Max Planck Institute for Plasma Physics (IPP), Greifswald
Monitoring Plasma at Wendelstein 7-X
What will the energy supply of the future look like? The Max Planck Institute for Plasma Physics (IPP) in Greifswald is dealing with this question while working with Wendelstein 7-X, the world‘s largest stellarator-type nuclear fusion facility. The aim is to achieve plasma discharges lasting up to 30 minutes with this plant.
Graphite Tiles Protect Divertor from High Plasma Temperatures
Temperature measurements in this context play a central role. At Wendelstein 7-X graphite tiles are thermographically monitored which cover parts of the inner plasma vessel, the divertor. The tiles allow higher temperatures and longer plasma discharges. The temperature control is intended to prevent the system from being damaged by overloading and possible damage to the tile elements caused by plasma discharges not being detected.
This task is performed by special endoscopes equipped with models of the infrared camera series ImageIR® 9300 from InfraTec and visual cameras. The thermographic cameras are positioned at the end of each endoscope. Their internal filter wheel is equipped with multiple neutral density filters, providing the basis for accurate measurements over the entire, very wide temperature measurement range.
High-resolution detectors with (1,280 × 1,024) IR pixels and corresponding special lenses ensure that large areas of the horizontal and vertical fields of the divertor can be monitored with a single image. The option of taking partial images at speeds of several kilohertz enables to record even extremely short-term temperature changes.