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“Low-pressure inductively coupled plasmas in hydrogen : impact of gas heating on the spatial distribution of atomic hydrogen and vibrationally excited states”. Smith GJ, Diomede P, Gibson AR, Doyle SJ, Guerra V, Kushner MJ, Gans T, Dedrick JP, Plasma sources science and technology 33, 025002 (2024). http://doi.org/10.1088/1361-6595/AD1ECE
Abstract: Non-equilibrium inductively coupled plasmas (ICPs) operating in hydrogen are of significant interest for applications including large-area materials processing. Increasing control of spatial gas heating, which drives the formation of neutral species density gradients and the rate of gas-temperature-dependent reactions, is critical. In this study, we use 2D fluid-kinetic simulations with the Hybrid Plasma Equipment Model to investigate the spatially resolved production of atomic hydrogen in a low-pressure planar ICP operating in pure hydrogen (10-20 Pa or 0.075-0.15 Torr, 300 W). The reaction set incorporates self-consistent calculation of the spatially resolved gas temperature and 14 vibrationally excited states. We find that the formation of neutral-gas density gradients, which result from spatially non-uniform electrical power deposition at constant pressure, can drive significant variations in the vibrational distribution function and density of atomic hydrogen when gas heating is spatially resolved. This highlights the significance of spatial gas heating on the production of reactive species in relatively high-power-density plasma processing sources.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.8
DOI: 10.1088/1361-6595/AD1ECE
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“Ionization and neutral gas heating efficiency in radio frequency electrothermal microthrusters : the role of driving frequency”. Leigh S, Doyle SJ, Smith GJ, Gibson AR, Boswell RW, Charles C, Dedrick JP, Physics of plasmas 31, 023509 (2024). http://doi.org/10.1063/5.0172646
Abstract: The development of compact, low power, charge-neutral propulsion sources is of significant recent interest due to the rising application of micro-scale satellite platforms. Among such sources, radio frequency (rf) electrothermal microthrusters present an attractive option due to their scalability, reliability, and tunable control of power coupling to the propellant. For micropropulsion applications, where available power is limited, it is of particular importance to understand how electrical power can be transferred to the propellant efficiently, a process that is underpinned by the plasma sheath dynamics. In this work, two-dimensional fluid/Monte Carlo simulations are employed to investigate the effects of applied voltage frequency on the electron, ion, and neutral heating in an rf capacitively coupled plasma microthruster operating in argon. Variations in the electron and argon ion densities and power deposition, and their consequent effect on neutral-gas heating, are investigated with relation to the phase-averaged and phase-resolved sheath dynamics for rf voltage frequencies of 6-108 MHz at 450 V. Driving voltage frequencies above 40.68 MHz exhibit enhanced volumetric ionization from bulk electrons at the expense of the ion heating efficiency. Lower driving voltage frequencies below 13.56 MHz exhibit more efficient ionization due to secondary electrons and an increasing fraction of rf power deposition into ions. Thermal efficiencies are improved by a factor of 2.5 at 6 MHz as compared to the more traditional 13.56 MHz, indicating a favorable operating regime for low power satellite applications.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.2
DOI: 10.1063/5.0172646
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“Unveiling the interaction mechanisms of cold atmospheric plasma and amino acids by machine learning”. Chai Z-N, Wang X-C, Yusupov M, Zhang Y-T, Plasma processes and polymers , 1 (2024). http://doi.org/10.1002/PPAP.202300230
