Article
Physics, Fluids & Plasmas
I. A. Aponte, B. Esser, James C. Dickens, John J. Mankowski, Andreas A. Neuber
Summary: The study on Unipolar (DC) and radio frequency (RF) corona at 3.3 MHz in atmospheric air at room temperature revealed that needles with smaller included angles had lower onset voltages. There was no distinguishable difference in onset voltages between pure tungsten and 2% lanthanated tungsten needles, indicating that adding lanthanum to tungsten had a negligible impact on onset voltages at 3.3 MHz frequencies for electrodes at room temperature.
PHYSICS OF PLASMAS
(2021)
Article
Engineering, Aerospace
Pau Bas-Calopa, Jordi-Roger Riba, Manuel Moreno-Eguilaz
Summary: The combination of low-pressure environment and aircraft electrification increases the risk of electrical discharges. Most studies only consider static pressure conditions, but aircraft systems experience dynamic pressure conditions during climb and descent. This paper analyzes the effect of dynamic pressure during climb on corona inception voltage and finds that it has no significant impact under typical climb conditions.
Article
Chemistry, Analytical
Jordi-Roger Riba, Pau Bas-Calopa
Summary: This paper evaluates and compares the sensitivity of two methods for detecting and locating corona discharges, based on a DSLR camera and a portable wideband sonic camera. The results show that the sonic camera can detect and locate corona discharges quickly, simply, and sensitively, even in daylight conditions and at a distance of several meters from the discharge source.
Article
Physics, Fluids & Plasmas
Dmitrii L. Kuznetsov, Viktor V. Uvarin, Igor E. Filatov
Summary: Investigations were conducted on methane conversion in mixtures CH4-CO2 and CH4-O-2 under different conditions processed by pulsed nanosecond discharges. The energy efficiency of carbon dioxide conversion of methane depended on the power of the discharge pulse. The most efficient dry reforming of methane occurred in spark discharge with pulse duration of 15 ns at a pressure of 1 atm.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2021)
Article
Physics, Fluids & Plasmas
N. Yu Babaeva, G. Naidis
Summary: The study focuses on CO2 molecule conversion through electron impact dissociation, estimating efficiency using various dissociation cross sections. The best fit with experimental data for corona and dielectric-barrier discharges is found using Phelps' cross section for excitation of electronic states with an energy threshold of 10.5 eV under specific electric field conditions.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Aerospace
Jordi-Roger Riba
Summary: Due to the increase in electrical power demand, future electric and all-electric aircraft will operate at higher voltage levels. Selecting suitable optical sensors to detect electrical discharges at an early stage is crucial for aircraft safety.
Article
Physics, Applied
Eduardo Morais, Annemie Bogaerts
Summary: A chemical kinetics model was developed to study the gas-phase dynamics of H-2 production in nanosecond-pulsed CH4 plasmas. The model showed reasonable agreement with experimental results, indicating a 30% conversion rate of CH4 with C2H2 and H-2 as major products. The study also revealed the important role of vibrationally excited CH4 and H-2 in transferring energy from the plasma to gas-phase heating, and found that H-2 synthesis is not affected by applied pressure.
PLASMA PROCESSES AND POLYMERS
(2023)
Article
Geosciences, Multidisciplinary
Krystallia Dimitriadou, Olivier Chanrion, Torsten Neubert, Alain Protat, Valentin Louf, Matthias Heumesser, Lasse Husbjerg, Christoph Kohn, Nikolai Ostgaard, Victor Reglero
Summary: This study reports observations of corona discharges at the uppermost region of clouds, showing that they are present in various convective environments and may be common in convective surges.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
S. Soler, F. J. Gordillo-Vazquez, F. J. Perez-Invernon, A. Luque, D. Li, T. Neubert, O. Chanrion, V Reglero, J. Navarro-Gonzalez, N. Ostgaard
Summary: BLUEs are transient corona discharges in thunderclouds with strong 337.0 nm light flashes. A total of about 11 BLUEs occur globally every second, with a nighttime peak in the northwest region of Colombia and a global peak in the boreal summer-autumn. The geographical distribution of nighttime BLUEs shows three main regions: the Americas, Europe/Africa, and Asia/Australia.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Construction & Building Technology
Yibin Lu, Tiantian Wang, Xiaohui Xiong, Hengkui Li, Fangcheng Shi, Chen Jiang
Summary: This study proposes a surrogate model based on a porous medium to simulate the operation of high-static pressure fans (HSPFs) and analyze the dynamic sealing capability. The results show that the HSPF_on mode effectively restrains pressure transmission and improving fan performance enhances the dynamic airtightness of HSPF. In addition, a new method for investigating the dynamic airtightness of HSPFs is provided in this study.
