellar exploration, instrumentation for relevant in-situ and remote measurements, and the relevant mission and spacecraft concepts.

Convener: Justyna M. SokolECSECS | Co-conveners: André Galli, Olga KatushkinaECSECS, Linghua Wang, George Ho, Robert F. Wimmer-Schweingruber
| Attendance Wed, 06 May, 08:30–10:15 (CEST)

Current sheets and magnetic islands observed in the solar wind play a significant role in local particle acceleration to keV-MeV energies, and the resulting energetic particle enhancements constitute a potentially hazardous condition in the interplanetary and near-Earth space. Current sheets of various scales are self-organized structures that are formed ubiquitously in cosmic and laboratory plasmas owing to a change in the magnetic field direction, at strong discontinuities, and as a result of turbulence. Not surprisingly, dynamic processes occurring at current sheets and in their vicinity have a striking similarity in different plasmas. Current sheets experience magnetic reconnection that in turn leads to many subsequent nonlinear effects, triggering the development of a turbulent cascade, the formation of magnetic islands or flux ropes, and local acceleration of charged particles. These processes are observed from the corona to the outer heliosphere and may often be described by the same equations. They also can be linked physically as some of the structures originating from the corona survive and evolve further in the solar wind. These processes have been studied by different scientific teams in independent ways, but currently there is a tendency to analyze them employing a unified approach.
This interdisciplinary session will bring together specialists from different plasma physics communities, bridging gaps in the understanding of the origin of coherent structures and the development of dynamical processes associated with current sheets. We invite researchers to share recent results of their theoretical studies, modelling and observations. Contributions that discuss and compare different mechanisms of local particle energization that occur in laboratory plasmas, the solar corona, magnetospheres of planets and the heliosphere are especially welcome.

Public information:
Welcome to session ST1.7!
If you are interested in solar or space physics, especially, if you want to know more about processes related to current sheets and/or plasmoids/blobs/magnetic islands/flux ropes of various sizes and origins, you are in the right place at the right time!
Here you can find how dynamics of these structures impact magnetic reconnection, turbulence and particle acceleration from the solar corona to the outer heliosphere, and why these complex phenomena represent an important piece of the space weather puzzle.
Do not hesitate to ask questions, using the online chat opportunity below. Not all questions can be answered so far, but you will certainly get an exciting discussion. :-)

Please note that we organize a related Zoom conference on Wednesday, 2020 May 6, therefore there is an opportunity to communicate with some authors directly before or after the official EGU chat time. The program of the virtual meeting and the corresponding Zoom conference link can be found here:
https://drive.google.com/open?id=1k2uHDQnWPIHES3hXfKiy8VEYYFfyhM-8 (please copy the link to your browser to open it) .
You are welcome to attend!

Best regards,
Conveners of session ST1.7

Convener: Olga Khabarova | Co-conveners: Spiro Antiochos, Jakobus le Roux, Olga Malandraki
| Attendance Wed, 06 May, 14:00–15:45 (CEST)

The solar wind is an uninterrupted flow of highly ionised plasma that fills interplanetary space and is crossed by strong transient perturbations such as coronal mass ejections (CMEs), (corotating) stream interaction regions (SIRs), and solar energetic particles (SEPs). These phenomena are capable of driving large disturbances at Earth as well as at the other planets. Remote-sensing observations from multiple vantage points, in-situ measurements from multiple well-separated locations, and novel modelling efforts have been employed systematically to study the properties of the solar wind plasma and of solar transients in general, from their formation to their arrival at different planets throughout the inner heliosphere. However, despite the number of past and current spacecraft missions distributed throughout the heliosphere, it is still difficult to fully understand the properties of these transients phenomena, including their 3D structure and their evolution with heliocentric distance.

The recently launched Parker Solar Probe, the imminent launch of Solar Orbiter, current and planned planetary missions, as well as potential future missions at L1, L5, and over the solar poles, will provide us with the perfect opportunity to test, validate, and refine the current knowledge of these physical phenomena and their interactions at different heliocentric distances. Accordingly, the aim of this session is to showcase the latest observational and modelling efforts regarding the evolution of the solar wind and solar transients during their propagation throughout the heliosphere as seen from multiple vantage points, and to foresee future developments. Potential improvements to our current space weather forecasting capabilities will be highlighted.

