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An extra set of eyes on runaway electrons

Published on November 07, 2024

Fusion researcher Tijs Wijkamp received a EUROfusion Bernard Bigot Researcher Grant (ERG) to study runaway electrons, which can damage the inside of a fusion reactor if they are not properly dealt with. EUROfusion interviewed him on how the ERG stimulates connecting with other experts.

Can you tell us a bit about yourself?

“Fusion caught my eye when I was looking for a challenging master’s programme in applied physics. I wanted to study a topic with a clear societal goal and the fusion master at the Eindhoven University of Technology in the Netherlands fit perfectly. I enjoyed it so much that I decided to pursue a PhD with that university in collaboration with the Dutch EUROfusion member DIFFER , which took me across Europe to the tokamaks TCV in Switzerland (Swiss Plasma Center) and MAST Upgrade in the UK (UKAEA).”

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Tijs Wijkamp
Tijs Wijkamp – photo credit: DIFFER / Kim Vos Photography

What is your ERG project about?

“In my ERG project I want to look at the phenomenon of runaway electrons, which can damage the inner walls of your fusion reactor if you don’t deal with them. Those are beams of charged particles that are boosted close to lightspeed after so-called disruptions — unwanted collapses of the fusion plasma. You have to gracefully diffuse their impact, otherwise they will hit the walls of the reactor in one tight spot and cause damage.”

What does your research look like in practice?

“The system I will use in this project is the MANTIS camera that I worked with during my PhD research, developed by DIFFER, EPFL and MIT. It was originally designed to study cold plasma’s near the exhaust of a fusion reactor, but it turned out that MANTIS can also see the synchrotron light from runaway electrons.”

“My goal is to study the planned mitigation strategy for these runaways in the next-generation tokamaks like ITER, which comes down to injecting just the right amount of hydrogen into the plasma. That way we cause a diffusive landing of the electron beam upon a triggered secondary disruption. This will be done through participation in dedicated EUROfusion experiments on TCV and on the larger German tokamak ASDEX Upgrade. By comparing how the neutral hydrogen, plasma and runaway electrons change behaviour between tokamaks of different sizes, we will be able to validate predictions for the optimum strategy to use in reactor-sized tokamaks like the international ITER project.”

How did you end up applying for an ERG grant?

“The core of my ERG proposal sort of wrote itself in the back of my head when I was writing the conclusions for my PhD thesis! The ERGs are completely dedicated to fusion, like my research proposal — it would have been difficult to pitch this technical topic to more general grants.

What do ERG grants enable you to do?

“The great thing about the ERG grants is that they are tailored to fusion. Like other grants, the ERGs let you focus on your research for a couple of years without the worries of job hunting. But they also have a baked-in budget for missions to fusion sites across Europe, because EUROfusion understands that you need to visit different labs and topical experts. With other grants, these opportunities are less self-evident.”

What are the steps you are most looking forward to?

“The new collaborations, places and people I will get to meet. I will work closely with the ASDEX-Upgrade experimental team; it will be great to see what we will discover when their new MANTIS first opens its eyes. The light from runaway electrons will be even clearer there than in TCV! I also look forward to collaborating with Aaro Järvinen at VTT in Finland (recipient of a EUROfusion AI for Fusion grant). The plan is for him to train me in how to use his computer codes to analyse the data about runaway electrons.”

Finally, do you have any advice for future applicants to an ERG?

“Find yourself a research goal that you are really enthusiastic about, where you know exactly how it contributes to the goals of the European fusion programme. If you have those two ingredients, you will be able to convince people why your project should definitely be funded.”

Author: Gieljan de Vries (EUROfusion)

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