Bulletin of the American Physical Society
73rd Annual Gaseous Electronics Virtual Conference
Volume 65, Number 10
Monday–Friday, October 5–9, 2020; Time Zone: Central Daylight Time, USA.
Session RW2: Poster Session IV (4:30pm - 6:30pm)On Demand
|
Hide Abstracts |
|
RW2.00001: Examining the Effects of Changing Plasma Parameters on Peroxide Production in the Effluent and Liquid Phase Using a Cost Reference Jet Brayden Myers, Katharina Stapelmann Hydrogen peroxide has been shown to be one of the most important long lived species for biomedical applications of plasma [1-3]. Understanding the production mechanisms and origin of peroxide in atmospheric pressure plasmas is beneficial for both isolating the effects of short lived reactive species and investigating chemical pathways in plasma treated liquid. Additionally, this information can be helpful for regulating the amount of hydrogen peroxide delivered to a designated area or solution. To this end, hydrogen peroxide concentrations were measured colorimetrically after plasma treatment with the COST Reference Microplasma Jet [4] for a variety of different solutions, including organics, spin traps, cell medium, and buffer. Plasma parameters were varied to include applied voltage, gas admixture, and treatment distance. These measurements, in conjunction with EPR measurements using the spin trap DMPO, show that peroxide concentrations and the location of its production (gas/liquid phase) can be mediated by both plasma and solution properties. [Preview Abstract] |
|
RW2.00002: Computational and experimental studies of plasma stratification in noble gases and nitrogen Vladimir Kolobov, Malik Tahiyat, Tanvir Farouk, Gabe Xu Recent advances of computational tools allow simulations of plasma stratification in atomic and molecular gases. Moving striations in diffuse and constricted DC discharges and standing striations in Capacitively Coupled Plasma in argon have been reproduced in computer simulations [1,2]. It was confirmed that these striations appear due to non-linear dependence of the ionization rate on electron density caused by EEDF Maxwellization via Coulomb collisions. In the present paper, we will report progress towards simulations of other types of striations in noble gases and plasma stratification in nitrogen gas. A Fokker-Planck kinetic solver for electrons is used to simulate moving striations in DC discharges of noble gases associated with non-local electron kinetics. A fluid plasma model taking into account vibrationally excited states of molecules is used to simulate standing striations in DC discharges of nitrogen. Experimental studies are conducted to guide the computational work and validate the developed models. [1] R. R. Arslanbekov and V I. Kolobov, Advances in simulations of moving striations in DC discharges of noble gases, Phys. Plasmas 26, 104501 (2019) [2] V. I. Kolobov, R. R. Arslanbekov, D. Levko and V. A. Godyak, Plasma stratification in radio-frequency discharges in argon gas, J. Phys. D: Appl. Phys. 53 (2020) 25LT01 [Preview Abstract] |
|
RW2.00003: Experimental studies of electronegative plasma in a DC-discharge device (EPaX) designed to study internal sheaths and boundary sheath formation Lena Belvin, Peixuan Li, Noah Hershkowitz, Greg Severn Theory and computational physics studies of electronegative discharges have been intense and ongoing for several decades driven in part by the myriad applications of plasma processes in industry, but also by open questions in the physics of electronegative plasma. A focused set of benchmarking experiments testing sheath formation in electronegative plasma involving direct measurements of parameter distributions is still lacking. A DC-discharge device is nearing completion to begin those tests. The plan is to commission the device in Argon, then Argon-Oxygen, and then Argon-Iodine discharges. The first discharges are planned for Summer of 2020. Progress and results will be presented. [Preview Abstract] |
|
RW2.00004: Deconvolving Kr II laser-induced fluoresence signals for a test of Bohm's Criterion near negatively biased grid in a single ion species Kr plasma Cooper Kent, Pexuan Li, Noah Hershkowitz, Greg Severn Recent experiments of sheath formation in multiple ion species electropositive plasma have shown that ions generally do not reach the sheath edge traveling at their individual Bohm speeds. However, it is still a widely held view, and modeling assumption, that they do. The experiments in multiple ion species electropositive plasma were pursued in order to perform the first test of the generalized Bohm Criterion for three ion species plasma. The goal can be reached if we perform a deconvolution of the Kr II laser-induced fluorescence (LIF) signals, since one of the three ion species experiments used Kr II ions. But Kr II ions have significant isotope shifts and hyperfine structure, hence the need for deconvolution. Here we demonstrate and discuss one method for deconvolution, Tikhonov Regularization, using data sets from a single ion species Kr plasma with a nominal electron temperature and densities are $T_e \sim \: 3.5 eV$, and $ n_e \sim 3 \times 10^9 cm^{-3}$, respectively. and eV. The sheath was set up in the neighborhood of a negatively biased grid. Results are discussed. [Preview Abstract] |
|
RW2.00005: 2-Dimensional, Second-Harmonic, Dispersion Interferometer for Plasma-Density Imaging Frank J Wessel, Fernando Brandi Conventional optical interferometers, used for plasma-density measurements, are typically robustly mounted, two-arm, high-cost installations. The Second-Harmonic Dispersion Interferometer (SHDI) is an exception, utilizing a common path, single-laser source frequency doubled before, and after, the sample, which allows the dispersive-phase shift of the SH beams to be measured in a simple, low-cost system. Present SHDI's provide a 1-D (line-of-sight) measurement, usually configured with a CW Nd:YAG, or CO$_2$ laser. We compared the performance of these SHDI's to that of a conventional $\mu$-wave interferometer, finding the Nd:YAG to be the most stable and least complex system design.$\footnote{F. Brandi, F.J.Wessel, C.Lohff, J.R.Duff, Z.O.Haralson, Expt. Study of SHDI's for Plasma Density Measurements, Applied Optics, to appear.}$ Recently, we upgraded the SHDI for 2-Dimensional, time-resolved imaging, using a pulsed Nd:YAG laser, beam-expansion optics, digital cameras, and image-processing s/w, providing: $>$10 mRad phase change, 100 $\mu$m resolution, 1 ns sampling time, and 100 Hz frame rate, in a 0.6-cm diameter beam,$\footnote{F.Brandi and F.J.Wessel, 2D-SHDI, Optics Letters, to appear.}$ suitable for a line-integrated plasma density, $\int n \cdot dl > 10^{14}$ cm$^{-2}$. [Preview Abstract] |
|
