Plasma Research Express最新文献_第9页

Linear analysis of bump on tail instability with non-Maxwellian distribution function 非麦克斯韦分布函数下碰撞对尾翼不稳定性的线性分析

Plasma Research Express Pub Date : 2020-04-28 DOI: 10.1088/2516-1067/ab8e2b

N. Noreen, A. Shiekh, I. Habumugisha, S. Zaheer, H. Shah

引用次数: 0

Numerical studies on the effects of operating parameters on the behaviour of transferred arc inside the crucible with gas injection through the cathode at different operating pressures 操作参数对不同操作压力下阴极气体注入坩埚内转移电弧行为影响的数值研究

Plasma Research Express Pub Date : 2020-04-24 DOI: 10.1088/2516-1067/ab89c9

Lintu G Laly, K. Ramachandran

{"title":"Numerical studies on the effects of operating parameters on the behaviour of transferred arc inside the crucible with gas injection through the cathode at different operating pressures","authors":"Lintu G Laly, K. Ramachandran","doi":"10.1088/2516-1067/ab89c9","DOIUrl":"https://doi.org/10.1088/2516-1067/ab89c9","url":null,"abstract":"Hollow cathode with gas injection in transferred arc plasma system has been used for high temperature material processes. The effect of operating parameters such as gas flow rate, electrode gap, arc current, etc on the arc behaviour at an operating pressure of 1 atm is studied numerically. The knowledge on the arc behaviour at operating pressures lower and higher than atmospheric pressure is very limited. In this work, a two dimensional axi-symmetric model is developed to simulate the behaviour of the argon arcs formed between hollow cathode with gas injection and crucible anode as well as heat transfer from the plasma to the anode at different operating pressures. The effects of gas flow rate and electrode gap on the arc behaviour and heating efficiency at different operating pressures are investigated. The arc voltage is strongly influenced by both operating pressure and electrode gap. The effect gas flow rate on the arc voltage is stronger at higher operating pressures. The movement or detachment of the arc root from the centre of the anode is strongly influenced by operating pressure and gas flow rate. Arcs formed at 0.2 atm have unique features compared to the arcs formed at higher operating pressures. The heat flux to the anode is higher where arc root is attached and the highest arc heating efficiency of 68.1% is predicted at an operating pressure of 0.2 atm, electrode gap of 15 mm and gas flow rate of 5 lpm.","PeriodicalId":36295,"journal":{"name":"Plasma Research Express","volume":"30 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/2516-1067/ab89c9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41302677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Pulsed fusion grade deuterium plasma induced structural phase transformation in stainless steel using medium energy plasma focus device 利用中能等离子体聚焦装置，脉冲聚变级氘等离子体诱导不锈钢发生组织相变

Plasma Research Express Pub Date : 2020-04-23 DOI: 10.1088/2516-1067/ab835d

R. Niranjan, R. Srivastava, J. Joycee, P. Mishra, K. Joshi

{"title":"Pulsed fusion grade deuterium plasma induced structural phase transformation in stainless steel using medium energy plasma focus device","authors":"R. Niranjan, R. Srivastava, J. Joycee, P. Mishra, K. Joshi","doi":"10.1088/2516-1067/ab835d","DOIUrl":"https://doi.org/10.1088/2516-1067/ab835d","url":null,"abstract":"Samples of ferrite -austenite stainless steel (SS) have been exposed to fusion grade plasma and radiations using a medium energy plasma focus device, ‘MEPF-12’. Three different polished samples of SS (10 mm diameter ×2 mm thick) were irradiated using single and multiple ( five and ten) plasma focus discharges. Each plasma focus discharge comprised energetic and high intensity deuterium ions, energetic deuterium plasma streams and 2.45 MeV neutrons produced via D(d, 3He)n fusion reactions. At sample position, typical values of deuterium ion fluence and neutron fluence were measured to be ∼1018ions/m2 and ∼1010 neutrons/m2, respectively, in each plasma focus discharge. Post irradiations, the samples have been characterized using different techniques for study of their surface modification characteristics, specifically, crystallinity, surface morphologies and surface roughness. The XRD analysis of the SS sample exposed to single or more plasma focus discharges revealed structural phase transformation from initial mixed ferrite [α(BCC)] -austenite [γ(FCC)] phase to austenite phase. Effects of deuterium ion concentration and transient rise in surface temperature on structural phase transformation have been discussed in detail. Surface morphologies studied using SEM has revealed erosion, melting and recrystallization of surface layer along with various other defects like pores, blisters, open bubbles and so on. Measurements using surface profilometer confirmed increase in surface roughness of the samples on irradiation. Detail discussion on the variation in the surface damage features with increasing number of plasma focus discharges used for irradiating samples and its comparison with virgin sample have been included in this report.","PeriodicalId":36295,"journal":{"name":"Plasma Research Express","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/2516-1067/ab835d","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44286744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The correct cutoff for Rutherford scattering cross-section 卢瑟福散射截面的正确截止

