The solution-cathode glow discharge in slow motion: characterization of glow discharge filament structure and droplet ejection using a rectangular capillary

A solution-cathode glow discharge (SCGD) using a novel rectangular-shaped cathode capillary is used to study aspects of the plasma-liquid interface. High-speed video of the plasma-liquid interface captured simultaneously with low-angle laser scattering from droplets near the plasma-liquid interface are studied in concert to evaluate potential mechanisms related to surface-plasma interaction. Frame-by-frame analysis of high-speed video allows estimation of droplet number density, translational speed, and rate of ejection. The data are evaluated to provide insight into potential mechanisms of analyte transport that are of importance for the use of SCGD in analytical atomic spectrometry. [Display omitted] •A Rectangular Capillary is Used to Sustain the Solution-Cathode Glow Discharge (SCGD).•High-Speed Video Analysis Reveals Formation of Electrostatic Liquid Jets in Cathode Filaments.•Frame-by-Frame Video Analysis Quantifies Cathode Current Density and Droplet Formation Rate.•The SCGD is Found to Operate at Constant Current Density Independent of Cathode Size.•SCGD Analytical Performance is Improved Using Rectangular Capillary.