What is it about?
This paper explains how a new multi-frequency reflectometry diagnostic was built for the ASDEX-Upgrade tokamak. This diagnostic allows sampling 7 different positions simultaneously, and it allows us to zoom-in or zoom-out in specific plasma regions with a single instrument. This flexibility is unique and we managed to make it happen with traditional detectors.
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Photo by Jan Huber on Unsplash
Why is it important?
Most instruments with multiple frequencies only allow a fixed configuration. Our instrument allows changes to the multi-frequency configuration within experiments and even inside a single experiment. We achieve this with double down-convertion and using traditional I/Q detection. Nothing fancy.
Perspectives
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I think this diagnostic shows that a little creativity and patience with the IF hardware design allows a flexible multi-channel DBS/reflectometry diagnostic to be created. This opens up a large amount of cross-correlation studies across fast events in the plasma such as the LH transition and/or ELM instabilities.
Pedro Molina Cabrera
Ecole Polytechnique Federale de Lausanne
Read the Original
This page is a summary of: W-band tunable, multi-channel, frequency comb Doppler backscattering diagnostic in the ASDEX-Upgrade tokamak, Review of Scientific Instruments, August 2023, American Institute of Physics,
DOI: 10.1063/5.0151271.
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