The Asia–Pacific International Symposium on the Basics and Applications of Plasma Technology (APSPT) has been held in Taiwan or Japan every two to four years since 1997. It is an important annual event in the Asia–Pacific area and has been a great platform for scientists all around the world sharing novel and state-of-the-art research findings and exchanging innovative ideas in the field of plasma

Paint protects the outer surface of ships. The antifouling component of paint prevents aquatic organisms from attaching to the surface of the ship. However, marine paints deteriorate with time. Therefore, periodic repainting is required. Repainting is performed via sandblasting, in which an abrasive is sprayed onto the surface of the paint. However, in this method, the base material of the paint is

The ozone behavior on heated catalytic probe surfaces is examined in gas flow downstream of atmospheric-pressure dielectric barrier discharge ozonizers. Negative and positive variations in the probe voltage as a function of probe heating current enable one to discriminate catalytic dissociation of ozone at low temperatures and catalytic recombination of oxygen radicals at high temperatures, respectively

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Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers.

The potential impacts of extremely low temperature on threshold inception characteristics of negative corona discharge are straightly estimated through the numerical algorithm and the extremely low temperature experiments. First, the inception criterion models of glow and streamer corona are solved for assessing the salient characteristics of corona inception at varying temperatures. The feasibility

The use of stationary solvers instead of approximate solution methods or time-dependent solvers, which are standard tools in gas discharge modeling, allows one to develop a very fast and robust numerical model for studying the time-averaged characteristics of dc corona discharges. Such an approach is applied to dc corona discharges in point-plane gaps in ambient air. A wide range of currents of both

A simplified and obvious electrotechnique model of the electric field enhancement in front of the propagating gas-discharge plasma channel is presented. A theory, developed some time ago by Yakovlenko, is criticized proving that a displacement of the electric field due to the plasma polarization behind the flat channel front is sufficient for the field enhancement ahead of the front. Arguing with this

A rigorous theoretical investigation is made of arbitrary amplitude heavy nucleus-acoustic (NA) solitary waves (SWs) in a fully ionized multinucleus plasma system (consisting of thermally degenerate electron species (DES) and nondegenerate warm light as well as heavy nucleus species). The pseudo-potential approach, which is valid for the arbitrary amplitude SWs, is employed. The subsonic and supersonic

The high velocity of the re-entry object causes its surface to be enveloped with a plasma sheath. In the process of target detection of re-entry objects, the plasma sheath with fluid characteristics results in multiple reflected signals in the radar echo. Multiple targets appear in the 1-D range profile following pulse compression processing of a multicomponent echo signal. We refer to targets different

The characteristics of plasmons in nonuniform plasma are studied. It is found that plasmons can be supported by the interface between two plasma having different plasma frequencies, while their frequencies depend on the ratio of the lower plasma frequency to the higher plasma frequency. Interestingly, when the ratio is about 1, the frequencies of plasmons are equal to these plasma frequencies approximately

A novel high-performance wideband balanced bandpass filter based on transversal signal-interference techniques is proposed in this article. Two signal-propagation paths consisted of coupled lines structure are used to realize two transmission zeros for the differential mode passband. Folding coupled lines are used to reduce the size of the balanced filter, and the source–load cross-coupling lines can

In this article, RF behavior studies on a $W$ -band continuous wave (CW) gyrotron for industrial, scientific, and medical applications are presented. Two different designs are carried out for the output power level of 50 and 100 kW. The mode competition with the first and second harmonic neighboring modes is carefully investigated, and TE 6,2 and TE 10,4 are chosen as the operating modes for these

This article presents a dual-band bandpass filter based on the double-sided spoof surface plasmon polaritons-line. The whole structure consists of a dual-band filtering part and two SSPPs lowpass filtering parts. Simulated results show that the proposed dual-band bandpass filter has an excellent dual-band filtering performance and wide upper band suppressions. Simulated bandwidths of two passbands

A particle-in-cell simulation of a powerful reflex triode with a radially converging magnetized electron beam was carried out. The complex dynamics of the electron beam and the generation characteristics of the reflex triode were studied. It is shown that a virtual cathode and, for the first time, a disk-shaped squeezed state of the beam were formed in it. Radial profiles of the electron temperature

The miniaturized traveling wave tube (TWT) is a kind of high-efficiency, high-power, long-lifetime power amplifier which is an attractive choice for many applications, such as outer space exploration, phased array radar detection, unmanned aerial vehicle (UAV) communication, and on-chip application. In this article, a sheet beam miniaturized TWT with V-shaped meander-line slow wave structure (SWS)