RW2.00006: Inference of degree of dissociation for weakly collisional DC hydrogen plasmas with collisional-radiative models Bin Ahn, Yegeon Lim, Youngchul Ghim An analysis technique to infer a degree of dissociation(DOD) of weekly collisional DC hydrogen plasmas is developed and examined with an experiment. The collisional-radiative models for hydrogen atom and molecule are newly constructed and modified so that they can handle bi-Maxwellian electron energy distribution and radiation trapping effect, plus the Fulcher-alpha transition analysis for gas temperature and ground vibrational temperature from ro-vibrational distribution of excited molecules. Multiple steps are involved to produce calculated state distributions with experimentally measured parameters, and they are compared with measured spectra to infer the most reasonable DOD. To examine and verify the analysis technique, hydrogen plasmas are generated in a large cylindrical chamber, MAXIMUS, with a W filament cathode, and the gas pressure is scanned from 3 to 6mTorr. Various diagnostics including the optical absorption {\&} emission spectroscopy and the Langmuir probe measurement are used to obtain spectra and electron parameters. With the analysis technique, the DODs for the generated plasmas are inferred to be around 1{\%}, and increase with the gas pressure. [Preview Abstract] |
|
RW2.00007: Diagnostics of Expansion Tube Flows by Multi-pass Laser Absorption Spectroscopy Ryuji Kobayashi, Makoto Matsui, Kazuhiko Yamada Although expansion tubes have been used to simulate an ultrafast re-entry environment, the flow characteristics have not been completely understood. Our group has applied diode laser absorption spectroscopy (DLAS) to expansion tube flows. In our previous study, we diagnosed an expansion tubes flows in Institute of Space and Astronautical Science in JAXA using molecular oxygen line of 763.43 nm. The maximum fractional absorption was 0.6 {\%}, which is comparable with that of the atmosphere outside the chamber. Then, Herriott type multi-pass system was developed to enhance the sensitivity of DLAS by increase the absorption length. In this study, the sensitivity was increased using a Herriott type multi-pass cell. As a result, in ISAS expansion tube, the sensitivity is 43 times and temperature of test flow is 4400\textasciitilde 6000 K, but no sensitivity until the degree of dissociation is identified. [Preview Abstract] |
|
RW2.00008: Towards electric field measurements in liquid water~by electro-optic Kerr effect Tomas Hoder, Petr Hoffer, Vaclav Prukner, Milan Simek The fundamental understanding of the electrical discharges in liquid water, if initiated by nanosecond pulses with high voltage amplitudes, is still missing. In order to get detailed insight into the processes preceding the full discharge development and to support the theoretical models, the knowledge of the local electric field strength is important. We present our first results towards the electric field determination in liquid water using electro-optic Kerr effect with sub-nanosecond and sub-millimetre resolution. The developed novel methodology is applied at experimental conditions without discharge generation and its reliability and sensitivity are evaluated. [Preview Abstract] |
|
RW2.00009: On the high frequency floating harmonic method in inductively coupled plasmas Beom-Jun Seo, Kyung-Hyun Kim, Chin-Wook Chung In the conventional floating harmonic method, the sinusoidal voltage of which frequency is kHz were applied to the probe sheath. In this work, the floating harmonic method using sinusoidal waveform at 1 MHz is proposed to measure plasma parameters such as the plasma density and electron temperature with high-time resolution. In the high frequency (1 MHz) floating harmonic method, we applied a Child-Langmuir sheath model to consider a capacitance of the probe sheath. The plasma parameters obtained from the high frequency floating harmonic method are in good agreement with measurements from the electron energy distribution function. [Preview Abstract] |
|
RW2.00010: Particle-in-Cell Simulations of the Alpha and Gamma Modes in Collisional Nitrogen Capacitive Discharges Emi Kawamura, Michael Lieberman, Allan Lichtenberg, Pascal Chabert We perform 1D particle-in-cell (PIC) simulations to study the $\alpha$ and $\gamma$ modes in an intermediate pressure (0.6 and 6 Torr), 2.5 cm gap capacitive nitrogen discharge driven at 13.56 MHz with current density amplitudes $J_0$=10 to 75 A/m$^2$. As in a previous study of a comparable argon discharge,[Kawamura et al, JVST A {\bf 38}, 023003 (2020)], the nitrogen discharge can be described by a ``passive bulk'' model in which the ionization is negligible in the central bulk region and is due solely to electron sheath heating. However, unlike the argon discharge, the nitrogen discharge undergoes an $\alpha$-$\gamma$ transition in the applied $J_0$ range due to secondary electron emission, characterized by an increase in density and a decrease in sheath widths. We introduce a theoretical $J_0$-$V_1$ transition curve, where $V_1$ is the sheath voltage amplitude at 13.56 MHz, giving the $\alpha$-$\gamma$ transition. We compare the PIC results in the $\alpha$-mode to the passive bulk model, and, in the $\gamma$-mode with the expected $J_0$-$V_1$ curve. We find reasonable agreement with the simulations in both the $\alpha$~and~$\gamma$ regimes, and the $\alpha$-$\gamma$ transition is reasonably well predicted by the model. [Preview Abstract] |
|
RW2.00011: One Dimensional Model of a Planar Dielectric Barrier Discharge in Air Bahram Mahdavipour, Sebastian Dahle, Jens Oberrath Dielectric-barrier discharges (DBD) are devices which were first invented to generate ozone. Today, DBDs are being used in several applications such as surface modification, plasma chemical vapor deposition, excitation of CO$_{\mathrm{2}}$ lasers, excimer lamps, plasma display panels, pollution control, gas processing, and air cleaning. Due to the complexity of chemical and physical processes involved, multidimensional fluid simulations of DBDs in air at atmospheric pressure are very time-consuming. To reduce the simulation time, a zero-dimensional (0D) simulation can be used to reduce this chemical complexity to just 50 species and 600 reactions. However, the driving frequency, the species density, and the electron temperature as a function of space are not considered in such a 0D simulation. Taking at least the spatial behavior in one direction (1D) into account raises the question if the same reduced chemical model can be applied. Thus 1D simulations with reduced chemical reactions are compared to 0D simulations in PLASIMO. The behavior of parameters like electron temperature and densities of electrons, ions, and neutral species are studied to validate the 1D simulations. [Preview Abstract] |
|
RW2.00012: Comparison of lumped element model and particle in cell simulation for radio frequency magnetron discharges Dennis Engel, Moritz Oberberg, Birk Berger, Christian Woelfel, Jan Lunze, Peter Awakowicz, Julian Schulze, Denis Eremin, Ralf Peter Brinkmann Radio frequency magnetron sputtering allows to deposit high quality thin films. To gain basic knowledge of the plasma processes this work applies the energy-conserving 2d3v PIC/MCC code ECOPIC2S-M in rz-geometry. Parameters like the energy distribution functions, temperatures, densities and potentials can be obtained. It can be seen, that the discharge can be divided in discrete zones, the bulk, the magnetized region and the sheath regions, which can be linked via Kirchhoff relations. One insight is that the plasma can be approximated by a lumped element model. Compared to the PIC simulation the lumped element description is much faster. Nevertheless, it can be used to gain a fundamental understanding of the discharge. It was successfully used to identify the origin of the Magnetic Asymmetry Effect [1]. The length of the different zones, the current voltage behavior and the electron dynamics at the electrodes can be extracted from the PIC simulation. Those information can be used for the lumped element model. The results of the model are verified against the results of the PIC simulations.\\ $[$1$]$ M Oberberg et al., Plasma Sources Sci. Technol. 28 115021 (2019) [Preview Abstract] |
