Plasma Research Express

Abstract The mechanism of generation of terahertz (THz) radiation with beating of two supergausssian lasers in corrugated density plasma containing hot electron-positron (e-p) is revisited. Resonance condition for optical excitation of THz emission is reported to be modified due to finite temperature of plasma species (electrons-positrons to the few order keV range) in the presence of weak collisions. The collision frequency is optimized to the range ν ≤ 0.5 ω p in the e-p plasma depending on the temperature and collisional rates. The effect of electron temperature, collision frequency and suitability of supergaussian laser is investigated on phase modulation to achieve highest emitted THz field with 6% efficiency of the mechanism.

S Divya

Impact of hot electrons on optical excitation of terahertz radiation by beating of supergaussian lasers in electron-positron collisional plasma

电子-正电子碰撞等离子体中超高斯激光拍频对太赫兹辐射光激发的电子热效应

Abstract According to simulation results from FDTD, Fano resonance of the air-Si-Si-air combined waveguide cavity was mainly studied, including the distribution of the magnetic field, quality factor, extinction coefficient and transmission efficiency. Fano resonance was related to the height of Si. When the height H 2 = 140 nm of Si and the height of H 1 = 300 nm, there was higher extinction coefficient in the resonant cavity and the better quality of the resonator, whose transmission efficiency of surface plasma was up to 89% for 1110 nm. This combined cavity had very good filtering effect.

Shu Li

Shuguang Chen

Shifang Xiao

Xiang Zhai

Huangqing Liu

Jingjing Mao

Jianzhong Mao

Fano resonance of air-Si waveguide cavity

空气-硅波导腔的Fano共振

Abstract This work addresses the negative ionization of hydrogen particles on low work function metal surfaces, which is an important process for the field of the surface plasma negative ion beams sources. We present the theoretical model for the computer calculation of the negative ionization probability which takes into account the component of atom/ion velocity, parallel to the surface. The calculated negative ionization probability of hydrogen quantitatively fits to the experimental data in the wide range of ion exit energies. The theoretical estimation shows, that for the low work function converter surfaces ( φ ∼ 1.5 eV) the negative ionization probability of hydrogen can be enhanced up to 30% if the hydrogen has velocity component parallel to the surface ∼0.05 a.u. (∼60 eV). Therefore, the H - ion production rate can be increased for a negative ion source configuration that implements the oblique exit angle of hydrogen.

I K Gainullin

V G Dudnikov

Theoretical investigation of the negative ionization of hydrogen particles on metal surfaces with low work function

金属表面低功函数下氢粒子负离子化的理论研究

Abstract The spectral emissions from a microplasma have been used to predict the CO 2 concentration in gas samples covering a concentration range of 0%–100%. Different models based on partial least squares have been evaluated, comparing two different spectral pre-processing filters –multiplicative scatter correction (MSC) and standard normal variate correction (SNV) – and three different wavelength ranges. The models were compared with respect to accuracy, precision, stability and linearity. CO 2 samples were mixed with either air or nitrogen. The choice of mixing gas influenced the predicted concentration and basing the models on data from only one mixing gas resulted in higher prediction power. Using air as mixing gas and SNV filtering resulted in a root mean square error of prediction (RMSEP) of 0.03 for an independent test dataset. This RMSEP was of the same range as the experimental error. On the other hand, the models with the best long term stability, reaching the lowest Allan variance, were based on observations with both mixing gases. Models based on MSC filtering generally had slightly higher RMSEP than those based on SNV filtering. Generally, the CO 2 concentration could be accurately predicted in the concentration range of 5%–90%. For higher and lower concentrations, the models underestimated the CO 2 concentration and were less accurate and precise. Basing the models on fewer wavelengths resulted in reduced linearity. The models were also evaluated by applying them for transcutaneous blood gas monitoring, where they helped to reveal new physiological information.

Lena Klintberg

Erika Åkerfeldt

Anders Persson

Partial least squares modelling of spectroscopic data from microplasma emissions for determination of CO<sub>2</sub> concentration

微等离子体发射光谱数据的偏最小二乘建模用于二氧化碳浓度测定

Abstract In this paper we have discussed the consequence of superthermal electrons and negative ion concentration on the arbitrary amplitude ion-acoustic double layers (IA-DLs) for plasma comprising the hot negative and positive ions with kappa distribution electrons. The energy equation is deduced for ion acoustic waves using Pseudo potential technique. We have investigated different parametric regimes for the existence of rarefactive and compressive ion acoustic DLs. The existence of double layers in term of minimum and maximum Mach number has calculated numerically. The effect of spectral index k on the amplitude of DLs and depth of Sagdeev potential has been discussed in detail. From numerical analysis, it is found that the compressive DLs exist at low values of α and rarefactive double layer exist at higher values of α. On the other hand, the effect of ionic temperature ratio ( σ 1 and σ 2 ) plays significant role for the formation of double layer. Our analytical work also shows that the system supports coexistence of compressive and rarefactive DLs. It is also observed that the mass ratio <?CDATA $\left(\mu \right)$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mfenced close=")" open="(" separators=""> <mml:mrow> <mml:mi>μ</mml:mi> </mml:mrow> </mml:mfenced> </mml:math> affect the basic properties of DLs. We expect that the present results may be used to explain the ion-acoustic double layer in space plasma, where two ionic species and superthermal electrons are observed NO52.35g.

