Bulletin of the American Physical Society
74th Annual Gaseous Electronics Conference
Volume 66, Number 7
Monday–Friday, October 4–8, 2021;
Virtual: GEC Platform
Time Zone: Central Daylight Time, USA
Session RR41: Atmospheric and High Pressure Plasmas: Jets and Gliding Arcs III |
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Chair: Mark Kushner, University of Michigan Room: Virtual GEC platform |
Thursday, October 7, 2021 2:00PM - 2:15PM |
RR41.00001: Vibrational Excitation of Nitrogen in Atmospheric Pressure Plasma Jets Sustained by Ns Pulse and RF Waveforms Caleb Richards, Elijah R Jans, Igor V Adamovich Time-resolved N2 vibrational temperature and translational-rotational temperature in quasi-two-dimensional atmospheric pressure plasma jets excited by ns pulse and RF discharges are measured by broadband vibrational CARS, in collinear phase matching geometry. As expected, the results indicate much stronger vibrational excitation in the RF plasma jet due to both lower reduced electric field and higher coupled power. In a ns pulse discharge in N2/He, N2 vibrational temperature is significantly lower compared to that in N2/Ar, due to the more rapid V-T relaxation of nitrogen by helium atoms. In the RF plasma jets in N2/Ne and N2/Ar, the vibrational excitation increases considerably as the nitrogen fraction in the mixture is reduced. The experimental data in the RF plasma jet in N2/Ar jet are compared with kinetic modeling predictions. The model solves the electron energy equation, the heavy species energy equation, and equations for the species concentrations. It incorporates electron impact ionization, dissociation, electronic excitation, and vibrational excitation processes; energy transfer among the excited electronic states of Ar and N2; and N2 vibrational relaxation (state-specific vibration-vibration energy transfer for N2-N2 and vibration-translation relaxation for N2-N). |
Thursday, October 7, 2021 2:15PM - 2:30PM |
RR41.00002: Fast Imaging Reveals the Dynamic of Plasma Discharge sustained with Ultra-short Microwave Pulses at Atmospheric Pressure Sergey Soldatov, Guido Link, Dineshkumar Kanesan, John Jelonnek
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Thursday, October 7, 2021 2:30PM - 2:45PM |
RR41.00003: Zero-dimensional simulations of He/N2(v<58)/O2 (v<41) microscale atmospheric-pressure plasma jets: Validation with a focus on NO density Youfan He, Patrick Preissing, David Steuer, Maximilian Klich, Volker Schulz-von der Gathen, Marc Böke, Ihor Korolov, Julian Schulze, Vasco Guerra, Ralf Peter Brinkmann, Efe Kemaneci Reactive oxygen and nitrogen species produced by atmospheric-pressure plasma jets are of importance in biomedical applications, e.g., nitric oxide (NO) for wound healing. The jets are investigated by zero-dimensional (volume-averaged) and pseudo-one-dimensional (plug-flow) models, coupled with the Boltzmann equation under the two-term approximation to self-consistently calculate the electron energy distribution function. The simulation results are validated against a wide variety of measurements in He, N2, He/O2, He/N2 and He/N2/O2 plasmas. The NO density is determined as a function of the gas mixture ratio, helium flow rate and absorbed power. A larger hypothetical “effective” rate coefficient value is necessary for the reactive quenching N2(A3Σ, B3Π; v=0) + O(3P) → NO + N(2D) in the simulations to better capture the NO density measurements at low power. This indicates that in this quenching the species N2(A3Σ, B3Π; v>0) and multiple higher N2 electronically excited states also play an underlying role in NO production at low power. The sensitivity of the simulated plasma properties to the N2(v) and O2(v) resolutions, the wall reaction probabilities and the synthetic air impurity levels is uncovered. |
Thursday, October 7, 2021 2:45PM - 3:00PM |
RR41.00004: 3-dimensional density distributions of NO in the effluent of a micro atmospheric pressure plasma jet operated in He/N2/O2 mixture Patrick Preissing, Ihor Korolov, Julian Schulze, Marc Böke, Volker Schulz-von der Gathen Plasma jets are known to generate a huge number of different reactive species. In that context Nitric Oxide (NO) is one of the key players, as it triggers many biological processes and it is also considered the only radical that is stable enough to act as an extracellular messenger. In this study absolute ground state densities of NO are measured in the effluent of an RF-driven micro atmospheric pressure plasma jet (µAPPJ), that is operated in a He/N2/O2 mixture, by means of Laser Induced Fluorescence (LIF), with three-dimensional spatial resolution. The densities are measured in two distinct atmospheres. In the first one, the jet is expanding into open air, whereas in the second configuration the jet is expanding into a controlled He/ synthetic air mixture. From the time resolved LIF signals the quenching coefficients for He, air, N2 and O2 are determined, as well as the intrusion of the ambient air into the He gas flow expanding from the jet. It was found that the distribution as well as the absolute densities strongly depend on the surrounding atmosphere, due to quenching and collisions. Furthermore, the NO particles are strongly coupled to the He flow of the feed gas. Parameter studies, varying different parameters such as plasma power, gas flow and gas mixture have been performed and the influence on the absolute NO densities as well as its distributions are investigated. |
Thursday, October 7, 2021 3:00PM - 3:15PM |
RR41.00005: 2d spatially resolved O atom density profiles in an atmospheric pressure plasma jet: from the active plasma volume to the effluent David Steuer, Ihor Korolov, Sascha Chur, Julian Schulze, Volker Schulz-von der Gathen, Judith Golda, Marc Böke Micro atmospheric pressure plasma jets (µAPPJs) are attracting high attention due to their potential to treat temperature sensitive surfaces. For these applications, reactive species are produced in the plasma. In this work two-dimensional spatially resolved absolute atomic oxygen densities are measured within a µAPPJ (COST-Jet) and in its effluent. The plasma is operated in helium with an admixture of 0.5% of oxygen at 13.56 MHz and with a power of 1 W. Absolute atomic oxygen densities are obtained using two photon absorption laser induced fluorescence spectroscopy (TALIF). The results are reproduced by a combination of phase resolved optical emission spectroscopy (PROES) measurements and simple model calculations. Within the discharge, the atomic oxygen density builds up with a rise time of 600 µs along the gas flow and reaches a plateau of 8x1015 cm-3. In the effluent, the density decays exponentially with a decay time of 180 µs (corresponding to a decay length of 3 mm at a gas flow of 1.0 slm). It is found that both, the species formation behavior and the maximum distance between the jet nozzle and substrates for possible oxygen treatments of surfaces can be controlled by adjusting the gas flow. |
Thursday, October 7, 2021 3:15PM - 3:30PM |
RR41.00006: Efficient Generation of OH Radicals Using Atmospheric Pressure DC Glow Discharge with Two Intersecting Gas Flows Naoki Shirai, Hiroki Owada, Koichi Sasaki
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