|
RW2.00013: Control of electron velocity distributions at the wafer in low pressure high voltage capacitively coupled discharges by Voltage Waveform Tailoring Li Wang, K. N\"osges, B. Berger, S. Wilczek, R. P. Brinkmann, J. Schulze, Z. Juhasz, E. Lee, T. Mussenbrock, Z. Donk\'o, A. Derzsi, P. Hartmann By Particle-In-Cell/Monte Carlo collision simulations of capacitive RF discharges operated in argon at low pressure and at high voltages, we demonstrate that tailoring the driving voltage waveform allows to generate high fluxes of energetic electrons towards one of the electrodes. These electrons impinge vertically on the wafer with velocities well above $3 \times 10^{6} \ \rm m/s$ and can, thus, penetrate deeply into high aspect ratio etch features to compensate positive surface charges inside these structures. This is achieved by generating electric field reversals during sheath collapse at the wafer by tuning the driving voltage waveform. The effects of the peak-to-peak voltage, number of harmonics, and the duty-cycle on the electron velocity distribution at the wafer are clarified for peaks-, valleys-, and square-shape-waveforms. [Preview Abstract] |
|
RW2.00014: Two-Dimensional Analysis Of Electron Transport And Heating In a Capacitively Coupled Plasma Chang Ho Kim, Hwanho Kim, Hae June Lee A lot of researches has been conducted to investigate underlying electron kinetics in a capacitvely coupled plasma (CCP) with one-dimensional (1D) particle-in-cell (PIC) simulations due to the high computational cost of multi-dimensional PIC simulations. However, 1D PIC simulations consider only the axial directional phenomena, and thus cannot investigate the effect of the radial directional electron dynamics. Examples are the sidewall effect and standing wave effects on electron heating and the nonlinear electron transport in the radial direction. In this study, we have observed the electron transport and heating mechanisms with the variations of neutral gas pressure, the driving voltage, and the electrode size using a two-dimensional PIC simulation parallelized with a graphics processing unit (GPU) [1,2]. The non-uniformity of electron density and temperature is analyzed by the balance of ion transport and ionization by electron heating. We found that the radial perturbations are inherently coupled with the electron oscillation inside of the sheath. [1] J. S. Kim, M. Y. Hur, C. H. Kim, H. J. Kim, and H. J. Lee, J. Phys. D: Appl. Phys. 51, 104004 (2018). [2] M. Y. Hur, J. S. Kim, I. C. Song, J. P. Verboncoeur, H. J. Lee, Plasma Res. Express 1, 015016 (2019). [Preview Abstract] |
|
RW2.00015: The role of electron-induced secondary electrons in low-pressure capacitively coupled oxygen plasmas Benedek Horvath, Aranka Derzsi, Zoltan Donko, Julian Schulze In this work, the role of the electron-surface processes in single-frequency (13.56~MHz) oxygen discharges is studied in the low-pressure regime ($<$~5~Pa). Two different models are used to describe the interaction of electrons with the electrodes: (i) a simple one assuming only elastic reflection of the electrons with a constant probability of 0.2 (model A) and (ii) a realistic one which takes elastic reflection, inelastic reflection and secondary electron emission into account as a function of the energy and angle of incidence of the electrons (model B). When the realistic model is used, a complex electron emission and ionization dynamics of ion-induced and electron-induced secondary electrons ($\gamma$- and $\delta$-electrons, respectively) is found at low pressures, which is similar to the dynamics recently observed in argon under the same discharge conditions. However, in oxygen, electron-induced secondary electrons also have a remarkable effect on the electronegativity of the discharge: while electronegative discharges are obtained with model A, they are found to be electropositive with the realistic model under the same discharge conditions. [Preview Abstract] |
|
RW2.00016: About the Poisson-Boltzmann equation for magnetized technological plasmas Kevin Koehn, Dennis Krueger, Ralf Peter Brinkmann Numerical simulations of magnetized plasma discharges, e.g. high power impulse magnetron sputtering (HiPIMS), generally have a high computational demand because they need to solve the 3d Poisson-Boltzmann equation and take into account that the phenomena are happening on multiple time scales. A step forward to accelerating simulations can be done if the Poisson-Boltzmann equation can be reduced to a simpler 2d case. To find valid arguments for such a simplification, we formulate a variational principle based on fundamental thermodynamic relations. The electrons are assumed to be in thermodynamic equilibrium on each magnetic field line separately (on the time scale of the electron bouncing motion) against a background of given ion density. The variational principle aims to minimize the negative entropy under the constraints of a conserved electron number on each field line and a conserved total energy. For this, so-called flux coordinates $(\psi,\theta,s)$ are introduced to describe the characteristic topology of axisymmetric magnetic fields typical for circular magnetrons. For spatially homogeneous magnetic fields, an alternative approach can be made by employing a Fourier-ansatz to find the potential $\phi$, which already reveals a lot of interesting insights. [Preview Abstract] |
|
RW2.00017: The pulsed mode of negative DC corona discharge in nitrogen and oxygen mixture gas Xing Zhang, Yulin Guo, Anbang Sun The pulsed mode in electronegative gases (Trichel pulses) has been systematically investigated for many years, in which negative ions are crucial to the formation of pulses. However, the appearance of the pulsed mode in non-electronegative gases challenges the traditional concept. In this work, the pulsed mode of negative DC corona discharge in nitrogen/oxygen mixture gases (oxygen fractions ranges from 0 to 20{\%}) is investigated with needle-plane electrodes at 100kPa. It is found that characteristics of pulsed modes of low oxygen content and high oxygen content are remarkably different, such as frequency, pulse width, waveform of the cathode voltage. The external ballast resistor and negative ion are the dominant mechanisms for the low and high oxygen content gases respectively, and these two mechanisms can be unified interpreted as an effect of impedance on the charges transfer. [Preview Abstract] |
|
