@article{morsell_dechant_gall_trosan_lietz_stapelmann_shannon_2024, title={Estimation of mean electron energy in helium surface ionization waves on dielectric substrates}, volume={57}, ISSN={["1361-6463"]}, url={https://doi.org/10.1088/1361-6463/ad5451}, DOI={10.1088/1361-6463/ad5451}, abstractNote={Abstract The determination of basic plasma parameters in atmospheric pressure discharges is critical to advancing their use in applications. Atmospheric pressure plasma jets have found use in the fields of medicine, agriculture, material modification and others. Atmospheric pressure plasma jets often generate plasma surface ionization waves (SIW) which interact with and propagate over surfaces. Electrical diagnostics are challenging in SIW due to high collision frequencies and small scale of the plasma discharge. This work employs a passive optical emission line ratio technique to estimate the mean electron energy in SIW over planar dielectric substrates. The method uses an intensity ratio of two helium triplet lines: He( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>3</mml:mn> <mml:msup> <mml:mrow/> <mml:mn>3</mml:mn> </mml:msup> <mml:mi>S</mml:mi> </mml:mrow> </mml:math> ) at 706.5 nm and He( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>3</mml:mn> <mml:msup> <mml:mrow/> <mml:mn>3</mml:mn> </mml:msup> <mml:mi>D</mml:mi> </mml:mrow> </mml:math> ) at 587.56 nm. A collisional-radiative model is used to correlate line ratio to mean electron energy and determine dependencies on electron density and He/air gas mixture. Mean electron energies ranging from 3–8 eV are determined in He/air mixtures and are found to remain constant as the surface wave propagates radially. This work provides a 2D, time-resolved, mean electron energy diagnostic for surface ionization wave propagation and validation of numerical modeling in atmospheric pressure systems with spatially varying He/air gas mixtures. The model in question is designed for use with any He line ratio in the n = 3 excitation level.}, number={39}, journal={JOURNAL OF PHYSICS D-APPLIED PHYSICS}, author={Morsell, Joshua and Dechant, Corey and Gall, Grayson and Trosan, Duncan and Lietz, Amanda M. and Stapelmann, Katharina and Shannon, Steven}, year={2024}, month={Oct} }
 @article{trosan_walther_mclaughlin_salvi_mazzeo_stapelmann_2023, title={Analysis of the effects of complex electrode geometries on the energy deposition and temporally and spatially & nbsp;averaged electric field measurements of surface dielectric barrier discharges}, volume={9}, ISSN={["1612-8869"]}, url={https://doi.org/10.1002/ppap.202300133}, DOI={10.1002/ppap.202300133}, abstractNote={AbstractSurface dielectric barrier discharges (SDBDs) have been gaining interest in part due to their scalability and flexibility of materials used, allowing larger electrodes with more complex geometries. This paper seeks to elucidate the properties of SDBD geometries utilizing differing repeated lattice structures. Voltage and current traces, optical emission spectroscopy, digital imaging, and numerical analysis are used to analyze the electrodes. Temporally and spatially averaged reduced electric fields and the total power deposited into the plasma are presented. The averaged reduced electric field is not significantly affected by increasing applied voltage, but minor variations could be observed due to the geometry of the electrode lattice structures. Finally, plasma power does not track linearly with perimeter in these more complicated lattice structures.}, journal={PLASMA PROCESSES AND POLYMERS}, author={Trosan, Duncan and Walther, Patrick and Mclaughlin, Stephen and Salvi, Deepti and Mazzeo, Aaron and Stapelmann, Katharina}, year={2023}, month={Sep} }
 @article{morsell_trosan_stapelmann_shannon_2023, title={Plasma surface ionization wave interactions with single channels}, volume={32}, ISSN={["1361-6595"]}, url={https://doi.org/10.1088/1361-6595/acf9c9}, DOI={10.1088/1361-6595/acf9c9}, abstractNote={Abstract
               The study of plasma surface ionization waves (SIWs) in recent years has primarily focused on planar surfaces and periodic two dimensional structures. In application, substrates are likely to have non-planar morphology such as cracks, pores, and steps. Additionally, targets for the applications of medicine or catalysis may have targets with heterogeneous composition. This classification of targets are brought under the umbrella of complex interfaces. In this work, plasma SIWs were incident on a complex target consisting of a single channel cut into glass slides. The SIW velocities for the in-channel portion of the wave and radially propagating portion of the wave were tracked. It was found that surface wave velocities are not significantly affected by channel geometry, but primarily increase with pulse energy. A third propagation direction for the SIW is characterized in the azimuthal direction relative to the radial portion of the wave. Channel geometry is found to greatly effect the area treated by the plasma but not the propagation velocity of the surface wave. Surface wave morphology and the impact on application is also discussed. A simple model was introduced to understand the mechanisms behind SIW escape from a channel. It was found that the ratio of pulse energy to a geometry dependent minimum energy can predict the escape angle of a SIW from single channels.}, number={9}, journal={PLASMA SOURCES SCIENCE & TECHNOLOGY}, author={Morsell, Joshua and Trosan, Duncan and Stapelmann, Katharina and Shannon, Steven}, year={2023}, month={Sep} }