Measurements of Emitted Molecular Species in Non-Uniform Plasma Arcs*

Plasma applications ranging from industrial plasma modification of materials to fusion experiments often involve intense plasma-material interactions. Diagnosing the background plasma and emitted materials as they interact improves our understanding of these systems.  In particular, molecular species can be present in large concentrations in plasmas of sufficiently low electron temperature.  Infrared absorption spectroscopy is a common tool for diagnosing molecular species and properties of these species such as vibrational and rotational temperatures.  An experiment to study the interactions and decomposition of an alkali salt into a plasma arc using infrared absorption spectroscopy is presented.  The experiment applies previous work [1] to improve the spatial resolution of the infrared absorption measurement to understand the structure of the arc and the resulting interactions with the emitted materials.

[1] McGreivy, N., & Jaworski, M. (in press). Methods of improving spatial resolution for IR spectroscopy in atmospheric-pressure plasma systems. Review of Scientific Instruments