Design and characterization of a dust dispenser for tungsten dust injection experiments in the STOR-M tokamak

Abstract

A dust dispenser has been designed and characterized for future experiments in the STOR-M tokamak. Controlled dust injection is demonstrated in a test-bench device and characterized with different techniques. Upon activation of the dispenser, a plume of dust particles is dispensed. The particle size distribution is found using scanning electron emission images. A laser is used to illuminate the falling particles dispensed and a fast video camera is used to track the images of those particles. The evolution of the spatial distribution of the falling particles is reconstructed using those images based on a free-fall model. The total mass of the dispensed dust particles is directly measured using an analytic balance and is also inferred from the intensity of the scattered light recorded by the video camera.

Keywords:

• Dust dispenser
• particle tracking velocimetry
• tungsten microparticles
• fast video camera imaging
• plasma wall interactions
• tokamak

Acknowledgments

Tungsten micro-powder was graciously provided by the French alternative energies and atomic energy commission (CEA), Cadarache, France.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Research funding provided by Natural Sciences and Engineering Research Council (NSERC) of Canada is appreciated (L. Couedel, C. Xiao). Scholarships provided by NSERC and the University of Saskatchewan are appreciated (N. Nelson).

Notes on contributors

N. Nelson

Mr N. Nelson is a PhD student at the University of Saskatchewan since January 2021. He obtained his BSc in Engineering in 2015 and MSc in 2020 from the University of Saskatchewan. He has received a Mitacs Globalink Research Award and will work at Aix-Marseille and CEA Cadarache in 2022 for six months. Mr. Nathan Nelson is an experimental plasma physicist. His current research interests are tokamak dust studies, plasma wall interactions and plasma facing component analysis.

L. Couëdel

Dr L. Couedel has been an Associate Professor at the University of Saskatchewan (USask), Saskatoon since March 2018. He obtained his PhD from the University of Sydney, Australia in 2008. He was a postdoctoral fellow at the Max-Planck Institute for extraterrestrial Physics in the group of Professor Gregor Morfill (2009-2011). Prior to joining the USask, Dr. Couedel was a CNRS researcher in the PIIM laboratory at Aix-Marseille University (2011-2018). Dr. Couedel is an experimental plasma physicist. His current research interests are complex (dusty) plasmas (especially nanoparticle growth in low temperature plasmas (magnetized and unmagnetized), dust in tokamaks and instabilities in complex plasma crystals) and low temperature plasma diagnostics (especially sheath diagnostics).

C. Xiao

Dr C. Xiao received his BSc (1982) and MSc (1984) degrees from the University of Science and Technology of China, Hefei, China and his PhD (Dr.rer.nat., 1990) degree from the Ruhr-University Bochum, Germany. He is currently a professor in the Department of Physics and Engineering Physics, University of Saskatchewan, Canada. His current research interests include the physics, engineering, and application aspects related to plasma diagnostics and plasma devices such as tokamak, reversed field pinch, compact torus injector, and dense plasma focus. He is responsible for operation and research projects on the STOR-M tokamak and the University of Saskatchewan Compact Torus Injector.