BUILDING AND ENVIRONMENT
(2024)
Article
Physics, Fluids & Plasmas
G. Naidis, N. Yu Babaeva
Summary: A model of repetitively pulsed low-pressure CO2 discharges is developed, and plasma characteristics during the pulses and in the afterglow periods, as well as the CO2 conversion factor, are calculated. The computed results are in agreement with available experimental data.
PHYSICS OF PLASMAS
(2022)
Article
Physics, Fluids & Plasmas
Tiancheng Zhang, Huaguang Bao, Dazhi Ding, Rushan Chen
Summary: In this paper, a modified multi-physics method for transient analysis of high-power microwaves (HPM) gas breakdown is proposed. Numerical simulations demonstrate the accuracy of the proposed method, and an external DC magnetic field can effectively delay HPM breakdown and control the phase shift of electromagnetic waves.
PHYSICS OF PLASMAS
(2021)
Article
Physics, Applied
Lee R. Strobel, Benjamin C. Martell, Anatoli Morozov, Arthur Dogariu, Carmen Guerra-Garcia
Summary: This paper reports on electric field measurements of DC-driven positive streamer coronas in atmospheric-pressure air. The measurements show the self-pulsating behavior of the discharge, challenging the existing explanations and suggesting a propagating wave-like feature.
APPLIED PHYSICS LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Oscar Monerris-Belda, Raul Cervera Marin, Miguel Rodriguez Jodar, Elena Diaz-Caballero, Carlos Alcaide Guillen, John Petit, Vicente E. Boria, Benito Gimeno, David Raboso
Summary: The study presents a novel RF breakdown detection system, which offers several advantages over the microwave nulling system. This new system uses a larger analysis bandwidth, therefore reducing the cases in which small responses are difficult to be classified.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2021)
Article
Engineering, Electrical & Electronic
Jordi-Roger Riba
Summary: This paper investigates the electrical discharge phenomenon occurring in aircraft electrification and finds a relationship between electrical and optical phenomena involved in the discharge process. The paper shows that the density of charged particles generated during the discharge process is positively correlated with the intensity of corona images obtained with a digital imaging sensor sensitive to near UV and visible wavelength ranges.
SENSORS AND ACTUATORS A-PHYSICAL
(2023)
Review
Physics, Applied
Natalia Yu Babaeva, George Naidis
Summary: This paper presents a review of general and specific properties of ionization waves-streamers, discussing characteristics of streamers in gases and liquids, sprites in the Earth's atmosphere, and guided streamers in cold atmospheric-pressure plasma jets. Information on streamer structure, propagation velocity, and radius, as well as parameters of the streamer plasma obtained using diagnostic methods, numerical modeling, and analytical approach in various media are analyzed.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Physics, Fluids & Plasmas
N. Yu Babaeva, G. Naidis
Summary: The study focuses on CO2 molecule conversion through electron impact dissociation, estimating efficiency using various dissociation cross sections. The best fit with experimental data for corona and dielectric-barrier discharges is found using Phelps' cross section for excitation of electronic states with an energy threshold of 10.5 eV under specific electric field conditions.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2021)
Article
Physics, Applied
N. G. C. Ferreira, G. Naidis, M. S. Benilov
Summary: The deviations from the similarity law observed in experiments on discharge ignition and breakdown in corona-like configurations at high and very high pressures are attributed to enhanced ionization of air molecules near microprotrusions. The 2D numerical modeling study shows qualitative agreement with the experiment for protrusion heights of around 50 μm. The enhancement of field electron emission from the surface of the negative electrode due to electric field amplification on microprotrusions was found insignificant compared to enhanced ionization in the gas phase.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Physics, Fluids & Plasmas
Natalia Yu Babaeva, George Naidis
Summary: This paper investigates the effect of externally applied electric fields on the dynamics and parameters of an atmospheric pressure plasma jet using a 2D computational approach. It is found that positive voltage pulses increase the IW velocity, while negative voltage pulses decrease it, and the modulation of IW morphology depends on the ratio of ignition/external voltages.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
George Naidis
Summary: This study investigates the effect of microprotrusions at electrode surfaces on the discharge inception in hydrocarbon liquids in corona-like gap configurations. The inception field is estimated for cylindrical protrusions of various lengths and radii. The calculated inception fields agree well with experimental data for rods with radii of about a centimeter when the protrusions have lengths and radii of 20-50 μm and 1-2 μm, respectively. These protrusion parameters are similar to those obtained in previous analysis of discharge inception in compressed gases.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2022)
Article
Physics, Fluids & Plasmas
Dmitry Tereshonok, Natalia Yu Babaeva, Georgy Naidis, Artem G. Abramov, Aleksandr Ugryumov
Summary: Numerical simulation has been conducted to study the development of ionization waves in pure argon at atmospheric pressure. The velocities and plasma parameters of cathode- and anode-directed ionization waves are obtained, and the dynamics and structure of the streamers are analyzed. The effects of variation in the background density of charged species are considered, and the roles of different ionization mechanisms during streamer formation and propagation are revealed.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2022)
Article
Physics, Applied
G. Naidis, N. Yu Babaeva
Summary: An approach for evaluating plasma parameters and conversion factor in glow discharges in CO2-N-2 mixtures at low pressures is presented. Analytical expressions relating plasma characteristics in the mixtures with those in pure CO2 have been obtained. It is found that dissociation of CO2 molecules in collisions with electronically excited N-2 molecules significantly affects the conversion rate. The obtained dependence of plasma parameters and conversion factor on the nitrogen molar fraction agrees well with experimental data.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
G. Naidis, N. Yu Babaeva
Summary: A model of repetitively pulsed low-pressure CO2 discharges is developed, and plasma characteristics during the pulses and in the afterglow periods, as well as the CO2 conversion factor, are calculated. The computed results are in agreement with available experimental data.
