Bulletin of the American Physical Society
70th Annual Gaseous Electronics Conference
Volume 62, Number 10
Monday–Friday, November 6–10, 2017; Pittsburgh, Pennsylvania
Session VF2: Gas Phase Plasma Chemistry II |
Hide Abstracts |
Chair: David Staack, Texas A&M University Room: Duquesne |
Friday, November 10, 2017 8:00AM - 8:15AM |
VF2.00001: Plasma chemistry model of microdischarge in flowing humid air directly heated by discharge Changho Yi, Sung-Young Yoon, Sangheum Eom, Seungil Park, Seong Bong Kim, Seungmin Ryu, Suk Jae Yoo We present a numerical model of microdischarge in humid air of atmospheric pressure considering the effects of direct ohmic heating of discharge layer and heat and particle transport by flow. The model consists of three coupled well-mixed regions of hot discharge layer, warm afterglow layer, and cold large volume layer, which interact with each other through thermal conduction, diffusion, and particle flow. The calculated results and experimental results of Fourier transformed infrared absorption spectroscopy shows reasonable agreements for dynamics of various reactive oxygen and nitrogen species, and showed large discrepancy when ohmic heating in discharge layer was ignored. These results indicate that localized ohmic heating by microdischarge substantially affected on the chemical reactions with temperature dependence. Heat and particle transport by flow also affected on dynamics of reactive neutral species in various gas flow configurations. Hence, the deposition and transfer of both heat and species should be considered together to properly calculate the dynamics of reactive neutral species in microdischarges. [Preview Abstract] |
Friday, November 10, 2017 8:15AM - 8:30AM |
VF2.00002: Efect of discharge tube temperature on the densities of ${\rm N}_2({\rm A}^3\Sigma_u^+)$ and atomic nitrogen in a remote nitrogen plasma source Masaharu Shimabayashi, Kazuaki Kurihara, Koichi Sasaki We investigate the application of a remote nitrogen plasma source to the surface nitriding of SiC. In this work, we tried the control of the densities of reactive nitrogen species (${\rm N}_2({\rm A}^3\Sigma_u^+)$ and atomic nitrogen) by the temperature of the discharge tube. The remote nitrogen plasma was produced using a microwave resonator (2.45 GHz) which was installed on the outside of a discharge tube with an inner diameter of 8 mm. The microwave resonator was located at a distance of 7-16 cm from the measurement position. A part of the discharge tube between the resonator and the measurement position was heated up to 600 $^{\rm o}$C by applying a heating power to a kanthal spiral wire on the outside of the discharge tube. We observed the slight increase (several tens of percent) in the density of atomic nitrogen by the discharge tube heating. On the other hand, the density of ${\rm N}_2({\rm A}^3\Sigma_u^+)$ decreased significantly (an order of magnitude) with the discharge tube temperature. These results indicate that the high temperature of the discharge tube affects the loss frequencies of atomic nitrogen and ${\rm N}_2({\rm A}^3\Sigma_u^+)$ oppositely. [Preview Abstract] |
Friday, November 10, 2017 8:30AM - 8:45AM |
VF2.00003: Sensitivity analysis and uncertainty quantification for the electric field determination in air from FNS and SPS ratio Zdenek Bonaventura, Petr Bilek, Adam Obrusnik, Tomas Hoder, Milan Simek Frequently used method for the determination of the electric field in discharges in air is based on the measurement of the ratio of luminous intensities emitted by radiative states of ${\rm N_2}(C^3 \Pi_{\rm u})$ (second positive system) and ${\rm N^{+}_2}(B^2 \Sigma_{\rm u})$ (first negative system This method is used for wide range of pressures from ground pressures, where it is applied for example to investigation of dielectric barrier discharge, up to ionospheric altitudes for remote sensing of Transient Luminous Events, e.g., lightnings, sprites and blue jets. It is well know that quenching rates of ${\rm N_2}(C^3 \Pi_{\rm u})$ and ${\rm N^{+}_2}(B^2 \Sigma_{\rm u})$ determined by various experimental methods exhibit serious discrepancies. Therefore we aim to investigate the impact of uncertainties in values of these rates on the electric field determined from FNS/SPS ratio. We present uncertainty quantification and sensitivity analysis for the kinetic scheme for resulting ratio of the FNS and the SPS. This analysis is based on the Elementary Effects (EEs) method invented by Morris. Uncertainty quantification based on Monte Carlo methods will be applied. [Preview Abstract] |