RW2.00018: Hand-generated piezoelectric mechanical-to-electrical energy conversion plasma Jinyu Yang, Olivia Jaenicke, Federico Hita, Seong-kyun Im, David Go This work examines electrical characteristics of the transient spark generated by a manually-powered piezoelectric energy conversion device. Conventional methods to generate transient sparks usually require a high-voltage input. Piezoelectric crystals offer alternatives that do not require a high-voltage input and can be powered with mechanical work. Here, a piezoelectric igniter was utilized as the plasma source, and a snail cam-and-follower actuator was designed to provide repeatable mechanical actuation. Electrical analysis of the generated discharge shows that it behaves as a transient spark, discharging 0.53 mJ over about 30 ns, with consistent behavior over multiple consecutive actuations. While this specific device has a low energy conversion efficiency of 0.85{\%}, its relatively short resetting time of \textasciitilde 8 \textmu s suggests that it could be operated with mechanical input up to nearly 125 kHz. This work shows the potential that in situ pollution mitigation or plasma-enhanced combustion can be applied to off-the-grid situations by recovering waste energy of other mechanical systems. Greater promise can be achieved with mechanical systems that naturally operate at frequencies similar to the maximum achievable by the piezoelectric system. [Preview Abstract] |
|
RW2.00019: Portable APPJ-OES system for trace elements detection in liquids Gandhari Bhandari, Mounir Laroussi An atmospheric pressure plasma jet (APPJ) used as a non-thermal excitation source was incorporated with portable fiber optics spectrometer for trace elements detection. Water targets with various salt concentrations (1ppm, 50ppm, 100ppm, 1000ppm, 10000ppm and 50000ppm) added were prepared and treated with the plasma pencil. The operating conditions were: Gas: Argon with a flow rate of 10slm, 13slm, and 15slm; Voltage: 8.53 kV, Pulse width: 1 $\backslash \mu $s; Frequency: 5 kHz; Distance between nozzle and liquid surface: 9 mm. The overall light emission intensity of the plasma plume was found to increase as the concentration of salt solution increased. This is the result of the increased conductivity of the sample with increasing salt concentration in the sample. Time-resolved emission spectra were recorded at a specific wavelength for Na (590nm) and Cl (837.64nm). They showed noticeable peak intensity variation with the sample concentration. The chlorine intensity was found to increase about 1.8X at 1 ppm of salt solution, however, only modest increase in Na intensity was observed reaching about 1.4X at 10000ppm when referenced to Ar plasma without liquid target, which indicates preferred Cl excitation over Na. This case study suggests the possible use of the portable APPJ-OES analytical system to detect specific trace elements, Na and Cl in this case, in liquid targets. Our results also indicate that the APPJ-OES system can serve as an accurate real-time sensor to detect variations in sample conductivity. [Preview Abstract] |
|
RW2.00020: Flexible Plasma Jet Source for Biomedical Applications Carles Corbella Roca, Sabine Portal, Li Lin, Michael Keidar A new plasma source design that merges characteristics of capacitive dielectric barrier discharge (DBD) and cold atmospheric plasma jet (CAPJ) is presented. The DBD system consists of a porous ceramic material comprised between two planar electrodes. The supply of He flow, in combination with a sinusoidal voltage of $\approx $5 kV in amplitude and 12.5 kHz in frequency, provides a streamer that propagates beyond the DBD system. The plasma jet system can adopt different shapes with the aim of uniform surface treatment of 3D objects. Aspects like CAPJ extension, performance and lifetime of the plasma device are discussed in this paper. The composition and discharge parameters of the CAPJ are characterized by means of optical plasma diagnostics. Finally, we consider applications in plasma-based cancer surgery, as for example treatment of surgical margins. This novel source is also suitable for situations where plasma parameter adaptation to the environment (atmosphere and target surface) are required. [Preview Abstract] |
|
RW2.00021: Electron dynamics in micro atmospheric pressure radio frequency plasma jets with customized electrode materials and topologies Lena Bischoff, Ihor Korolov, Gerrit Huebner, Zoltan Donko, Yue Liu, Thomas Mussenbrock, Julian Schulze Radio frequency driven micro atmospheric pressure plasma jets (u-APPJ) are commonly used to produce non-thermal plasmas and to generate reactive species suitable for various applications, e.g. biomedicine and modification of sensitive surfaces. The optimization of a given application by controlling the generation of reactive particles is a complex problem and can be influenced by the choice of the electrode materials and topologies. We perform a systematic investigation of the electron heating dynamics in a single frequency (13.56 MHz) u-APPJ with planar and structured electrodes made of different materials (e.g. stainless steel, Al, Cu). Helium with different N$_{\mathrm{2}}$ or O$_{\mathrm{2}}$ admixtures and a broad range of peak-to-peak driving voltage amplitudes are used. Based on experiments and simulations, we demonstrate that the choice of the electrode material and topology affect the electron heating dynamics, and thus, the formation of process relevant reactive species. [Preview Abstract] |
|
RW2.00022: Fast optical and electrical measurements at a single microdischarge setup during plasma electrolytic oxidation (PEO) Anna Lena Schoene, Vera Bracht, Patrick Hermanns, Peter Awakowicz Plasma electrolytic oxidation (PEO) is a process for the passivation of lightweight metals like aluminum. During this process, short-living microdischarges occur stochastically distributed on the substrate surface. To understand the individual behaviour of these microdischarges, a single microdischarge setup with an aluminum wire anode of 1 mm diameter employed. The wire is surrounded by an isolating cladding to reduce the active metal surface to the front tip of the wire. As electrolyte, a solution of potassium hydroxide (KOH) in destilled water (1 g/l) is used. The small active surface area enables optical and electrical measurements of single microdischarges. Time-resolved shadowgraphy and fast optical measurements with a quad ICCD camera and an Echelle spectrometer are carried out for a better understanding of the development and evolution of single microdischarges. The different life time stages of the microdischarges can be observed by triggering on the microdischarge current and delaying the measurements within the microdischarge lifetime. The measurements are performed for different frequencies (100 Hz, 1 kHz, 10 kHz) as well as maximum current densities (2,5 A/cm2, 5 A/cm2). [Preview Abstract] |
|
RW2.00023: On decoupling dark and luminous phases of nanosecond discharges developing in liquid water. Milan Simek, Petr Hoffer, Vaclav Prukner, Jiri Schmidt There is no clear experimental evidence of the underlying microscopic mechanisms of micro-discharges produced by high-voltage pulses of nanosecond duration in liquid water. In this work, we examine shadowgraph images and plasma-induced emission (PIE) to decouple nearly simultaneously developing dark and luminous phases of nanosecond discharges in deionized water. We applied diagnostics with extremely high temporal and spatial resolutions to capture tiny dark filaments together with the formation of luminous discharge structures. Following the main objective of disentangling two closely coupled dark and luminous phases, we accurately determined their onsets with respect to the driving high-voltage pulse. We establish that the initial dark filaments start occurring within $\sim $3-4 ns after the onset of the high-voltage pulse, and subsequently expand at a constant velocity of $\sim $1$\cdot $10$^{\mathrm{5}}$-2$\cdot $10$^{\mathrm{5}}$ m/s, depending on the high-voltage amplitude and anode curvature. A systematic analysis of the PIE waveforms together with the associated shadowgraph images reveals that the onset of the luminous discharge phase is delayed by $\sim $600-800 ps with respect to the onset of the initial dark filaments. [Preview Abstract] |
