Characterization and Infrared Emission Spectroscopy of Ball Plasmoid Discharges

Abstract

Plasmas at atmospheric pressure serve many purposes, from ionization sources for ambient mass spectrometry (AMS) to plasma-assisted wound healing. Of the many naturally occurring ambient plasmas, ball lightning is one of the least understood; there is currently no solid explanation in the literature for the formation and lifetime of natural ball lightning. With the first measurements of naturally occurring ball lightning being reported last year, a we have worked to replicate the natural phenomenon in order to elucidate the physical and chemical processes by which the plasma is sustained at ambient conditions. We are able to generate ball-shaped plasmoids (self-sustaining plasmas) that are analogous to natural ball lightning using a high-voltage, high-current, pulsed DC system. b Improvements to the discharge electronics used in our laboratory and characterization of the plasmoids that are generated from this system will be described. Infrared emission spectroscopy of these plasmoids reveals emission from water and hydroxyl radical-fitting methods for these molecular species in the complex experimental spectra will be presented. Rotational temperatures for the stretching and bending modes of H 2 O along with that of OH will be presented, and the non-equilibrium nature of the plasmoid will be discussed in this context.