In this article, a simple periodic 1-D magnetized plasma photonic crystal (PPC) is proposed. The effects of plasma frequency and plasma cyclotron frequency on the absorption of such magnetized PPCs are investigated theoretically by the transfer matrix method. The simulated results show that, for the TM wave, a tunable absorption window in the transmission region (AWTR) can be achieved when the incident

In this article, an analysis of the propagation constant and the characteristic impedance of a ridge gap waveguide (RGW) is proposed, which includes the comparison of the phase variation between three kinds of guiding structures, the approximation for the propagation constant of RGW, and the variation of characteristic impedances and phase characteristics. According to the analysis, the RGW technology

We present a new approach to the study of the stability of vacuum electronic devices (VEDs) using the Naval Research Laboratory (NRL) large-signal code TESLA-Z. The approach combines a precomputed complex impedance matrix, $\hat {Z}$ , describing the structure with a TESLA-Z computed admittance matrix, $\hat {Y}_{ \boldsymbol {bt}}$ , characterizing the electron beam and beam tunnel. The gain matrix

The exhaust ion stream from an electron cyclotron resonance (ECR) plasma source is investigated in detail. Two sets of coils allow for different shapes of the external field under which the plasma is created. Parameters in the form of electron density $n_{e}$ , electron temperature $T_{e}$ , and ion energy distribution function (IEDF) are evaluated using Langmuir probes and retarding field energy analyzers

The energy and density of laser-generated Si and Ge plasma ions have been investigated by using Faraday cup (FC). Nd: YAG laser (532 nm, 6 ns) at different irradiances ranging from 4 to 7.1 GWcm −2 has been employed as an irradiation source. FC measurements reveal two time-of-flight (TOF) ion signal peaks. From the observed TOF signals of ions, the kinetic energy and density of laser induced Si and

Atmospheric pressure plasma jets driven by ac and pulsed-dc voltage were characterized, operating in helium with different admixture fractions up to 2% pure air, N 2 , and O 2 . The absolute production efficiency of nitrogen dioxide, nitric oxide, ozone, hydroxyl, and atomic oxygen was measured when plasma was processing real biological tissue. The power consumption of each power source, the effect

Recently, transformers with toroidal core have received much attention. The compactness and weight of these kinds of transformers make them suitable for power electronics applications. In some areas, it is necessary to have a toroidal transformer with particular parasitic elements such as leakage inductance. So, there is a need for a precise method to calculate the exact amount of leakage inductance

Electrical impedance spectroscopy (EIS) is a powerful method that can be used to facilitate the treatment process by providing on-line and reliable information about the impedance properties of the sample under the treatment. In most of the research studies, EIS methods were applied to detect and monitor the growth of micro-organisms in solutions. However, this technique has been rarely applied to

Compulsator provides an excellent approach to achieve compact energy storage and pulsed power generation for several multi-MJ, multi-GW applications, including electromagnetic launchers, directed energy systems, and fusion reactors. There is a continuous research effort toward increasing the power capability and compactness of this machine since its invention. In general, specific machine designs aim

Research on the effect of pulsed electric field in cell electroporation attracts more attention, especially tumor ablation. This puts forward higher requirements for pulsed electric field parameters. The shape of the pulse waveform was also required in different electroporation applications. Based on this, a multilevel pulse generator with series capacitor structure was proposed in this article. Besides

This article presents an experimental arrangement which, using 3-D numerical modeling, aims to study biomedical effects using subnanosecond pulsed electric fields (PEFs). As part of a major effort into developing contactless technology, the final aim of this study is to determine conditions of the applied PEFs (number of pulses, strength, pulse repetition frequency) able to produce electropermeabilization

Due to their fast switching capabilities, silicon carbide (SiC) MOSFETs are increasingly used in high-voltage pulsed-power circuits where fast and flexible high-voltage pulses are required (e.g. for plasma-processing applications), such as in our solid-state Impedance-matched Marx generator. The turn-on time of SiC MOSFETs mainly depends on the gate-driving technique and its implementation. Therefore

High-voltage (HV) pulsed power generators are very important in plasma generation in corona discharge reactors. With the advent of new fast switches technologies such as silicon carbide (SiC) and gallium nitride (GaN), electromagnetic interference (EMI) noise in such systems are very challenging. In this article, electromagnetic compatibility (EMC) modeling and conducted EMI analysis for a pulse generator

Being widely used in the design of the future Z-pinch accelerators, the monolithic radial transmission line (MRTL) is considered to have high-pass characteristic. However, it was found with 3-D electromagnetic simulation that the MRTL has resonant frequencies in high-frequency region. At the resonant frequencies, the electromagnetic wave cannot be delivered to the load. The space-time distributions

