Happy first of Advent!
We’re lighting the first candle on our scientific Advent wreath.
As we approach the festive season, we are shining a light on the intersection of science and tradition. Inspired by the Advent wreath, the DOLPHIN group, led by Andreas Döpp, has created a playful project showcasing techniques normally applied in their high-power laser experiments at the Centre for Advanced Laser Applications (CALA).
Each Sunday, we'll be lighting a candle - a weakly ionized plasma – on our scientific Advent wreath. This week, we're highlighting the power of high-speed cameras in capturing fast transient phenomena.
Watch as the researchers use a high-speed camera to capture the intricate dance of a flame detaching from a candle. This phenomenon, technically known as flame liftoff, is described in the review "Ignition, Liftoff, and Extinction of Gaseous Diffusion Flames" by Liñán, Vera, and Sánchez (2015).
Ideally, a flame anchors itself by burning back towards the wick as fast as the fuel rises. However, when the airflow velocity becomes faster than the flame's ability to burn upstream, the flame is overpowered. Much like a swimmer unable to fight a strong current, the flame is pushed away from its fuel source until it disconnects completely and extinguishes.
Instruments like a commercial high-speed camera allow us to observe such rapid processes in detail, revealing mechanisms that are completely invisible to the naked eye. This allows for instance the study of gas dynamics in targets for laser-plasma accelerators. At DOLPHIN, even more advanced cameras are developed, aiming for billions of images per second to observe in real time how light interacts with matter.
Pictures: Advent candles: AI-generated / Nina Beier; High-Speed Measurement: Matilde Nunes, Johannes Altmann and Marguerite Dion