|
RW2.00024: On UV emission developing during luminous phase of nanosecond discharges in liquid water. Milan Simek, Vaclav Prukner, Jiri Schmidt, Petr Hoffer There is no clear experimental evidence of the underlying microscopic mechanisms of micro-discharges produced by high-voltage pulses of nanosecond duration in liquid water. In this work, we examine plasma-induced emission (PIE) to reveal basic spectrometric characteristics of developing luminous phase of the discharge in the UV spectral range with temporal resolution of 100 ps. We present a viable approach for conducting well-designed and well-defined experiments for acquiring the PIE in the 200-320 nm spectral window. We reconstruct basic UV signatures through the analysis of the PIE waveforms acquired using an ultrafast photomultiplier and complemented by emission spectra acquired by the ICCD spectrometer. We establish that the UV emission produced during the luminous phase comes exclusively from luminous filaments developing in bulk liquid and is characterized by a broad peak occurring between 255-275 nm. Additionally, this study contributes to the progress of the PIE analysis and provides further insight into the basic radiative processes occurring during the luminous discharge phase in liquid water. [Preview Abstract] |
|
RW2.00025: In situ Raman microspectroscopy of liquid water in contact with a DC glow discharge in ambient atmospheric-pressure air David Pai The study of the plasma-water interfacial region is critical to gaining an understanding of how atmospheric-pressure plasmas transform water into plasma-activated water. We investigate plasma-water interaction using in-situ Raman microspectroscopy, both at the plasma-water interface and in depth, with a spatial resolution as high as several tens of microns. The plasma reactor of choice is a DC glow generated in ambient air using a pin electrode placed above an optical cell filled with deionized water. The Raman spectra tracked in real time include the --OH stretch, bend, and librational bands of water. In particular, the --OH stretch band experiences increasing intensity of the fundamental frequency distribution around 3400 -- 3500 cm$^{\mathrm{-1}}$, which is weakly coupled to other hydrogen bonds. The peak around 3200 -- 3300 cm$^{\mathrm{-1}}$, resulting from intermolecular coupling and strong hydrogen bonding, experiences decreasing intensity. We will discuss both rapid and gradual changes to the Raman spectra over the course of plasma treatment, as well as the reversibility of these changes once the plasma is switched off. The effect of depth below the plasma-water interface will also be discussed: the changes to the Raman spectra become more pronounced as the detection volume approaches the interface. [Preview Abstract] |
|
RW2.00026: Experimental Confirmation of Transport Model for Solvated Electrons in a Plasma Electrochemical System Daniel Martin, David Bartels, Paul Rumbach, David Go In this work, the transport of the plasma injected solvated electron is studied using total internal reflection absorption spectroscopy (TIRAS). We previously measured the absorption spectrum for plasma injected electrons at the plasma-liquid interface, which aligns with results produced using nanosecond pulse radiolysis. A theoretical model is used to predict the reaction-diffusive penetration of these electrons, and recent work predicted a 1/3 exponential scaling of TIRAS intensity with the plasma current density. In this work we perform TIRAS measurements while controlling plasma current density, with the objective of confirming this predicted 1/3 scaling. By doing so, we find that at higher current densities a scaling of approximately 1/3 power is observed. However, the scaling is linear at lower concentrations, which we show is due to the transient response of the experiment operating in a modulated mode. Having been demonstrated, this scaling law can predict approximate limits of penetration and interfacial concentration for solvated electrons and hydroxyl radicals, allowing for the enhanced tailoring of a variety of plasma-liquid systems to their applications. [Preview Abstract] |
|
RW2.00027: Effect of metal catalyst loading on surface ionization waves in packed bed dielectric barrier discharge Zaka-ul-Islam Mujahid, Mukul Sharma, Abdullah Alfaifi, Julian Schulze Metallic catalysts are often added on the surface of dielectric beads in a packed bed dielectric barrier discharge to improve the performance. The improved performance is possibly linked with the synergy between the plasma and catalyst; however, such synergy still needs to be understood fundamentally. The previous work showed that plasma is generated in a packed bed reactor due to the combination of filamentary microdischarges (F-MD) in volume, surface microdischarges (S-MD) at the contact points and surface ionization waves (SIW) over the surface [1]. In this work, we have investigated how the metal catalyst loading position on the dielectric surface affects the discharge mechanisms especially the surface ionization waves. The results showed that the metal catalyst loading can change the initial breakdown position and surface ionization waves can be enhanced or suppressed depending on the catalyst loading position. The change in discharge behavior could be linked to the enhancement of the electric field emission and change in the electric field distribution. [1] Z. Mujahid, J Kruszelnicki, A Hala and MJ Kushner, Chemical Engineering Journal, 382,~ p. 123038. (2020) -/a [Preview Abstract] |
|
RW2.00028: Development of an Ozone-based Treatment System for Reuse of Personal Protective Equipment (PPE) John Lassalle, Md Abdullah Hil Baky, Min Huang, Kavita Rathore, Matthew Burnette, David Staack Limited availability of PPE can pose hazards to health care and other essential personnel until an effective vaccine for COVID-19 is developed. Ozone has been proven effective for sterilization, and several plasma-based systems are capable of generating ozone and other reactive species. An ozone-based mobile treatment system for sterilization of personal protective equipment (PPE) was developed. Various ozone generation schemes were considered, including corona arrays and dielectric barrier discharges (DBDs). Effects of treatment on material properties, especially mechanical integrity, filtration effectiveness, and resistance to liquid penetration, of PPE and relevant materials were evaluated after treatment. Treated PPE included respirators and hospital gowns. Steady-state ozone concentrations from 1 to 30 ppm were targeted, and total ozone exposure varied from a few ppm-min to several hundred ppm-min. Bacterial cultures were used to evaluate pathogen reduction. Experimental parameters included humidity and temperature in the system, convection, and ozone generator power. Other aspects of system design, such as safety considerations and material compatibility, are discussed. [Preview Abstract] |
