"I have always been fascinated by complicated subjects"

Baptiste Frei, along with three other researchers, you received the 2024 EPS Plasma Physics Division PhD Research Award. What was your reaction when you heard the news?
I was both surprised and honored. Most importantly, this prize inspires me to continue contributing to the field of plasma fusion.

Can you explain the subject of your thesis "A gyrokinetic moment model of the plasma boundary in fusion devices"?
My PhD thesis addresses a crucial question in the fusion community: developing an efficient analytical and numerical framework to accurately model plasma turbulence in the outermost region of the plasma in magnetic fusion devices. Despite recent progress in fusion research (for instance, in plasma edge turbulence simulations by the theory group led by Prof. P. Ricci at SPC), significant improvements in physical models and numerical tools are still needed to bridge the gap between current modeling capabilities and making reliable predictions of edge turbulence for future large devices, such as ITER. In my PhD thesis, I developed a model that can describe plasma turbulence in the edge region using a multi-fidelity approach, allowing the accuracy of the plasma model to be adjusted based on the plasma conditions.

To optimize fusion gain in future power plants, it is essential to maximize edge pressure while maintaining good energy confinement

It's been said that the plasma edge is a crucial but little-understood region. Why?
To optimize fusion gain in future power plants, it is essential to maximize edge pressure while maintaining good energy confinement, ensuring sustainable heat exhaust from the core, and effectively managing turbulent transport in the edge region. This makes the edge region critical for designing and predicting the performance of future reactor devices. However, unlike the core region, which has been extensively studied for many decades with advanced numerical and analytical tools, the role of turbulence in the edge region is much less understood. This is due to the unique properties of the edge region, such as its complex magnetic geometry and large temperature gradients, which challenge the validity of existing modeling tools.

What concrete contribution does your work make to the research towards the first fusion reactor?
The main contribution of my work is the establishment of a new analytical and numerical framework that is valid across the entire edge region, addressing a limitation of previous models. This framework can efficiently predict turbulent transport in the edge region, allowing us to assess the overall performance of future fusion reactors at a reasonable computational cost. This advancement will deepen our understanding of plasma dynamics in the edge region and enhance our confidence in the development of the first fusion reactor.

What do you see as the greatest challenges still to be tackled in this direction?
There are still many open questions that need to be addressed for the implementation of the model proposed in my PhD thesis. I believe that one of the crucial aspects is the validation of this new model against existing experiments, particularly in realistic reactor-relevant conditions. However, given the importance of simulating turbulence in the edge region, I am confident that these challenges will be successfully overcome in the near future.

The teaching ability of Prof. Paolo Ricci to share his passion for fusion research rapidly convinced me to pursue a master thesis

Prof. Paolo Ricci supervised your thesis. What did he bring you?
Before I started my PhD thesis at SPC, I had Prof. Paolo Ricci as a lecturer for a master plasma course at EPFL. I was quickly intrigued by the complexity of plasma behavior and its mathematical description. The teaching ability of Prof. Paolo Ricci to share his passion for fusion research rapidly convinced me to pursue a master thesis and then a PhD in his group. Most importantly, I believe that his experience as a scientist and his availability to the PhD students in his group were crucial and provided me with great support.

Paolo Ricci says of you that you're a hard worker, that you see things through to the end with an immense thirst for knowledge. Where does this passion and determination come from?
I have always been fascinated by complicated subjects like plasma physics and have always been interested in technological and social challenges, such as fusion energy. Therefore, I believe that this unique combination of interests in plasma physics has motivated me to give my best in my research.

You did almost all your studies at EPFL and then the Swiss Plasma Center (SPC), from bachelor's to doctorate. What did this environment bring you?The EPFL campus is a unique place where students can enjoy the lake and mountains while being in close proximity to some of the most influential research groups in the world, such as the SPC. This environment provided a perfect balance during my studies at EPFL, which I deeply appreciate. I always enjoyed returning to Lausanne to visit my family and friends.

One of my best memories at SPC is the Fondue night

Can you share with us one of your best memories at SPC?
SPC is established as one of the most important fusion research centers in the world, but it is also known for its unique and international atmosphere among PhD students, PostDocs, and permanent scientists. For instance, one of my best memories at SPC is the Fondue night, where Swiss PhD students organize a cheese fondue for other PhDs and PostDocs every year.