Magnetic implosion of liners is usually accompanied by the development of the Rayleigh–Taylor instability, which makes it hard to achieve high energy densities. However, the liners, which are thin compared with their skin layer (let us call them resistive), can also experience a different kind of instability, when parallel currents in different liner parts are attracted and draw these parts together

In this article, the sheath growth of the vacuum circuit breaker and its initial conditions of the calculation are introduced. The images of cathode spots distribution and waveforms of postarc current under different frequencies are obtained by medium- to high-frequency current breaking experiments. The quantitative relationship of $D$ and $di/dt$ with the variation of current frequency $f$ and current

The effective temperatures of the positive and negative charge carriers in impact plasma are measured experimentally. The measurements are performed using a dust accelerator using polypyrrole (PPy)-coated olivine dust particles impacting onto a tungsten (W) target in four velocity bins: 2–3.6, 5–6.6, 8–12, and 12–18 km/s. The setup measures the retained impact charge as a function of applied bias potential

Plasma–surface interactions caused by electric propulsion devices are an important spacecraft aspect of the design that is difficult to measure in ground-based facilities. The negatively biased solar panel surfaces attract the slow-moving charge exchange (CEX) ions generated inside an ion core plume, which can cause surface sputtering on the protective coatings of the solar panels. We use a fully kinetic

A concept of SUb-atmospheric Radio-frequency Engine (SURE) designed for the near-space environment is proposed. The antenna wrapping quartz tube consists of two solenoid coils with variable separation distance and is driven by radio frequency power supply (13.56 MHz–1 kW). The discharge involves inductive coupling under each solenoid coil and capacitive coupling between them. This novel scheme can

A motor-driven, high-current switch is being designed by Stäubli Electrical Connectors in collaboration with Princeton Plasma Physics Laboratory to reverse the DIII-D Toroidal field coil current. The existing field reversing procedure requires approximately 4 h of labor performed between run days to reconfigure the bus work, thus requiring a separate run day to complete experimental scans with both

The vertical stability coil will be used in China Fusion Engineering Test Reactor (CFETR) to improve its control capability on plasma. In view of the severe operation environment and high reliable requirement, it is a challenge for the coil to keep reliability during the whole lifetime, considering the prominent advantages of induction brazing, which is proposed for the coil joint connection. According

To explore the influence of different caliber on the electromagnetic field and temperature field of railguns, an electromagnetic-thermal coupling analysis is carried out on three kinds of caliber railguns by Maxwell 3-D and ANSYS Workbench. The current density and temperature distribution on the contact surface between armature and rails of three kinds of caliber railguns are obtained, respectively

A coaxial $V$ -band coaxial transit-time oscillator (TTO) operating in TM 02 mode with a low guiding magnetic field is presented and investigated. The interaction region is designed to operate in TM 02 mode to increase power handling capacity. The number of gaps of interaction cavities is increased and the beam tunnel is widened to achieve mode excitation and low guiding magnetic field operation. A

An ultrashort pulse high electric field provides new biological applications, such as sterilization of a packaged food. In this study, we investigate the effect on yeast cells by a high-frequency and high-intensity burst pulse for the purpose of killing cells in packaged food. Previously, we showed that applying a burst pulse to cells was more effective in causing cell death than repeatedly supplying

Research in ITER grade magnetic confinement fusion uses high power radio frequency sources and accelerated neutral particles to heat the plasma to fusion temperature. These devices require high voltage DC power supplies in the range of several tens of kilovolts at a power level of few megawatts. Pulse step modulation technique is widely used to generate high voltage by cascading bulk numbers of low

Rogowski coils for fast pulse current measurement need sparse winding. However, sparse winding might make the coil distribution uneven and result in measurement error as the measured conductor is placed eccentrically or obliquely or if there is nearby current external to the coil. In this article, the induced electromotive force and the resulting measurement error are determined for nonuniform turn

Treatment of gas and water for environmental applications requires a high-voltage, fast-rising pulse to act on the plasma gas or water treating reactor, but the existing stacked high-voltage pulse generator is arduous to use owing to its large size, high cost, and relatively slow pulse rise time. In this study, we propose a low-cost, small-volume pulsed power modulator that can significantly reduce

Presents the table of contents for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

The winner of the 2020 TPS Best Paper Award has been selected (please refer to our TPS home page for details about the award at https://ieee-npss.org/publications/transactions-on-plasma-science/ ). This year is the second year that the award is being given, and I am pleased to announce that Prof. Chandrashekhar Joshi, Department of Electrical and Computer Engineering, University of California at Los