Abstract: Plasma medicine has attracted tremendous interest in a variety of medical conditions, ranging from wound healing to antimicrobial applications, even in cancer treatment, through the interactions of cold atmospheric plasma (CAP) and various biological tissues directly or indirectly. The underlying mechanisms of CAP treatment are still poorly understood although the oxidative effects of CAP with amino acids, peptides, and proteins have been explored experimentally. In this study, machine learning (ML) technology is introduced to efficiently unveil the interaction mechanisms of amino acids and reactive oxygen species (ROS) in seconds based on the data obtained from the reactive molecular dynamics (MD) simulations, which are performed to probe the interaction of five types of amino acids with various ROS on the timescale of hundreds of picoseconds but with the huge computational load of several days. The oxidative reactions typically start with H-abstraction, and the details of the breaking and formation of chemical bonds are revealed; the modification types, such as nitrosylation, hydroxylation, and carbonylation, can be observed. The dose effects of ROS are also investigated by varying the number of ROS in the simulation box, indicating agreement with the experimental observation. To overcome the limits of timescales and the size of molecular systems in reactive MD simulations, a deep neural network (DNN) with five hidden layers is constructed according to the reaction data and employed to predict the type of oxidative modification and the probability of occurrence only in seconds as the dose of ROS varies. The well-trained DNN can effectively and accurately predict the oxidative processes and productions, which greatly improves the computational efficiency by almost ten orders of magnitude compared with the reactive MD simulation. This study shows the great potential of ML technology to efficiently unveil the underpinning mechanisms in plasma medicine based on the data from reactive MD simulations or experimental measurements. In this study, since reactive molecular dynamics simulation can currently only describe interactions between a few hundred atoms in a few hundred picoseconds, deep neural networks (DNN) are introduced to enhance the simulation results by predicting more data efficiently. image
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.5
DOI: 10.1002/PPAP.202300230
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“Investigation of O atom kinetics in O2plasma and its afterglow”. Albrechts M, Tsonev I, Bogaerts A, Plasma Sources Science and Technology 33, 045017 (2024). http://doi.org/10.1088/1361-6595/ad3f4a
Abstract: We have developed a comprehensive kinetic model to study the O atom kinetics in an O<sub>2</sub>plasma and its afterglow. By adopting a pseudo-1D plug-flow formalism within the kinetic model, our aim is to assess how far the O atoms travel in the plasma afterglow, evaluating its potential as a source of O atoms for post-plasma gas conversion applications. Since we could not find experimental data for pure O<sub>2</sub>plasma at atmospheric pressure, we first validated our model at low pressure (1–10 Torr) where very good experimental data are available. Good agreement between our model and experiments was achieved for the reduced electric field, gas temperature and the densities of the dominant neutral species, i.e. O<sub>2</sub>(a), O<sub>2</sub>(b) and O. Subsequently, we confirmed that the chemistry set is consistent with thermodynamic equilibrium calculations at atmospheric pressure. Finally, we investigated the O atom densities in the O<sub>2</sub>plasma and its afterglow, for which we considered a microwave O<sub>2</sub>plasma torch, operating at a pressure between 0.1 and 1 atm, for a flow rate of 20 slm and an specific energy input of 1656 kJ mol<sup>−1</sup>. Our results show that for both pressure conditions, a high dissociation degree of ca. 92% is reached within the discharge. However, the O atoms travel much further in the plasma afterglow for<italic>p</italic>= 0.1 atm (9.7 cm) than for<italic>p</italic>= 1 atm (1.4 cm), attributed to the longer lifetime (3.8 ms at 0.1 atm vs 1.8 ms at 1 atm) resulting from slower three-body recombination kinetics, as well as a higher volumetric flow rate.
