Johannes Geiss Fellowship

Sandra Chapman is the Johannes Geiss Fellow 2023 and is a plasma physicist working on problems in astrophysics and in the laboratory. She is currently Professor of Physics and Director of the Centre for Fusion, Space and Astrophysics at the University of Warwick and adjunct Professor at UIT. Her early work on nonlinear plasmas was recognised with the COSPAR Zeldovich Medal (commission D) and the EGS Young Scientists’ Medal. She was selected to give the 2014 Royal Astronomical Society James Dungey Lecture and the 2020 Ed Lorenz Lecture at the Fall meeting of the American Geophysical Union. Sandra is part of a team awarded a 2021 Lloyd’s of London Science of Risk Prize. She has been awarded the 2022 Royal Astronomical Society Chapman Medal and the 2024 Johannes Alfvén Medal of the European Geosciences Union. In the following paragraphs she answers a few questions – asked by Roland Hohensinn, ISSI Post Doc – about her research. Roland Hohensinn is postdoctoral fellow in Earth Sciences and Data scientist. He does research on uncertainty quantification from satellite remote sensing data, with a focus on space geodetic techniques (GRACE/GRACE-FO terrestrial water storage, long-term GPS ground motions).

Roland Hohensinn: Sandra, please explain us the beauty of your science.

Sandra Chapman: I have been privileged to be able to work across a variety of topics under the general heading of ‘plasma physics’. Plasmas are not only ubiquitous in the universe, they are also fundamentally non-linear and, in space and astrophysical systems particularly, are far from equilibrium. So our study of plasma physics touches upon some of the deepest physics questions- how does entropy increase in a collisionless plasma? How do we go from physics which on the microscale is reversible, but on the macroscale, irreversible, without collisional dissipation? How are particles accelerated, how do energy and momentum flow between fields and particles?

The models and mind-pictures that we use are based on the equations of Maxwell, Lorentz, Liouville et al, and these are fundamentally beautiful in their structure and expression. I am a great fan of ‘the truth is usually beautiful’ approach to physics.

Roland Hohensinn: Which transformations you see your field undergoing at the moment?

Sandra Chapman: Thinking about space plasma physics, I think this is a particularly exciting, and challenging time. When I was beginning my physics career, the norm was to have access to the data from a single satellite and to look in detail at single time-series, perhaps to try some conjugate study with ground based observations or a second satellite. Plasma simulations were highly restricted in dimension and could only capture one physical scale of interest. Now we are in a data-rich era with imaging, multiple satellites and hundreds of ground based observations, all at unprecedented spatial and temporal resolution, but these observations are not homogeneous. Alongside this, we now have the capability to build and run computer simulations which evolve the fully non-linear plasma physics across multiple physical space and timescales. We need to think of new ways to extract, visualize, interrogate and compare the relevant information from this data, both from observations and simulations. There are many new tools for this that are well-established in other fields:  networks, machine learning, AI, but the critical first step in this process is in formulating the physics questions to be asked of the data and building this into the analysis pathway, otherwise it is ‘garbage in, garbage out’. I don’t think that human physicists will be out of a job anytime soon!

Roland Hohensinn: How do you see the current and future role of ISSI in space sciences?

Sandra Chapman: It is one of life’s ironies that the more a science career progresses, the less time there is available to actually do science. So institutes like ISSI are an invaluable refuge that combine time to think, with opportunities to discuss. Physics has no borders and space science in particular is intrinsically international. ISSI in particular offers the flexibility to co-ordinate international teams on new topics. The ways in which we communicate our science, to each other, and to the wider public, are also changing rapidly and ISSI I think is well positioned to play a key role in this.

The Johannes Geiss Fellowship (JGF) is established to attract to ISSI – for limited duration visits – international scientists of stature, who can make demonstrable contributions to the ISSI mission and increase ISSI’s stature by their presence and by doing so will honor Johannes Geiss for his founding of ISSI and his contributions to ISSI, and for his many contributions to a broad range of space science disciplines.

The International Space Science Institute (ISSI) in Bern, Switzerland invites applications for the Johannes Geiss Fellowship (JGF). With this fellowship ISSI honors the memory of Johannes Geiss, the founder of ISSI, and his contributions to the space sciences.