|
RW2.00029: Effect of Helium Mixing on Temperature distribution of Krypton Laser Sustained Plasma Kazuyoshi Ishikawa, Ryoki Niwa, Kota Okamoto, Makoto Matsui Laser propulsion is a novel space transportation system that obtains thrust through the laser sustained plasma (LSP) generated by the focused laser beam. This system is expected to have a higher specific impulse than arc jet system and long lifetime because of no electrode erosion. Considering the adaption of LSP to the space transportation system, it is necessary to generate LSP using a diode laser which has high energy conversion efficiency. In our previous study, the diode laser sustained plasma using the mixing gas was successfully generated. The mixing gas consists of krypton which is relatively lower ionized energy and helium which makes specific impulse high because it is the lower atomic weight. However, in order to evaluate the performance as a space transportation system, it must obtain the temperature distribution of LSP. In this study, we investigated and report the effect of helium mixing on temperature distribution of krypton laser sustained plasma. [Preview Abstract] |
|
RW2.00030: Physical Differences Between Xenon and Krypton Operation on a Magnetically-Shielded Hall Thruster Leanne Su, Benjamin Jorns Hall Effect thrusters (HETs) are an electric propulsion device with high thrust, moderate specific impulse, and decades of in-space flight heritage. Magnetic shielding has extended lifetimes on HETs, enabling longer missions which necessitate higher propellant throughputs. The cost of traditional propellant for HETs, Xe, is prohibitively high. Krypton offers a cheaper alternative at lower thrust and higher specific impulse. It is necessary to understand how and why the performance of magnetically-shielded (MS) HETs changes between these species at the same power. A 9-kW MS HET was operated in a vacuum facility on Xe and Kr. The anode efficiencies and phenomenological efficiencies were measured with a thrust stand and a probe suite. The results indicate that Kr performs worse than Xe on a shielded thruster by a larger margin than seen on unshielded ones. This disparity is attributed to decreases in the mass and current utilization efficiencies for Kr. Potential theories for this include a change in the radial electron temperature channel profile and increased electron mobility. Simulations of a MS HET on Kr are used to substantiate these theories. The results of this study illuminate trends in Xe and Kr efficiencies on a MS HET and explore their underlying physical differences. [Preview Abstract] |
|
RW2.00031: Thruster-spoke dynamics interpreted in terms of periodic nonlinear driven phenomena Mark Koepke Signatures of entrainment, frequency and wavenumber pulling, excitation thresholds, and particle transport, associated with observed patterns of self-organizing dynamics of instabilities in E\texttimes B plasma discharges, are being investigated in the archived data from the CHT experimental device at PPPL that had been temporarily moth-balled. The objective is to explain the spatio-temporal plasma behavior of the ``spokes'' that have been observed in modulated breathing oscillations in a cylindrical Hall-thruster plasma discharges using a combination of forced van der Pol oscillator equations, electrostatic gradient drift instabilities, the modified Simon-Hoh instability, and the influence of ionization instability. These signatures, yet to be fully explained, resemble those associated with limit-cycle behavior thoroughly characterized in other discharge plasmas and electronic nonlinear-oscillator circuits, so the anticipated goal is to validate an improved model of spoke frequency scaling with the pressure and magnetic field for Xenon and other gases. The long-range goal is to apply this validated model to other Hall thrusters and to a possible post-restoration experimental phase of the experimental device. [Preview Abstract] |
|
RW2.00032: Fluid Closure Model for Anomalous Electron Transport in a Low Temperature Crossed Field Device Benjamin Jorns The existence of anomalous, or non-classical, electron transport in Hall effect thrusters poses a major challenge for the modeling of these devices. While most engineering simulations for these thrusters are fluid-based, the anomalous electron transport is believed to be related to the kinetically-driven onset of drift-driven turbulence. This presents a problem for how to self-consistently and predictively model the anomalous transport in a fluid framework. The approach presented here is to leverage a two-equation model, analogous to the k-e closures from classical fluid modeling. The evolution of the average energy of the turbulence and the rate of dissipation in the thruster are both modeled with one dimensional PDEs. These models are then calibrated against experimental measurements from a 9-kW class Hall thruster. The calibrated model is inserted into a 2D fluid model to yield predictions for thruster plasma properties and performance. These results are discussed in the context of extensibility of the closure model to other thruster operating conditions and geometries. [Preview Abstract] |
|
RW2.00033: Ultrasonic Assisted Fabrication of Metal Nanoparticles by Laser Ablation in Liquid Xin Hu, Mardiansyah Mardis, Wahyu Diono, Noriharu Takada, Hideki Kanda, Motonobu Goto Laser ablation in liquid (LAL) is known to be a promising method for synthesizing metal nanoparticles. Here, gold and silver nanoparticles were fabricated by ultrasonic-assisted LAL. Gold and silver plates were ablated by using a Nd: YAG laser with a wavelength of 532 nm and energy of 26.4 J/cm2 in distilled water in the presence and absence of the ultrasonic field. The fabricated nanoparticles colloidal solution was analyzed with UV-vis spectrometer, transmission electron microscope (TEM) with energy dispersive X-ray spectroscopy (EDS) and zeta potential measurement. The craters on the silver plates were analyzed by scanning transmission electron microscope (SEM), laser microscope and MATLAB to observe the morphology and calculate the volume to obtain the concentration of fabricated nanoparticles solution. The optical emission was observed to study the characteristics of the laser. The results showed that ultrasonic-assisted LAL has considerable potential in fabricating superior metal nanoparticles. [Preview Abstract] |
|