PHYSICS OF PLASMAS
(2022)
Article
Physics, Applied
G. Naidis, N. Yu Babaeva
Summary: The excitation dynamics of the asymmetric vibrational mode of CO2 molecules in a nanosecond discharge is simulated and it is demonstrated that the density dynamics of these levels, calculated using generally accepted rate constants, agree reasonably well with experimental data.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
Natalia Yu Babaeva, George Naidis
Summary: In this paper, the effects of a helium plasma jet interacting with a dielectric plate at a floating potential are investigated using computational methods. It is found that for certain grazing angles, the plasma jet envelopes the plate and the ionization wave splits at the edge. This is attributed to the electric field direction and buoyancy forces. The production and delivery of charged and neutral species to the plate surfaces are also discussed, as well as the effect of buoyancy forces on reactive species distributions.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Applied
N. Yu Babaeva, G. Naidis, D. Tereshonok, V. F. Tarasenko, D. Beloplotov, D. A. Sorokin
Summary: This paper investigates the structure and dynamics of wide negative streamers in air and helium under high overvoltages with short rise times applied to a sharp needle electrode, using both experimental and computational methods. Different shapes of streamers were observed when fast electrons were taken into account. The velocities of streamers were significantly increased with the presence of fast electrons. Additionally, the study also observed the formation of a discharge with several parallel streamers under high overvoltages.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
G. V. Naidis, N. Yu. Babaeva
Summary: A 1D model of glow low-pressure CO2 discharges was developed and used to simulate stationary and repetitively pulsed discharges. The plasma characteristics obtained from the model were compared with experimental results and data from an approximate 0D approach. The agreement between the measured and calculated CO molar fraction was achieved by modifying the expression of the dissociation rate constant in the 1D model.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
N. Yu Babaeva, G. Naidis, V. F. Tarasenko, D. A. Sorokin, Cheng Zhang, Tao Shao
Summary: In this study, the properties of ionization waves (IWs) in a multi-pulsed plasma jet were investigated using a two-dimensional computational approach. The IWs were generated by applying three short negative pulses with a repetition frequency of 12.5 MHz. The simulations accounted for both surface charges and space charges accumulated inside and outside the tube. It was found that IWs could emerge from the tube exit at both the rising and falling edges of the pulses, and the remnants of charges played a crucial role in the discharge evolution. The IWs generated by the second pulse significantly increased the plasma plume length, while those generated by the third pulse eventually decayed due to the accumulated charges from previous pulses, which could lead to the extinction of IWs.
PLASMA SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Fluids & Plasmas
N. Yu Babaeva, G. Naidis, D. Tereshonok, T. Chernyshev, L. S. Volkov, M. M. Vasiliev, O. F. Petrov
Summary: In this study, we computationally investigated the process of CO2 splitting to carbon monoxide and oxygen in an atmospheric pressure microwave plasma torch. We used 2D and 1D models to demonstrate different stages of CO2 conversion. Contrary to our expectation, the gas temperature and plasma species behavior in the 1D model were found to be quite different from those obtained with the 2D code. We identified that the reverse gas flow near the central electrode was responsible for the observed discrepancies and achieved reasonable agreement between the two models by adjusting the flow rate in the 1D model.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Physics, Fluids & Plasmas
R. M. S. Almeida, P. G. C. Almeida, G. Naidis, M. S. Benilov
Summary: An eigenvalue problem for volume discharge ignition is formulated, considering photoionization and multiple ion species with various reactions. The Townsend ignition criterion is deduced and applied to different discharge ignition examples, showing accurate results with the neglect of diffusion and weak effect of photoionization.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