The fellowship was established in 2015 to attract internationally renowned scientists to make a demonstrable contribution to the ISSI mission by pursuing ambitious independent research, in any of the disciplines that are part of ISSI’s core mission: astronomy & astrophysics, astrobiology, plasma physics, solar physics, solar system science, Earth sciences from space.

The Johannes Geiss Fellow is expected to participate in ISSI activities and to collaborate with ISSI’s scientific staff and visitors, as well as with research institutes in Switzerland and neighboring countries. The Johannes Geiss Fellow is invited to give public lectures in close collaboration with the Pro ISSI Association.

The JGF provides a stipend covering travel costs and living expenses for a stay at ISSI in Bern of up to 6 months. ISSI can host fellows either for a single extended visit (e.g., during a sabbatical) or for several shorter duration stays.

Complete Call Johannes Geiss Fellowship 2024 (pdf) >>

All applications must be received by ISSI no later than October 3, 2023.

Online Submission Form >>

Marco Velli is the Johannes Geiss Fellow 2022 and Professor of Space Physics at the Earth, Planetary and Space Sciences Department, University of California, Los Angeles, USA. A student of the University of Pisa and Scuola Normale Superiore, he has spent research periods at the University of St. Andrews, Scotland, the Observatoire de Paris, France, Università della Calabria, Italy, and the Smithsonian CfA, Cambridge, MA, as well as the Jet Propulsion Laboratory, California Institute of Technology, where he remains a Senior Scientist. In the following paragraphs he answers a few questions – asked by Christian Malacaria, ISSI Post Doc – about his scientific work. Christian Malacaria is an X-ray astronomer with expertise in observations and data analysis of compact objects. He is a member of several X-ray missions such as Fermi/GBM, NICER and IXPE.

Christian Malacaria: What is the main advantage of being a Johannes Geiss Fellow at the International Space Science Institute?

Marco Velli: As a UCLA professor, I have several different official tasks and duties in addition to research, such as administrative, managerial and teaching. All these are an essential part of each scientist’s work but can become so cumbersome that eventually one is left with less and less time for the creative research process, or even just for enjoying in depth scientific discussions with colleagues and friends. The Johannes Geiss Fellowship (JGF) provides time away from the day-to-day hassle, allowing one to rediscover and enjoy pure research.

Being a JGF at ISSI offers numerous advantages, creating a highly favorable research environment. ISSI is a tranquil yet stimulating place, frequently visited by exceptionally interesting guests and featuring a vibrant atmosphere. Here, diverse scientists, both young and senior, from various backgrounds continuously come and go, providing opportunities for diverse brainstorming, which fosters innovative research projects. The peaceful environment and minimal mundane duties of ISSI allow me to feel comfortable and remain focused, free from distractions. Furthermore, ISSI provides a convenient apartment within a short walk of the institute, unlike my usual residence in Los Angeles, where I endure a one-hour traffic jam to get anywhere. In essence, as a JGF, the hassles of everyday life have been removed, making life at ISSI significantly easier. Moreover, at ISSI, I have been able to join several science teams and workshops, and even participate in meetings without being a formal team member. This opportunity is not available anywhere else in the world of space physics. Although my six-month Fellowship is coming to an end soon, I would reapply for the JGF experience right now. This experience has rekindled my enthusiasm for research, in ways that are impossible to replicate elsewhere.

Christian Malacaria: What are the most important open questions in Heliophysics and how are they going to be addressed?

Marco Velli: One of the most significant and fundamental problem is the existence of the heliosphere itself, closely linked with other essential questions such as: why does the Sun have a functioning dynamo and magnetic field? How is the solar corona heated and the solar wind generated? How are solar flares and coronal mass ejections triggered and solar energetic particles accelerated? Unfortunately, even with years of research, we still lack a comprehensive model that effectively addresses these questions.

The main obstacles to answering these questions can be divided into two categories: the first is related to observations, the second to time-scales: to start from the second point, our knowledge of the basic mechanisms behind the solar dynamo is limited by the Solar cycle periodicity: we must base our statistics onthe 11-year (22-year full) cycle, and though we have some observational proxies dating back centuries, routine mesaurements of the solar magnetic field from Earth is limited to  about 10 cycles, while direct measurements of the solar wind and of the x-ray corona date to the space age (< 5 cycles), with the highest resolution measurements from SDO being only about a decade old.