Keywords: A1 Journal Article; oxygen plasma, pseudo-1D plug-flow kinetic model, O atoms, low-pressure validation, atmospheric pressure microwave torch; Plasma, laser ablation and surface modeling Antwerp (PLASMANT) ;
Impact Factor: 3.8
DOI: 10.1088/1361-6595/ad3f4a
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“Comprehensive modelling network for dc glow discharges in argon”. Bogaerts A, Plasma sources science and technology 8, 210 (1999). http://doi.org/10.1088/0963-0252/8/2/003
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 27
DOI: 10.1088/0963-0252/8/2/003
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“Semianalytical description of nonlocal secondary electrons in a radio-frequency capacitively coupled plasma at intermediate pressures”. Berezhnoi S, Kaganovich I, Misina M, Bogaerts A, Gijbels R, IEEE transactions plasma science 27, 1339 (1999). http://doi.org/10.1109/27.799810
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.052
Times cited: 7
DOI: 10.1109/27.799810
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“Monte Carlo model for the argon ions and fast argon atoms in a radio-frequency discharge”. Bogaerts A, Gijbels R, IEEE transactions on plasma science 27, 1406 (1999). http://doi.org/10.1109/27.799819
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.052
Times cited: 15
DOI: 10.1109/27.799819
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“Electron energy distribution function in capacitively coupled RF discharges: differences between electropositive Ar and electronegative SiH4 discharges”. Yan M, Bogaerts A, Goedheer WJ, Gijbels R, Plasma sources science and technology 9, 583 (2000). http://doi.org/10.1088/0963-0252/9/4/314
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 21
DOI: 10.1088/0963-0252/9/4/314
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“Kinetic modeling of relaxation phenomena after photodetachment in a rf electronegative SiH4 discharge”. Yan M, Bogaerts A, Gijbels R, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 63 (2001). http://doi.org/10.1103/PhysRevE.63.026405
Abstract: The global relaxation process after pulsed laser induced photodetachment in a rf electronegative SIH4 discharge is studied by a self-consistent kinetic one-dimensional particle-in-cell-Monte Carlo model. Our results reveal a comprehensive physical picture of the relaxation process, including the main plasma variables, after a perturbation up to the full recovery of the steady state. A strong influence of the photodetachment on the discharge is found, which results from an increase of the electron density, leading to a weaker bulk field, and hence to a drop in the high energy tail of the electron energy distribution function (EEDF), a reduction of the reaction rates of electron impact attachment and ionization, and a subsequent decrease of the positive and negative ion densities. All the plasma quantities related to electrons recover synchronously. The recovery time of the ion densities is about 1-2 orders of magnitude longer than that of the electrons due to different recovery mechanisms. The modeled behavior of all the charged particles agrees very well with experimental results from the literature. In addition, our work clarifies some unclear processes assumed in the literature, such as the relaxation of the EEDF, the evolution of the electric field, and the recovery of negative ions.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 4
DOI: 10.1103/PhysRevE.63.026405
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“The ion- and atom-induced secondary electron emission yield: numerical study for the effect of clean and dirty cathode surfaces”. Bogaerts A, Gijbels R, Plasma sources science and technology 11, 27 (2002). http://doi.org/10.1088/0963-0252/11/1/303
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 51
DOI: 10.1088/0963-0252/11/1/303
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“Evolution of charged particle densities after laser-induced photodetachment in a strongly electronegative RF discharge”. Yan M, Bogaerts A, Gijbels R, IEEE transactions on plasma science 30, 132 (2002). http://doi.org/10.1109/TPS.2002.1003959
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.052
DOI: 10.1109/TPS.2002.1003959
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“A one-dimensional fluid model for an acetylene rf discharge: a study of the plasma chemistry”. Herrebout D, Bogaerts A, Gijbels R, Goedheer WJ, Vanhulsel A, IEEE transactions on plasma science 31, 659 (2003). http://doi.org/10.1109/TPS.2003.815249
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.052
Times cited: 26
DOI: 10.1109/TPS.2003.815249
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“Numerical investigation of ion energy distribution functions in single and dual frequency capacitively coupled plasma reactors”. Georgieva V, Bogaerts A, Gijbels R, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 69, 026406 (2004). http://doi.org/10.1103/PhysRevE.69.026406
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 97
DOI: 10.1103/PhysRevE.69.026406
