High-speed imaging of turbulent fluctuations in TJ-K

Mesoscale (i. e. larger than microscopic but smaller than the system size) turbulent fluctu-ations of high density, often referred to as "blobs", may be a part of the explanation of the intermittent transport observed in the scrape-off layer (SOL) of many fusion experiments. The understanding of those mesoscale events has improved a lot over the recent years [1]. However, the details about the generation and the precise relevance for the SOL transport remain still unknown. Fast cameras are gaining more and more importance in studies of those events, since they can observe a large area of the plasma simultaneously, ideally without the need to disturb the plasma. However, the fact that they integrate the light signal along the line of sight makes the interpretation of the data more challenging. Yet it was possible to localize the turbulent fluctuations visible in the image data in the physical coordinates of TJ-K.