In addition, understanding the dynamo requires precise measurements of the magnetic fields and photospheric flows all the way to the solar poles, while we are limited from the ecliptic plane to measurements around 60 degrees. Such observations would be key in understanding the solar magnetic field, and indeed the ongoing joint ESA-NASA mission Solar Orbiter will move out of the ecliptic plane within the next few years hopefully providing major new discoveries over the coming decade. Complementary to that, NASA’s Parker Solar Probe is probing the solar corona directly and will be moving to a perihelion inside 10 solar radii from center within the next two years. The direct measurement of the solar wind and its magnetic field in this acceleration region by PSP is already revolutionizing our understanding of the solar corona and promises, in conjunction with Orbiter, a complete paradigm change within the decade.

A predictive theory based on solid observations of the solar dynamo, solar coronal heating and solar wind acceleration is fundamental to understand the dynamics of magnetized plasmas well beyond Solar or Stellar physics, from the interstellar medium to galactic halos, pulsar wind nebulae and black hole magnetospheres, active galactic nuclei and the hot intra-cluster medium. Solar flares and coronal mass ejections are at the lower end of energetic bursty phenomena associated with magnetized plasmas throughout the universe that are associated with the generation and acceleration of cosmic rays and the X-ray and gamma-ray universe more generally.

To progress in our understanding of the Heliosphere, key future missions should include a global constellation of observatories comprehensive of in ecliptic and out of ecliptic (polar) observations, allowing for a 3D reconstruction of the Heliosphere in its complexity and variability. Such a mission is of fundamental interest also in the context of space weather and of providing the plasma context and advance warning for future human exploration of the solar system.

Christian Malacaria: Given the importance of the social melting pot promoted by ISSI, what do you think is the role of science (and scientists) in society?

Marco Velli: Science is experiencing an unprecedented pace of breakthroughs across multiple domains, and the approach to scientific research is also undergoing a significant transformation. Large collaborative teams are replacing the traditional romanticized notion of the lone scientist working at their table. However, the amount of time devoted to science and critical thinking has not improved, and science classes in schools remain limited. This is concerning, as it may lead to generations of scientists with exceptional technical skills, but a limited understanding of the big picture.

The problem of “compartmentalized knowledge” can hinder scientific progress and our understanding of physics in several ways, including the limitations of our science, or the boundaries of our understanding. To prevent this, we need to apply scientific thought and critical reasoning to different environments, including everyday life. This would enable us to greatly expand the way science is practiced, and foster a more continuous form of education as opposed to the current discrete model.

Science no longer requires all-knowing gurus, as it did in the past. As science evolves, the role of “universalists” is fading, and team-based work is becoming the key to achieving groundbreaking goals. Each scientist is now part of a larger chain, and their responsibility is not solely to the advancement of science but also to a necessary knowledge of the limitations of the results and methodologies. This becomes even more paramount with the emergence of machine learning and artificial intelligence methodologies where understanding how a certain result has been obtained can become as difficult as the original question probed.

This also affects human interactions, where we must work together towards a common objective and contribute actively with critical thinking, rather than passively expecting higher organizations to take care of collective challenges. As scientists, we have a responsibility to help standardize this behavior and incorporate it as an ethical requirement. Given the privilege we hold as highly educated people, it is our duty to lead by example and promote a culture of collaborative work and continuous learning.

The Johannes Geiss Fellowship (JGF) is established to attract to ISSI – for limited duration visits – international scientists of stature, who can make demonstrable contributions to the ISSI mission and increase ISSI’s stature by their presence and by doing so will honor Johannes Geiss for his founding of ISSI and his contributions to ISSI, and for his many contributions to a broad range of space science disciplines.