Kishan Kumar

M K Mishra

Arbitrary amplitude ion acoustic double layer in plasma with k-distributed electrons and negative ions

等离子体中具有k分布电子和负离子的任意振幅离子声双层

Abstract The solitonic and quasiperiodic structures of dust acoustic (DA) waves are investigated in a three components quantum dusty plasma composed of mobile negative dust grains, ions, and inertialess electrons. The reductive perturbation method is employed to derive A deformed Korteweg–de Vries (dKdV) equation in planar and nonplanar geometries, and its numerical solutions are obtained using the two level finite difference approximation method. The influence of geometries on DA solitons is discussed. It is observed that in nonplanar geometries, DA solitons travel at different speeds in comparison to one-dimensional planar ones. Furthermore, in the planar geometry, the bifurcation of DA traveling waves has been analyzed on the framework of the dKdV equation. By adding an external periodic force to the derived dKdV equation, the quasiperiodic behaviors of DA waves are presented.

Elham Emadi

Hossein Zahed

Study of cylindrical and spherical dust acoustic solitons and quasiperiodic structures in a quantum dusty plasma

量子尘埃等离子体中圆柱形和球形尘埃声孤子和准周期结构的研

Abstract In the present work, we study the physicochemical changes that arise in water named plasma processed water (PPW) when it is exposed to the downstream low-pressure discharge of ammonia (NH 3 ) gas. Optical emission spectroscopy and voltage-current characteristics of NH 3 plasma are studied to identify species formed in NH 3 plasma along with plasma characterization. A three-way full factorial design of experiment is performed to study the effect of process parameters named applied voltage, post-discharge gas-water interaction time, and NH 3 gas pressure on physicochemical properties of PPW. The obtained results are analyzed using analysis of variance, standardized effect estimation, regression analysis, and response surfaces. The optimum values of these properties and PPW process parameters are estimated using MATLAB fmincon solver with experimental constraints. The emission spectrum of NH 3 plasma showed strong intensity N 2 + lines along with weak intensity N 2 , NH, and N + lines. The obtained results showed the post-discharge gas-water interaction time and applied voltage had a significant impact on physicochemical properties and ammonium ions concentration in PPW. The obtained optimum value of voltage and time is 550 V and 15 min with given experimental constraints.

Vikas Rathore

Vyom Desai

Nirav I. Jamnapara

Sudhir Kumar Nema

Activation of water in the downstream of low-pressure ammonia plasma discharge

低压氨等离子体放电下游水激活

Abstract Plasma discharges can be transient and randomly distributed where a few investigations have been carried out using laser-induced fluorescence to capture snapshots of plasma-produced radicals in the near vicinity of the discharge. Radical distribution dynamics, however, are challenging to study in situ with high spatial and temporal resolution to fully capture the interactions between the discharge and the gas. We here demonstrate a planar laser-induced fluorescence method that can capture molecular distributions of ground state hydroxyl radicals in a discharge plasma and follow how the distribution develops in time with a repetition rate of 27 kHz. The technique is demonstrated by monitoring, in real-time, how the tube-like distribution of ground state OH radicals, surrounding a gliding arc plasma, is affected by flow dynamics and how it develops as the high voltage is turned off at atmospheric pressure. The method presented here is an essential tool for capturing radical-distribution dynamics in situ of chemically active environments which is the active region of the plasma induced chemistry.

Z Wang

P Stamatoglou

C Kong

J Gao

Y Bao

M Aldén

A Ehn

M Richter

Hydroxyl radical dynamics in a gliding arc discharge using high-speed PLIF imaging