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“Numerical investigation of particle formation mechanisms in silane discharges”. de Bleecker K, Bogaerts A, Gijbels R, Goedheer W, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 69, 056409 (2004). http://doi.org/10.1103/PhysRevE.69.056409
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 74
DOI: 10.1103/PhysRevE.69.056409
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“Investigation of growth mechanisms of clusters in a silane discharge with the use of a fluid model”. de Bleecker K, Bogaerts A, Goedheer W, Gijbels R, IEEE transactions on plasma science 32, 691 (2004). http://doi.org/10.1109/TPS.2004.826095
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.052
Times cited: 29
DOI: 10.1109/TPS.2004.826095
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“Numerical models of the planar magnetron glow discharges”. Kolev I, Bogaerts A, Contributions to plasma physics 44, 582 (2004). http://doi.org/10.1002/ctpp.200410085
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 1.44
Times cited: 22
DOI: 10.1002/ctpp.200410085
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“Modeling of the formation and transport of nanoparticles in silane plasmas”. de Bleecker K, Bogaerts A, Goedheer W, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 70, 056407 (2004). http://doi.org/10.1103/PhysRevE.70.056407
Abstract: The behavior of nanoparticles in a low-pressure silane discharge is studied with the use of a self-consistent one-dimensional fluid model. Nanoparticles of a given (prescribed) radius are formed in the discharge by the incorporation of a dust growth mechanism, i.e., by including a step in which large anions (typically Si12H−25), produced in successive chemical reactions of anions with silane molecules, are transformed into particles. Typically a few thousand anions are used for one nanoparticle. The resulting particle density and the charge on the particles are calculated with an iterative method. While the spatial distribution and the charge of the particles are influenced by the plasma, the presence of the nanoparticles will in turn influence the plasma properties. Several simulations with different particle radii are performed. The resulting density profile of the dust will greatly depend on the particle size, as it reacts to the shift of the balance of the different forces acting on the particles.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 31
DOI: 10.1103/PhysRevE.70.056407
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“Terahertz radiation from oscillating electrons in laser-induced wake fields”. Cao L-H, Yu W, Xu H, Zheng C-Y, Liu Z-J, Li B, Bogaerts A, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 70, 046408 (2004). http://doi.org/10.1103/PhysRevE.70.046408
Abstract: Strong terahertz (1THz=1012Hz) radiation can be generated by the electron oscillation in fs-laser-induced wake fields. The interaction of a fs-laser pulse with a low-density plasma layer is studied in detail using numerical simulations. The spatial distribution and temporal evolution of terahertz electron current developed in a low-density plasma layer are presented, which enables us to calculate the intensity distribution of THz radiation. It is shown that laser and plasma parameters, such as laser intensity, pulse width, and background plasma density, are of key importance to the process. The optimum condition for wake-field excitation and terahertz emission is discussed upon the simulation results. Radiation peaked at 6.4 THz, with 900 fs duration and 9% bandwidth, can be generated in a plasma of density 5×1017cm−3. It turns out that the maximum radiation intensity scales as n03a04 when wake field is resonantly excited, where n0 and a0 are, respectively, the plasma density and the normalized field amplitude of the laser pulse.
Keywords: A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 9
DOI: 10.1103/PhysRevE.70.046408
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“Hollow cathode discharges with gas flow: numerical modelling for the effect on the sputtered atoms and the deposition flux”. Bogaerts A, Okhrimovskyy A, Baguer N, Gijbels R, Plasma sources science and technology 14, 191 (2005). http://doi.org/10.1088/0963-0252/14/1/021
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 9
DOI: 10.1088/0963-0252/14/1/021
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“Role of the thermophoretic force on the transport of nanoparticles in dusty silane plasmas”. de Bleecker K, Bogaerts A, Goedheer W, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 71, 066405 (2005). http://doi.org/10.1103/PhysRevE.71.066405
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 25
DOI: 10.1103/PhysRevE.71.066405
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“Influence of electron recapture by the cathode upon the discharge characteristics in dc planar magnetrons”. Kolev I, Bogaerts A, Gijbels R, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 72, 056402 (2005). http://doi.org/10.1103/PhysRevE.72.056402