Convener: Rui Pinto | Co-conveners: David BarnesECSECS, Erika PalmerioECSECS
| Attendance Wed, 06 May, 10:45–12:30 (CEST)

The “Theory and Simulation of Solar System Plasmas” session solicits presentations of the latest results from theoretical investigations and numerical simulations in space plasma-physics from microscopic to global scales, in comparison with experiments and observations in the heliosphere: at the Sun, in the solar corona, in interplanetary space and in planetary magnetospheres. Each year a topic of special interest is chosen as a focus of the session. For 2020 this focus will be on space plasma turbulence and its consequences for particle acceleration and plasma heating. There are challenging questions in fundamental solar system plasma physics which require the analyses of huge amounts of data, in particular of the particle kinetics. Machine learning techniques have to be used. We further encourage presentations of theory and simulation results relevant for to current, forthcoming and proposed space missions, notably MMS, Parker Solar Probe, Bepi Colombo and Solar Orbiter.

Convener: Jörg Büchner | Co-conveners: Philippa Browning, Giovanni Lapenta, Shangbin Yang
| Attendance Wed, 06 May, 16:15–18:00 (CEST)

The session solicits contributions that report on nonthermal solar and planetary radio emissions. Coordinated multi-point observations from ground radio telescopes (e.g., LOFAR, LOIS, LWA1, URAN-2, UTR-2) and spacecraft plasma/wave experiments (e.g., Cassini, Cluster, Demeter, Galileo, Juno, Stereo, Ulysses and Wind) are especially encouraged. Presentations should focus on radiophysics techniques used and developed to investigate the remote magnetic field and the electron density in solar system regions, like the solar corona, the interplanetary medium and the magnetized auroral regions. Interest also extends to laboratory and experimental studies devoted to the comprehension of the generation mechanisms (e.g., cyclotron maser instability) and the acceleration processes (e.g., Alfven waves). Further preparations, evaluations, investigations, analyses of forthcoming space missions (like BepiColombo, Juice, Solar Orbiter, Solar Probe, SunRISE, Taranis) are also welcome.

Co-organized by ST1
Convener: Patrick Galopeau | Co-convener: Mohammed Y. Boudjada
| Attendance Tue, 05 May, 16:15–18:00 (CEST)

The Open Session on Moon, Mars, Mercury, Venus as terrestrial planets systems aims at presenting highlights of relevant recent results through observations, modelling, laboratory and theory. Key research questions concerning the surface, subsurface, interior and their evolution will be discussed, as well as instruments and techniques from Earth and space.

Co-organized by GD11/GI6/ST1
Convener: Joe Zender | Co-conveners: Johannes Benkhoff, Alireza HosseiniaraniECSECS, Joana S. Oliveira, Francesca Zambon
| Attendance Tue, 05 May, 08:30–10:15 (CEST)

Turbulence, reconnection and shocks are fundamental non-linear processes observed in solar, heliospheric, magnetospheric and laboratory plasmas. These processes are not separate, but rather appear to be interconnected. For instance, a close link exists between reconnection and turbulence. On the one hand the turbulence cascade favors the onset of magnetic reconnection between magnetic islands and, on the other hand, magnetic reconnection is able to trigger turbulence in the reconnection outflows and separatrices. Similarly, shocks may form in collisional and collisionless reconnection processes and can be responsible for turbulence formation, as for instance in the turbulent magnetosheath.

This session welcomes simulations, observational and theoretical works relevant for the study of these non-linear phenomena. Particularly welcome will be works focusing on the link between them in a range of scale going from fluid MHD to kinetic. This year we encourage especially papers proposing new methods, especially those rooted in Artificial Intelligence (AI) and Machine Learning (ML), to extract new knowledge from big observational and simulated data sets.

Public information:
please check EGU chat for new zoom link and password

Co-organized by ST1
Convener: Maria Elena Innocenti | Co-conveners: Francesco Pucci, Meng Zhou, Giovanni Lapenta, Luca Sorriso-Valvo
| Attendance Wed, 06 May, 16:15–18:00 (CEST)