A new method based on the charge simulation technique is proposed for computing the electric field in a short uniform field gap with space charge and without space charge of avalanches growing in the gap. The self-space-charge field of the avalanche is evaluated to result in field enhancement ahead of the avalanche due to electrons at its head and behind the avalanche due to positive ions in its wake

The phenomenon of shock wave refraction on a gaseous interface with plasma was analyzed for nonideal gas effects. The developed model was applied to nondissociating diatomic nitrogen gas at 3000 K. Comparatively to ideal gas, the interface reflectivity was found noticeably decreased resulting in 12% more intense shock transmission. The transition point determining the character of reflected wave was

This article presents a comparative investigation on behaviors of electrons in the Ar and He plasma jets by means of the numerical simulation based on a typical needle-plate discharge configuration with positive applied pulsed voltage and a 1-D particle-in-cell Monte-Carlo collision (PIC-MCC) method. Emphasis is placed on the electrons in the bullet in the jets. In Ar, the bullet velocity is low and

The theory of electrostatic (or, more accurately, slow electric or quasi-electrostatic) waves propagation in 1-D magnetized plasma periodic structures, at frequencies below both the plasma and cyclotron frequencies, is presented using the transfer matrix method. It assumes that the applied static magnetic field is perpendicular to the surface of the plasma layers. The dispersion relation of the waves

The converter transformer is the most important piece of equipment in ultrahigh voltage direct current (UHVDC) transmission systems. The rectifying valve side of the converter transformer is dealing with composite voltages, containing both ac and dc components. Therefore, the characteristics of the partial discharge (PD) in oil–paper insulation of such rectifying valves are different from those of

A theoretical investigation is carried out for understanding the properties of three-dimensional degenerate pressure-driven (DPD) gravitoelectrostatic solitary waves (SWs) in a general (but realistic) self-gravitating degenerate quantum plasma (SGDQP) medium whose constituents are noninertial degenerate electron and inertial degenerate heavy and light ions/nuclei/elements. The formation of solitary

Plasma immersion ion implantation (PIII) was conducted in a large volume chamber with a current-controlled high-voltage pulser, to test the vacuum, plasma, and PIII conditions, in a preparation for the treatments of large workpieces or the batch-processing mode. For that purpose, a rugged high-power pulser (10 kW average) based on solid-state moderate voltage pulse system (1 kV) was coupled to a high-voltage

The key subsystems of a high efficiency material processing gyrotron are designed at an operating frequency of 27.885 GHz. A triode-type electron gun is designed to launch hollow spiraling electron beam. The outer diameter of the gun is kept at 50 mm to lower inside diameter of the magnet. Start oscillation current for TE 02 operating as well as competing modes is plotted. The output power and efficiency

The drift orbital resonance theory has the potential to analyze and estimate the electron dynamics in a magnetron. Hence it has been utilized to examine the behavior of the rotating electron cloud in a spatial harmonic magnetron (SHM). Alteration of the theory variables, namely the orbital velocities, coefficients of radial expansion, gyrating circle radius, accelerating factor, etc., affects the electron

In this article, the power capabilities of the axially extracted virtual cathode oscillator are determined by analytical means. The used methodology comprises two stages. First, power limits are established by mathematical optimization of a Vircator power model calculating the average power radiated at a given frequency. Second, the analytical results are validated by comparison against computational

In this article, we discuss the use of a third harmonic component to the drive voltage on the grid of an inductive output tube (IOT). High-efficiency IOTs are typically characterized by efficiencies up to 70%–75%. However, the achievement of efficiencies greater than 80% would substantially reduce the operating costs of next-generation accelerators. In order to achieve this goal, we consider the addition

Plasma was generated in the focal region of a multikilowatt, 4.7-GHz continuous-wave (CW) microwave beam far removed from the walls of the vacuum chamber, minimizing the nonideal effects associated with plasma–wall and beam–wall interactions. Experiments were conducted with gas mixtures of argon, nitrogen, and oxygen at gas pressures ranging from 100 to 200 mtorr. Three types of discharges were observed

Turbulence in the plasma sheath around reentry vehicles is known to contribute to radio-communications blackout, but a practical laboratory model of that extreme environment remains elusive. Herein, we present a table-top plasma system with sustained, chaotic convection for that purpose. Strong sound waves exert acoustic radiation pressure on gradients within the plasma and are shown to drive sufficient

The gyromagnetic nonlinear transmission line (GNLTL) is a compact and solid-state high-power microwave source, which can be treated as a special coaxial transmission line partially filled with the ferrite material. Due to the complex interaction process of the electromagnetic fields with the dynamic damped precessional motion of the magnetization vector in the ferrite, it is of great challenge to theoretically