RW2.00034: Wave generation in a rare gas low-voltage beam discharge. Rustem Matveev, Vladimir Sukhomlinov, Alexander Mustafaev, Nikolay Timofeev The work is devoted to the theoretical study of the instability of a low-voltage beam discharge (LVBD) in rare gases for the Knudsen numbers of the order of 1, when it is necessary to use the kinetic approach to describe the processes occurring in the LVBD. The discharge in He is used as an example. Based on the solution to the system of kinetic equations for the distribution functions of the beam and plasma electrons and the Poisson equation, the instability of the LVBD is studied analytically and numerically taking into account the attenuation of the electron beam due to electron - atom collisions when the electron mean free path is of the order of the inter-electrode distance. It was found that at the loss of stability in the conditions in question the amplification of several waves with different growth rates is possible, and the waves propagate at different speeds. With a linear decrease in the beam intensity, two waves are generated; named ``n'' and ``p''. The wave ``p'' having a smaller gain increment propagates at a higher speed. The indicated phenomenon is characteristic not only for the LVBD in rare gases, but for any system of a ``cold'' high-energy electron beam - plasma under conditions when it is necessary to take into account collisions between beam electrons and atoms. [Preview Abstract] |
|
RW2.00035: Electron power absorption through the sheath heating in low pressure microwave surface wave discharges Denis Eremin Plasma discharges driven by surface waves in the microwave range of frequencies, capable of attaining overcritical plasma densities, have a large number of applications in plasma aided technologies. The electron power absorption mechanism bears great significance since it affects the plasma generation efficiency. It is commonly assumed that the dominant electron energization mechanism in such discharges operated at relatively low neutral gas pressures is the so-called "plasma resonance", which occurs at the location where the plasma frequency matches the driving frequency and where the electric field is expected to increase dramatically, leading to electron acceleration in the direction of decreasing plasma density. However, by modeling an example of such a discharge based on the plasma-line setup with the implicit energy-conserving electromagnetic 2d3v PIC/MCC code ECOPIC2M, the dominant electron heating mechanism is shown to be similar to the sheath heating mechanism observed in rf-driven discharges, where moving sheath "pushes" electrons during the sheath expansion. The direction of electron acceleration, predicted by such a mechanism and observed in the PIC simulations, is toward the bulk plasma, in contrast to the direction anticipated from the plasma resonance. [Preview Abstract] |
|
RW2.00036: Similarity of Radio-Frequency Discharges in Nonlocal Regimes. Yangyang Fu, Bocong Zheng, Peng Zhang, Qi Hua Fan, John P. Verboncoeur, Xinxin Wang We report the fully kinetic results from particle-in-cell/Monte Carlo collision simulations that unambiguously demonstrate the similarity of radio-frequency discharges in nonlocal regimes, where the electron energy relaxation length is much larger than the gap dimension. Similar discharges are obtained in various scaled gaps when the gas pressure, gap dimension, and applied voltage frequency are simultaneously tuned through a scaling factor. The scaling relations of fundamental discharge parameters are illustrated, and the temporal electron kinetics are shown to have invariance in similar discharges, which validates the similarity laws in nonlocal kinetic regimes. [Preview Abstract] |
|
RW2.00037: Numerical distortion removal method of Langmuir probe I-V curve in RF plasma KyungHwan You, Kyung-Hyun Kim, Chin-Wook Chung In the Langmuir probe method, RF plasma potential oscillation can cause distortion of the I-V curve, so the RF voltage applied to the probe sheath must be minimized for accurate measurement. In a dual or triple RF plasma, RF choke filter must compensate not only harmonic components but also intermodulation components. However, it is difficult to design an RF choke filter to compensate for such frequency components. In this study, we suggest a method for numerically removing the distortion. The distorted I-V curve was obtained from the probe without the RF choke filter and the RF perturbation was measured by the auxiliary probe. At this time, a normal I-V curve can be obtained by the numerical method using the measured RF perturbation and the distorted I-V curve. The I-V curve through this method and the I-V curve from RF compensated Langmuir probe were compared. It was confirmed that the I-V curve and electron temperature obtained by the above method are in good agreement with that of Langmuir probe with RF choke filter. [Preview Abstract] |
|
RW2.00038: Development and characterization of hollow cathode plasma source for LIF-dip spectroscopy Jenny Smith, Christopher Durot, John Foster A pulsed plasma hollow cathode source has been developed for the purpose of producing excited states for validation of a laser-induced fluorescence (LIF) dip spectroscopy diagnostic. Time variation in plasma conditions as well as plasma repeatability was characterized using optical emission spectroscopy and a triple Langmuir probe. Experiments were carried out in air, in argon and in nitrogen. The time decay constant for density and temperature was measured. The decay constant of excited states of interest are also characterized as a function of time. Of particular interest is the flow of excited species into the actual test cell. A biased grid is used to minimize the flow of plasma species into the test cell. The effectiveness of this biased grid approach is also assessed. [Preview Abstract] |
|
RW2.00039: Modeling Stark Effect on Rydberg States of Argon to Support Laser-Induced Fluorescence Spectroscopy Christopher Durot, John Foster Sensitive spectroscopic measurements of electric field are possible based on the stark effect of Rydberg states. The analysis of spectra can be complicated by splitting of many line components that are nearly degenerate without the perturbation of an electric field and by many other transitions nearby. Modeling Stark splitting would help to select level schemes that are convenient for measurements and help in interpreting experimental spectra. We are implementing a Stark effect model for noble gas Rydberg states using jK coupling and hydrogenic wavefunctions. We apply the model first to a level scheme from literature to validate our implementation and second to different transitions to predict spectra and develop a clearer plan for the level scheme of the LIF-dip diagnostic we are also developing. [Preview Abstract] |
|
RW2.00040: Magnetic flux coordinates for axisymmetric magnetically enhanced discharges Dennis Krueger, Ralf Peter Brinkmann For describing the intrinsically complicated dynamics of a charged particle in the presence of a magnetic field, magnetic flux coordinates are a well established framework, being successfully used in fusion research and astrophysics. For the application in technological plasmas, however, important amendments have to be made. Especially the incorporation of domain boundaries is a crucial point because magnetic field lines might intentionally intersect with those. Therefore, in this work we present a system of field aligned coordinates ($\psi, \theta, s$) considering this peculiar requirement. At the present stage, it is especially suited for an axisymmetric magnetic field setup, which can be found e.g. in circular magnetrons and consists of the magnetic flux value $\psi$, the azimuth angle $\theta$, and the arc length parameter $s$. The first two select a specific field line and the last one describes a certain location onto it. As a first application of the extended framework, we present confinement times of highly energetic electrons within a high power impulse magnetron sputtering (HiPIMS) discharge. The solution of an eigenvalue problem based on a linear kinetic model is compared to insights obtained with a 3d single particle MCC (Monte Carlo Collision) simulation. [Preview Abstract] |