Abstract: In dc magnetrons the electrons emitted from the cathode may return there due to the applied magnetic field. When that happens, they can be recaptured or reflected back into the discharge, depending on the value of the reflection coefficient (RC). A 2d3v (two-dimensional in coordinate and three-dimensional in velocity space) particle-in-cellMonte Carlo model, including an external circuit, is developed to determine the role of the electron recapture in the discharge processes. The detailed discharge structure as a function of RC for two pressures (4 and 25mtorr) is studied. The importance of electron recapture is clearly manifested, especially at low pressures. The results indicate that the discharge characteristics are dramatically changed with varying RC between 0 and 1. Thus, the electron recapture at the cathode appears to be a significant mechanism in magnetron discharges and RC a very important parameter in their correct quantitative description that should be dealt with cautiously.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 29
DOI: 10.1103/PhysRevE.72.056402
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“Perturbation of collisional plasma flow around a charged dust particle: kinetic analysis”. Schweigert IV, Schweigert VA, Peeters FM, Physics of plasmas 12, 113501 (2005). http://doi.org/10.1063/1.2076527
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.115
Times cited: 15
DOI: 10.1063/1.2076527
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“Computer simulations for processing plasmas”. Bogaerts A, de Bleecker K, Georgieva V, Kolev I, Madani M, Neyts E, Plasma processes and polymers 3, 110 (2006). http://doi.org/10.1002/ppap.200500065
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.846
Times cited: 8
DOI: 10.1002/ppap.200500065
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“PIC –, MCC numerical simulation of a DC planar magnetron”. Kolev I, Bogaerts A, Plasma processes and polymers 3, 127 (2006). http://doi.org/10.1002/ppap.200500118
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.846
Times cited: 27
DOI: 10.1002/ppap.200500118
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“Detailed modeling of hydrocarbon nanoparticle nucleation in acetylene discharges”. de Bleecker K, Bogaerts A, Goedheer W, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 73, 026405 (2006). http://doi.org/10.1103/PhysRevE.73.026405
Abstract: The initial stage of nanoparticle formation and growth in radiofrequency acetylene (C2H2) plasmas is investigated by means of a self-consistent one-dimensional fluid model. A detailed chemical kinetic scheme, containing electron impact, ion-neutral, and neutral-neutral reactions, has been developed in order to predict the underlying dust growth mechanisms and the most important dust precursors. The model considers 41 different species (neutrals, radicals, ions, and electrons) describing hydrocarbons (CnHm) containing up to 12 carbon atoms. Possible routes for particle growth are discussed. Both positive and negative ion reaction pathways are considered, as consecutive anion- and cation-molecule reactions seem to lead to a fast build up of the carbon skeleton.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 89
DOI: 10.1103/PhysRevE.73.026405
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“Spectrum of classical two-dimensional Coulomb clusters”. Nelissen K, Matulis A, Partoens B, Kong M, Peeters FM, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 73, 016607 (2006). http://doi.org/10.1103/PhysRevE.73.016607
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.366
Times cited: 33
DOI: 10.1103/PhysRevE.73.016607
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“Plasma characteristics of an Ar/CF4/N2 discharge in an asymmetric dual frequency reactor: numerical investigation by a PIC/MC model”. Georgieva V, Bogaerts A, Plasma sources science and technology 15, 368 (2006). http://doi.org/10.1088/0963-0252/15/3/010
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 35
DOI: 10.1088/0963-0252/15/3/010
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“Negative ion behavior in single- and dual-frequency plasma etching reactors: particle-in-cell/Monte Carlo collision study”. Georgieva V, Bogaerts A, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 73, 036402 (2006). http://doi.org/10.1103/PhysRevE.73.036402
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 7
DOI: 10.1103/PhysRevE.73.036402
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“Simulation of disk- and band-like voids in dusty plasma systems”. Liu YH, Chen ZY, Huang F, Yu MY, Wang L, Bogaerts A, Physics of plasmas 13, 052110 (2006). http://doi.org/10.1063/1.2201058
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.115
Times cited: 20
DOI: 10.1063/1.2201058
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“Structure of multispecies charged particles in a quadratic trap”. Liu YH, Chen ZY, Yu MY, Wang L, Bogaerts A, Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics 73, 047402 (2006). http://doi.org/10.1103/PhysRevE.73.047402
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.366
Times cited: 25
DOI: 10.1103/PhysRevE.73.047402
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