Friday, November 10, 2017 8:45AM - 9:00AM |
VF2.00004: OH generation in a pulsed He plasma jet with water electrode Shutong Song, Chunqi Jiang The highly reactive hydroxyl radicals play a key role in various biomedical applications such as surface decontamination, wound disinfection and cancer treatment. This study investigated a needle-electrode pulsed helium plasma jet interacting with a water-covered ground electrode via electrical model and optical emission spectroscopy. The helium plasma jet driven by 6 kV pulses with varied pulse duration at 1 kHz was generated and impinged onto the water surface with an inter-electrode gap of 10 mm. An equivalent circuit, composed of a 6.3 pF capacitor which represented the capacitive jet device and in parallel with an adjustable resistor and capacitor in series for the plasma plume, can be used to model the plasma system based on the voltage-current waveforms. Optical emission spectroscopy revealed that total OH intensity along the plume increased with longer pulse duration in a range from 200 ns to 900 us. However, the OH energy yield, indicating the energy efficiency of OH production, is the highest at a pulse duration of 800 ns and 7.5 times higher compared to the second-highest at 900 us. Plume temperature were measured at different pulse durations and are further discussed assisted with modeling of OH (A$^{\mathrm{2}}\Sigma $-X$^{\mathrm{2}}\Pi )$ emission spectra. [Preview Abstract] |
Friday, November 10, 2017 9:00AM - 9:15AM |
VF2.00005: Chemical Kinetics Mechanisms Study of High Electron Density Argon-Water Filamentary Discharges* Yuchen Luo, Amanda Lietz, Mark Kushner, Peter Bruggeman Although the plasma kinetics of He-H$_{\mathrm{2}}$O mixtures has been investigated for diffuse low electron density atmospheric pressure glow discharges, the kinetics of high electron density filamentary discharges is less well known. In this work, we study the kinetics of a filamentary nanosecond pulsed Ar$+$0.26{\%} H$_{\mathrm{2}}$O plasma using a 0D chemical kinetics model with comparison to previously measured OH and H densities by time resolved laser induced fluorescence (LIF) and two-photon absorption LIF [1]. Good agreement is obtained for absolute values of the H and OH densities. There are, however, discrepancies between the model and the experiment and the origin of these discrepancies will be discussed. Results from the model indicate that the production of H/OH involve electron dissociative recombination reactions with water ions and its clusters. H and OH consumption in the afterglow are due to radical-radical recombination. The significantly lower density of OH compared to the H density is due to electron induced dissociation of OH during the discharge pulse and enhanced recombination by the large O density in the afterglow. Effects of air impurities, local depletion of water at the filament position and transport on the OH kinetics will also be discussed. [1] Yatom et al. (submitted) [Preview Abstract] |
Friday, November 10, 2017 9:15AM - 9:30AM |
VF2.00006: Spatially Resolved Ozone Density in Volumetric and Surface Dielectric Barrier Discharges via Absorption Spectroscopy Ryan T. Smith, Björn Offerhaus, Friederike Kogelheide, Nikita Bibinov, Peter Awakowicz, Katharina Stapelmann Absorption spectroscopy is performed on two different Dielectric Barrier Discharges, a Surface (SDBD) and a Volumetric (VDBD), in order to measure the Ozone (O$_3$) density within the gas phase. A Laser Driven Light Source (LDLS) is used as a very stable, high intensity broad-band source between 170 nm and 2400 nm. The light emitted from the collimated LDLS and the plasma are shown through a narrow band filter at 253.7 $\pm$ 5 nm to isolate the O$_3$ Hartley band centered about 253.65 nm. Absorption measurements are performed on both the SDBD and VDBD at atmospheric pressure under varying gas mixtures and at flows of 10 slm and 2 slm, respectively. Spatial resolution is achieved on the order of 0.1 mm with a CCD camera. Furthermore, measurements are taken at multiple frequencies and peak to peak voltages resulting in varying power densities. A direct comparison of the gas phase O$_3$ is made at the same operating frequency and power density of the two plasma sources. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700