Artur Perek built the MANTIS camera, rewrote the software, and contributed to solving the difficult problem of divertor detachment: cooling plasma before it hits the tokamak wall. Perek loved every inch of his PhD.
“My PhD involved solving problem after problem. Luckily, I really enjoy solving problems.” Perek worked on the MANTIS camera system that monitors the plasma within a fusion reactor. It helps controllers to make sure that the plasma that ends up at the exhaust - the divertor - is not too hot. “When I started my PhD, the components of the camera were ordered and piling up. My goal was to build it, install it on the Swiss TCV tokamak of EPFL, and enable its use for control.”
Hacking the software
The MANTIS camera was of a high quality, but the software that came with it was not designed to match this performance. “We analyze the plasma 800 times per second. The software turned out to be too slow, so I decided to improve it. ”It became Perek’s most challenging and successful project. He had to go down to the most essential bits and bytes. He built an exploit (a piece of code) that bypassed the original software and improved the stability to microseconds. He sent the new software to the camera manufacturer. They acknowledged the quality and offered him a job. He declined, preferring to work in research instead.
More work to do
The MANTIS camera is installed on the TCV tokamak. Perek developed an analysis to obtain plasma densities and temperatures from the images. These reveal the temperature at the divertor and allow the operators to control that temperature. Recently, a full control system earned the researchers a Nature Communications paper.
Perek expects to defend his PhD thesis in fall 2021. He might apply for a job on the follow-up project at DIFFER and EPFL: “MANTIS actually has ten cameras, not just the one we use. Using them all would drastically improve detachment control, but it requires far faster models.”
Another unsolved problem to go. Perek likes it.
Text Bastienne Wentzel, photo Bart van Overbeeke/DIFFER. This interview is published in the DIFFER Annual Report 2020.
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