Science on Saturday: Diagnosing fusion plasmas - How to perform measurements in a 100 million degree environment?

Feb 5, 2022, 9:30 am11:00 am
Online via Zoom
  • Dr. Andrew Zwicker, Head, Communications & Public Outreach
  • Ms. Deedee Ortiz, Program Manager, Science Education
Event Description


High temperature plasma diagnostics have been fundamental to characterize and understand the conditions for fusion energy. New measurements can even trigger paradigm shifts. For example, in the 1970’s the tokamak became the main magnetic confinement concept because its superior energy confinement was experimentally verified by first Thomson scattering measurements.This lecture provides a high level overview of high temperature plasma diagnostic concepts. I will introduce the challenges that magnetic confinement fusions reactors pose to practical measurements. Using a working example of the recently implemented LLAMA diagnostic, I will outline the path from the need to measure a certain plasma quantity, to a conceptual measurement principle towards an actual implementation on a fusion device. LLAMA is the Lyman Alpha Measurement Apparatus, which measures hydrocgenic ultraviolet radiation to infer the neutral particle density and ionization source. These previously underdetermined quantities are very important to accurately model the tokamak plasma edge.The lecture closes with an outlook on how measurements and diagnostics need to evolve for deployment in first fusion power plants.


Florian Laggner is an experimental physicist at Princeton Plasma Physics Laboratory working on the DIII-D National Fusion Facility in San Diego, California. He received his PhD degree from TU Wien, Vienna, Austria, in 2017, studying the inter-ELM evolution of the pedestal structure at the ASDEX Upgrade tokamak. In 2017, Florian joined the Plasma Control group at Princeton University as a postdoctoral researcher and in 2019 he became a research scientist at PPPL. 
Florian's main research focus is the plasma edge region and plasma diagnostics, with a particular focus on the edge pedestal profile structure. He is presently working on the LLAMA diagnostic, which stands for Lyman Alpha Measurement Apparatus, that enables the measurement of edge neutral density profiles. Bio fact unrelated to science: Before grad school, Florian was pursuing a career as handball player, winning the Austrian championship.