滑移弧放电中羟基自由基动力学的高速PLIF成像研究

Abstract Plasma electromagnetic (EM) kinetic simulation faces two unavoidable difficulties. One arises from the fact that Maxwell equations determine a simultaneity relation between transverse electric field <?CDATA ${\vec{E}}_{{Tr}}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mover accent="true"> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mo>⃗</mml:mo> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi mathvariant="italic">Tr</mml:mi> </mml:mrow> </mml:msub> </mml:math> and local growth rates of probability distribution function (PDF) <?CDATA $f$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>f</mml:mi> </mml:math> in Vlasov-Maxwell (V-M) simulation in Eulerian approach, so does that between <?CDATA ${E}_{{Tr}}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="italic">Tr</mml:mi> </mml:mrow> </mml:msub> </mml:math> and Lagrangian particles’ time-varying rates which refers to displacement of <?CDATA $f$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>f</mml:mi> </mml:math> -element in <?CDATA $6D$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>6</mml:mn> <mml:mi>D</mml:mi> </mml:math> phase space in V-M simulation in Lagrangian approach, and macroparticles’ accelerating rates in Particle-in-Cell (PIC) simulation. These simultaneous with <?CDATA ${E}_{{Tr}}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="italic">Tr</mml:mi> </mml:mrow> </mml:msub> </mml:math> are termed as bottom objects’ growth rates (BOGRs) in this work. Directly solving the BOGRs needs to diagonalize a large full matrix, and hence often be approximated. The other arises from the fact that Lagrangian particles’ time-histories should uniformly converge with respect to the time-step. This severe requirement is difficult to be satisfied and hence some of Lagrangian particles’ time-histories lose fidelity. We propose a strict alternative method free from two difficulties. The initial-value problem of V-M system can be interpreted by <?CDATA $6D$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>6</mml:mn> <mml:mi>D</mml:mi> </mml:math> phase space allowed deformation of an initial <?CDATA $f$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>f</mml:mi> </mml:math> -profile. By virtue of a more compact description of <?CDATA $f,$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>f</mml:mi> <mml:mo>,</mml:mo> </mml:math> in which a conditional probability density function (C-PDF) well reflects some macroscopic conservation laws behind the V-M system, we can interpret the initial-value problem of <?CDATA $f$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>f</mml:mi> </mml:math> in terms of <?CDATA $6D$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>6</mml:mn> <mml:mi>D</mml:mi> </mml:math> standing-wave oscillation in the C-PDF. A key subtle difference between microscopic scalar field and microscopic vector field can also lead to a similar scheme of particle simulation. PACS: 52.65.-y.

H Lin

C P Liu

6D phase space collective modes in Vlasov-Maxwell system

Vlasov-Maxwell系统中的6D相空间集体模式

Abstract The objective of this study is to analyse instabilities and growth rate in unmagnetized dense non-relativistic collisionless quantum plasma under the impact of dynamics of ions. Model of quantum hydrodynamics is used to observe the streaming instabilities in highly dense inhomogeneous unmagnetized quantum plasma at low temperature. The model includes continuity and momentum equations for degenerate electrons and nondegenerate ions which interact with each other due to electrostatic field. Using normal mode analysis and linearization, perturbed potential is obtained in terms of unperturbed parameters with the help of first order perturbation in densities and velocities of electrons and ions while neglecting higher order perturbations. Variation in growth rates for detected instabilities is observed by using appropriate quantum plasma parameters.

ISSN	2516-1067
h-index	10

Publication Information	Publisher: IOP Publishing Ltd.，Publishing cycle: ，Journal Type: journal，Open Access Journals: No
Basic data	Year of publication: 2019，Proportion of original research papers: 0.00%，Self Citation Rate:N.A.， Gold OA Rate: 0.00%

Plasma Research Express

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Impact of hot electrons on optical excitation of terahertz radiation by beating of supergaussian lasers in electron-positron collisional plasma

Fano resonance of air-Si waveguide cavity

Theoretical investigation of the negative ionization of hydrogen particles on metal surfaces with low work function

Partial least squares modelling of spectroscopic data from microplasma emissions for determination of CO₂ concentration

Arbitrary amplitude ion acoustic double layer in plasma with k-distributed electrons and negative ions

Study of cylindrical and spherical dust acoustic solitons and quasiperiodic structures in a quantum dusty plasma

Activation of water in the downstream of low-pressure ammonia plasma discharge

Hydroxyl radical dynamics in a gliding arc discharge using high-speed PLIF imaging

6D phase space collective modes in Vlasov-Maxwell system

Two stream instabilities in unmagnetized nonrelativistic quantum plasma

Plasma Research Express

Journal Citation Format

A journal article with 1 author

A journal article with 2 authors

A journal article with 3 authors

A journal article with 5 or more authors

Books Citation Format

Thesis Citation Format

Web sites Citation Format

Patent Citation Format

Staying up late manually editing references? ivySCI automatically matches journals and helps you generate references with a single click.

Share Submission Experience

Impact of hot electrons on optical excitation of terahertz radiation by beating of supergaussian lasers in electron-positron collisional plasma

Fano resonance of air-Si waveguide cavity

Theoretical investigation of the negative ionization of hydrogen particles on metal surfaces with low work function

Partial least squares modelling of spectroscopic data from microplasma emissions for determination of CO2 concentration

Arbitrary amplitude ion acoustic double layer in plasma with k-distributed electrons and negative ions

Study of cylindrical and spherical dust acoustic solitons and quasiperiodic structures in a quantum dusty plasma

Activation of water in the downstream of low-pressure ammonia plasma discharge

Hydroxyl radical dynamics in a gliding arc discharge using high-speed PLIF imaging

6D phase space collective modes in Vlasov-Maxwell system

Two stream instabilities in unmagnetized nonrelativistic quantum plasma

Partial least squares modelling of spectroscopic data from microplasma emissions for determination of CO₂ concentration