Plasma Research Express Pub Date : 2020-04-16 DOI: 10.1088/2516-1067/ab880b

Yongbin Chang, Dingyi Li

{"title":"The correct cutoff for Rutherford scattering cross-section","authors":"Yongbin Chang, Dingyi Li","doi":"10.1088/2516-1067/ab880b","DOIUrl":"https://doi.org/10.1088/2516-1067/ab880b","url":null,"abstract":"The correct cutoff variable for the integrals with Rutherford scattering cross-section is established in this paper. The traditional cutoff variables in plasma physics, such as scattering angle θ and impact parameter b, are incorrect or just partial cutoff variables for lacking the necessary cutoff on relative speed g. The correct cutoff variable is the same variable that correctly describing the singularity of the integrals. The difference of the partial cutoff variables and the correct one is compared through their contour lines in the b − g plane. With the correct cutoff, many physical results become more simplified and structured for both rigid-sphere interaction and Coulomb interaction. These physical results include the arbitrary higher order of Fokker-Planck coefficients, transition moments, and energy transfer rates for both rigid-sphere and Coulomb interactions. All the physical results depending on velocity are expressed by a set of functions q n ( k ) ( y min , u ) = 2 π ∫ y min ∞ ∫ − 1 1 e − y + xu 2 y n − x k dxdy . A useful integral formula ∫ 0 ∞ q n ( k ) ( y min , u ) u k + 2 e − u 2 ξ du = ξ k + 3 2 2 1 + ξ k − n 2 ∑ j = 0 ⌊ k / 2 ⌋ k ! Γ n + k + 1 2 − j , y min 2 1 + ξ j ! ( k − 2 j ) ! 4 ξ j , which associates q n ( k ) ( y min , u ) with incomplete gamma functions Γ j , y min 2 1 + ξ is also proved. This integral formula is the key to show that the correct cutoff constants for both rigid-sphere and Coulomb interactions are all in the form of incomplete gamma functions of different orders. In particular, the so called Coulomb logarithm ln Λ should be replaced by the exact form—the zeroth order incomplete Gamma function.","PeriodicalId":36295,"journal":{"name":"Plasma Research Express","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/2516-1067/ab880b","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49054359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Peculiar behavior of the instability in systems with weak electron beam-plasma coupling 弱电子束等离子体耦合系统不稳定性的特殊行为

Plasma Research Express Pub Date : 2020-04-06 DOI: 10.1088/2516-1067/ab8076

E. Rostomyan

{"title":"Peculiar behavior of the instability in systems with weak electron beam-plasma coupling","authors":"E. Rostomyan","doi":"10.1088/2516-1067/ab8076","DOIUrl":"https://doi.org/10.1088/2516-1067/ab8076","url":null,"abstract":"A study is developed, which allows investigating weakly coupled electron beam-plasma systems in general form regardless on geometry and specific parameters. In this case the instability acquires completely new aspects. In contrast to the well-known case of strong coupling, the role of the beam natural oscillations becomes decisive. The instability is due to the growth of the beam wave of negative energy. The study shows that the space-time evolution of an initial perturbation in weakly coupled beam-plasma systems is described by partial differential equation of second order. The equation is solved. Obtained expression for the fields’ space-time distribution gives most complete information on the instability: growth rates, velocities of unstable perturbations, influence of the dissipation on the instability, its character, (absolute/convective), etc. Most of the information is unavailable by conventional methods. In particular, the results clearly show that with an increase in the level of dissipation in the plasma, the instability transforms into a new, previously unknown type of dissipative streaming instability (DSI). Its growth rate depends on dissipation more critically than the growth rate of the single known DSI.","PeriodicalId":36295,"journal":{"name":"Plasma Research Express","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44603934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

A study of Chandrasekhar limits in adiabatic degenerate plasmas with superthermal ions 热离子绝热简并等离子体的钱德拉塞卡极限研究

Plasma Research Express Pub Date : 2020-03-24 DOI: 10.1088/2516-1067/ab805a

M. M. Haider, S. Yasmin Swarna, Nusrat Khan, O. Rahman

引用次数: 3

Head-on collision of ion-acoustic solitons in collisional pair ions plasmas with non-Maxwellian electrons 离子声孤子在非麦克斯韦电子碰撞对离子等离子体中的头碰撞