Prof. Weiqing Han, University of Colorado at Boulder, USA and Prof. Sabine Schindler, University of Innsbruck, Austria have been elected as the 2020 Johannes Geiss Fellows. Prof. Weiqing Han is a world-renowned oceanographer who specializes in Global Sea Level Change, in particular, in coastal regions. Prof. Sabine Schindler is a highly recognized astrophysicist who specializes in the observation and modeling of galaxies and galaxy clusters. We have tele-interviewed both, asking a few questions about their upcoming fellowships at ISSI.

Prof. Han, Prof. Schindler, first of all, congratulations on your election as the Johannes Geiss Fellows 2020! What was your motivation to apply for the Johannes Geiss Fellowship at the International Space Science Institute? And have you already made plans when you will visit ISSI?

Weiqing Han:  The ISSI has been doing and leading active research in global and regional sea level variability and change, which fits my research interest and has been one of my major research focuses in the past decade. The motivation of my application is to establish collaboration with ISSI, and hope that by combining our effort and working in a simulating environment we can more effectively achieve our research goal.

Sabine Schindler: The International Space Science Institute is well known in the community – and well known to
me – as an excellent place for networking and communication in space science. To spend my sabbatical there with a Johannes Geiss Fellowship seemed ideal to me to expand the connections  to the space science community and to the Swiss universities. I am very happy, that this Fellowship was awarded to me and I am looking forward to my stay in Bern. I plan to start my visit in November.

Could you describe your scientific project(s) on which you plan to work during your visit to ISSI?

Weiqing Han: Rapid sea level rise is one of the most consequential impacts of the warming climate, exerting threats to human society in low-lying coastal areas and island nations. The observed rates of sea level change in the past few decades and century, however, have large spatial differences due to a complex mix of natural and anthropogenic factors. During my proposed visits to ISSI, I plan to investigate the effects of continental shelf and slope on coastal sea level signals that originate from open ocean. This area of research is important, because coastal bathymetry plays a crucial role in accurately depicting open-ocean impact on coastal sea level during historic periods and for future projections. Yet, this information is extremely limited due to the lack of high-resolution, basin-scale datasets and model experiments that can adequately resolve continental shelf and slope.

Firstly, we will analyze tide gauge observations, gridded satellite altimetry data, coastal altimetry data, together with reconstructed and reanalysis sea level products, to understand in which coastal areas a large amount of interior ocean signals can arrive at and be trapped to the coasts. While tide gauges are right on the coasts, altimeter data are contaminated by lands near the coasts. Therefore, the location of altimeter data may be a few tends of kilometers offshore from the tide gauge location. Secondly, we will  analyze large ensemble (LE) and CMIP6 climate model historic simulations, comparing the relatively coarse resolution model results with those of finer resolution ones, which can better represent continental shelf and slope.

Sabine Schindler: I plan to work on extragalactic astrophysics. I have a special interest in galaxies and galaxy clusters for two reasons:Firstly, for the physical processes and interactions that determine their evolution and secondly, for their cosmological applications. I plan to do observations as well as numerical simulations to do study these topics. I furthermore intend to do some interdisciplinary research, if something interesting is coming up in my discussions with the colleagues. I will keep my eyes open in this respect.

Prof. Schindler, is there a particular galaxy (or galaxies) you plan to focus on? And if so, why this particular one?

Sabine Schindler: I usually focus on processes, like e.g. ram-pressure stripping in galaxies or metal enrichment in galaxy clusters. I then select my targets according to the best suitability for a particular question.

Have you been to Switzerland and what – in addition to ISSI – makes Bern appealing to you for a visit?

Weiqing Han: In 2015 and 2018, I was invited to attend the sea level workshops organized and hosted by ISSI, Dr. Anny Cazenave from ISSI and Dr. Detlef Stammer from the U. of Hamburg, which aimed to tackle important but challenging issues toward understanding and projecting global (2015 meeting) and coastal (2018 meeting) sea level changes. On my side, the outcomes of the two meetings are that I led two review articles that were published in Surveys in Geophysics, one for climate modes’ impacts on spatially uneven sea level changes in the world’s oceans (published in 2017) and the other, focuses on impacts on coastal ocean (published in 2019).

Sabine Schindler: I have been to Switzerland before, both for work and for pleasure. I have enjoyed both. There is a very interesting astrophysical community in Switzerland, that I plan to visit. I have also been to Bern before, which I liked very much as a city.