|
RW2.00041: Electron heating dynamics in magnetically-enhanced Capacitively Coupled Plasmas Birk Berger, Moritz Oberberg, Dennis Engel, Christian Woelfel, Denis Eremin, Jan Lunze, Ralf Peter Brinkmann, Peter Awakowicz, Julian Schulze Capacitively coupled radio-frequency plasmas are frequently used in the industry to facilitate the processing of surfaces by e.g. etching and/or deposition. Adding a magnetron-like magnetic field configuration to the powered electrode is a well-established method in order to increase the heavy particle flux to the target. However, the understanding of fundamental physical processes in these discharges is still an open question in the plasma community. In order to overcome this drawback, the presented work investigates the electron power absorption dynamics of RF magnetron plasmas by phase resolved optical emission spectroscopy. Varying the neutral gas pressure, the magnetic flux density, as well as the applied voltage shows a significant impact on the excitation dynamics of energetic electrons. For low magnetic flux densities and a low neutral gas pressure, a beam-like behavior of the electrons can be observed, while stronger magnetic fields lead to the confinement of the electrons close the target. Under certain conditions an electric field reversal close to the powered electrode can be observed due to the required compensation of the mean ion flux to the electrode by the electron flux over one RF period. [Preview Abstract] |
|
RW2.00042: RF multi-jet, atmospheric plasma for metal substrate cleaning Cezar Gaman, Nishant Sirse, Stephen Daniels, Miles Turner During the manufacturing process of orthopaedic implants, the cleaning step plays an essential role to achieve the biocompatibility required for the implant to be successful. We propose a new radio frequency multi-jet atmospheric pressure, low temperature plasma process for removal of organic residues from the implant's surfaces. The advantage of this method over the ones currently in practice is the lack of remains from the added chemical cleaning agents. The plasma jets are produced using a 13.56 MHz matched RF applied voltage in a controlled He/O2/At gas mixture. The polished and rough test substrates are purposely ``spiked'' with contaminants which get in the contact with the metal surface during the manufacturing process. The cleaning efficacity is measured using FTIR and XPS. This research was conducted with the financial support of Science Foundation Ireland (SFI) under grant number 12/RC/2278 and 17/SP/4721, and co-funded by the European Regional Development Fund and Science Foundation Ireland under Ireland's European Structural and Investment Fund. This research has been co-funded by the 3D Printing Centre of Excellence, Johnson {\&} Johnson Services Inc., and DePuy Synthes. [Preview Abstract] |
|
RW2.00043: Three-Dimensional Measurement of Electron Temperature and Density in a Split Ring Resonator Microplasma using Langmuir Probes Neil Laya, Andrew Walsten, Gabe Xu The Split Ring Resonator (SRR) is a micro-plasma generation device originally developed for use in the metamaterial field yet poses as a promising plasma source in ion thrusters. Research done previously has determined optimal design characteristics and the viability of the SRR in ion thrusters. So far, an SRR has been made and tested to find its optimal performance frequency. In order to further integrate the SRR into a miniature ion thruster, a three-dimensional analysis will be performed. This three-dimensional analysis will map both the plasma density and electron temperature of an argon micro plasma. The analysis will be performed using an asymmetric double Langmuir probe to find current-voltage curves at each individual point. To calculate plasma density and electron temperature, the Four Free Fitting Parameters method will be used to fit the data and the Druyvesteyn method to perform the calculations. Eventually, a three dimensional analysis will determine the optimal grid placement for a miniature ion thruster to be built. [Preview Abstract] |
|
RW2.00044: Breakdown process of dual-frequency Capacitively Coupled Plasma: A collective simulation Hao Wu, Youyou Zhou, Jiamao Gao, Yanli Peng, Zhijiang Wang, Wei Jiang Study on breakdown can not only reveal the evolution of electrical feature of plasma, but also verify the theory of gas discharge. Almost all plasma sources have to undergo breakdown process, however, due to the extremely short time interval, it is difficult for experiment to observe this evolution process. One-dimensional direct implicit Particle-In-Cell/Monte-Carlo Collision (PIC/MCC) program is used to study the breakdown process of Capacitively Coupled Plasma (CCP) driven by dual-frequency and coupled with external circuit. The result shows that the breakdown process can be divided into the pre-breakdown and post-breakdown process clearly, and it can be distinguished by the formation of sheath. In the pre-breakdown stage, plasma density grows exponentially, however, because of low initial density, electric field can penetrate the whole discharge area without any blocking, which produce plenty of high-energy electrons, and many of them can bombard the electrode plate to generate secondary electrons. There is a interim phase between the pre-breakdown and post-breakdown, during which both the electron generation rate and heating power of plasma reach the maximum value and the external circuit changes from a linear system to nonlinear system. In post-breakdown stage, the density and temperature of plasma gradually stabilize. CCP device can be approximated as a series of nonlinear capacitance, resistance and "inductance", and capacitance dominates the characteristics of CCP and the changing capacitance is the main cause of harmonics. [Preview Abstract] |
Not Participating |
RW2.00045: Ion-acoustic surface waves propagating in a turbulent semi-bounded plasma with quantum recoil effect Young-Dae Jung, Myoung-Jae Lee The dispersion relation for the low-frequency ion-acoustic surface waves propagating in a semi-bounded turbulent plasma including the effect of quantum recoils is derived based on the kinetic dielectric permittivity of a quantum plasma. The specular reflection boundary condition for the interface of plasma-vacuum is employed and the transverse truncation method is used to derive the appropriate dispersive property of the surface mode of ion-acoustic waves for the degenerate and non-degenerate electrons. We find that the damping rate and the wave frequency are enhanced by the quantum recoil effect for both non-degenerate and degenerate cases. The quantum recoil effect on the wave propagation is significantly reduced as the wave number becomes small. We find that the diffusional dissipation in the turbulent plasma becomes more important than the quantum recoil for the wave propagation as the wave number is reduced. [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