Plasma Research Express Pub Date : 2020-03-18 DOI: 10.1088/2516-1067/ab7c82

Meraj Alam, M. Talukder

{"title":"Head-on collision of ion-acoustic solitons in collisional pair ions plasmas with non-Maxwellian electrons","authors":"Meraj Alam, M. Talukder","doi":"10.1088/2516-1067/ab7c82","DOIUrl":"https://doi.org/10.1088/2516-1067/ab7c82","url":null,"abstract":"The head-on collisional phenomena concerning ion acoustic waves are investigated considering collisional plasma system comprises of pair ions and hybrid non-Maxwellian electrons. The two-sided Korteweg–de Vries (KdV) equations are derived using extended poincaré-Lighthill-Kuo (ePLK) method. The effects of superthermal index ( κ e ) related to kappa distributed electrons, nonthermal parameter ( β e ) related to the Cairn’s distributed electrons, density ratio of electron to positive ion ( n e 1 i ), and temperature ratio ( T 1 i 2 i ) of positive to negative ion on the phase velocity, spatiotemporal evolutions of amplitude, width, time dependent phase shifts and velocity of the right propagating solitons as well as the production of KdV solitons are investigated. Both the rarefactive and compressive soliton structures are produced due to head-on collision depending on plasma parameters. It is found that phase velocity is increasing (decreasing) due to the enhancement of κ e and β e ( n e 1 i ). The amplitude of right traveling soliton increases (decreases) with increasing β e ( κ e ), while κ e and β e show opposite characteristic behaviors due to the plasma parameters concerned.","PeriodicalId":36295,"journal":{"name":"Plasma Research Express","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/2516-1067/ab7c82","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42523585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Exact irreducible moments of the Landau collision operator in the random-velocity moment expansion 随机速度矩展开中朗道碰撞算子的精确不可约矩

Plasma Research Express Pub Date : 2020-03-18 DOI: 10.1088/2516-1067/ab7d0f

J. Ji, J. Spencer, E. Held

引用次数: 1

The effect of a second grounded electrode on the atmospheric pressure argon plasma jet 第二接地电极对大气压氩等离子体射流的影响

Plasma Research Express Pub Date : 2020-03-06 DOI: 10.1088/2516-1067/ab7b36

A. Mohamed, Mazen Mohamed Aljuhani, J. Almarashi, A. Alhazime

{"title":"The effect of a second grounded electrode on the atmospheric pressure argon plasma jet","authors":"A. Mohamed, Mazen Mohamed Aljuhani, J. Almarashi, A. Alhazime","doi":"10.1088/2516-1067/ab7b36","DOIUrl":"https://doi.org/10.1088/2516-1067/ab7b36","url":null,"abstract":"Cold atmospheric pressure plasma jet has attracted a great interest of researchers engaged in different areas due to its wide range of applications. In this article, the effect of adding a second grounded electrode (SGE) to the two electrodes plasma jet system was investigated. The jets system consisted of a quartz tube surrounded by two copper strips, which were separated by 40 mm. The SGE was placed below the jet nozzle by 2 mm and 5 mm from its axial. The jet characteristics with and without the SGE were investigated using plasma images, voltage-current waveforms, and emission spectra. Two current pulses per each half a cycle were measured when the SGE was used while one pulse was measured without using it. The second current pulse was much longer than the first one. Argon emission spectra were the most intense lines among all other plasma species even for the measurement out of the flow stream. The OH• emission spectra were higher in the discharge zone than those outside the discharge zone. The presence of the SGE enhanced the emission spectra for all the investigated positions above and in front of the SGE. The transition from laminar to turbulent mode was observed at lower flow rate value without using the SGE and a significant decrease in jet length was detected at 3.5 slpm with and without using the SGE. This system is scalable by using multi-SGE to form a large volume plasma, which is strongly required for biomedical and industrial applications.","PeriodicalId":36295,"journal":{"name":"Plasma Research Express","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/2516-1067/ab7b36","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43033916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Oblique propagation of nonlinear solitary structures in electron positron ion plasmas under the influence of quantizing magnetic field 量子化磁场影响下电子-正电子-离子等离子体中非线性孤立结构的斜向传播

Plasma Research Express Pub Date : 2020-03-06 DOI: 10.1088/2516-1067/ab7ab8

S. Hussain, N. Imtiaz, H. Hasnain

引用次数: 2