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The effect of positive/negative ion on the dust grain charging process in a Vasyliunas-Cairns (VC)-distributed dusty plasma system

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Plasma science and Technology 2019年第6期21卷 58-62页

作者： n AHmAD A A ABID Y AL-HADEETHI m n s qureshi saqib REHmAn Department of Engineering and Applied Physics University of Science and Technology of China Hefei 230026 People's Republic of China CAs Key Laboratory of Geospace Environment Department of Geophysics and Planetary ScienceUniversity of Science and Technology of China Hefei 230026 People's Republic of China Department of Physics Faculty of Sciences King Abdulaziz Unniversity Jeddah 21589 Saudi Arabia Department of Physics GC University Lahore 54000 Pakistan Department of Chemical Physics University of Science and Technology of China Hefei 230026People's Republic of China

Charging mechanism of dust particles has been considered as a growing research area in dusty plasma physics because of its exciting *** this paper,we consider a low-temperature non-equilibrium multispecies plasma model,which consists of Vasyliunas-Caims (VC) distributed electrons,negative/positive streaming ions,and negatively-charged dust grains to explain the charging mechanism of dust *** main theme of this work is to derive expressions of currents for negatively-charged dust grains (considering an equilibrium state position) in the plasma environment comprised of electrons and positive/negative streaming ions using the VC distribution *** proposed model shows that the dust grain surface potential is significantly affected by different plasma parameters such as the negative ion streaming velocity (sn),positive ion streaming velocity (si),spectral indices of VC distribution,negative ion charging state (Zn),positive ion charging state (Zi),and negative ion number density (ρ).

关键词： dust grain surface potential vasyliunas-cairns power law velocity distribution function multi species plasma

A model for Periodic nonlinear Electric Field structures in space Plasmas

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Communications in Theoretical Physics 2009年第7期52卷 149-154页

作者： m.n.s. qureshi sHI Jian-Kui LIU Zhen-Xing Department of Physics GC University Lahore 54000 Pakistan state Key Laboratory of space Weather CSSAR Chinese Academy of Sciences Beijing 100080 China

In this study,we present a physical model to explain the generation mechanism of nonlinear periodic waveswith a large amplitude electric field structures propagating obliquely and exactly parallel to the magnetic ***'sagdeev potential' from the mHD equations is derived and the nonlinear electric field waveforms are obtained when themach number,direction of propagation,and the initial electric field satisfy certain plasma *** the parallelpropagation,the amplitude of the electric field waves with ion-acoustic mode increases with the increase of initial electricfield and mach number but its frequency decreases with the increase of mach *** amplitude and frequency ofthe electric field waves with ion-cyclotron mode decrease with the increase of mach number and become less spiky,andits amplitude increases with the increase of initial electric *** the oblique propagation,only periodic electric fieldwave with an ion-cyclotron mode obtained,its amplitude and frequency increase with the increase of mach number andbecome *** our model the electric field structures show periodic,spiky,and saw-tooth behaviours correspondingto different plasma conditions.

关键词： nonlinear waves electric field solitary structures

Effect on Landau damping rates for a non-maxwellian distribution function consisting of two electron populations

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Chinese Physics B 2013年第3期22卷 358-365页

作者： m.n.s.qureshi s.sehar H.A.shah J.B.Cao space science Institute Beihang University Department of Physics Government College University

In many physical situations where a laser or electron beam passes through a dense plasma,hot low-density electron populations can be generated,resulting in a particle distribution function consisting of a dense cold population and a small hot *** of such low-density electron distributions can alter the wave damping rate.A kinetic model is employed to study the Landau damping of Langmuir waves when a small hot electron population is present in the dense cold electron population with non-maxwellian distribution *** of plasma from maxwellian distributions significantly alters the damping rates as compared to the maxwellian *** damping is found for highly nonmaxwellian distributions as well as plasmas with a higher density and hot electron *** of weak damping is also established when the distribution contains broadened flat tops at the low energies or tends to be *** results may be applied in both experimental and space physics regimes.

关键词： Landau damping Langmuir waves two electron populations non-maxwellian distribution function

Clarification on Polarity of Bipolar Electric Field solitary structures in space Plasmas with satellite Observation

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Chinese Physics Letters 2011年第2期28卷 164-167页

作者： m.n.s.qureshi sHI Jian-Kui Klaus Torkar LIU Zhen-Xing Department of Physics GC UniversityLahore 54000Pakistan state Key Laboratory of space Weather Centre for Space Science and Applied Research(CSSAR)Chinese Academy of SciencesBeijing 100190 space Research Institute Austrian Academy of SciencesA-8042GrazAustria

The bipolar electric field solitary(EFs)structures observed frequently in space plasmas by satellites have two different polarities,first positive electric field peak then negative(i.e.,positive/negative)and first negative then positive peak(i.e.,negative/positive).We provide the physical explanation on the polarity of observed bipolar EFs structures with an electrostatic ion fluid *** results show that if initial electric field𝐸E_(0)>0,the polarity of the bipolar EFs structure will be positive/negative;and if𝐸E_(0)s structure will be negative/***,for a fixed polarity of the EFs,either positive/negative or negative/positive,if the satellite is located at the positive side of the EFs,the observed polarity should be positive/negative,if the satellite is located at the negative side of the EFs,the observed polarity should be negative/***,we provide a method to clarify the natural polarity of the EFs with observed polarity by *** results are significant to understand the physical process in space plasma with the satellite observation.

关键词： Observation polarity bipolar

Dust-Lower-Hybrid surface Waves in Classical and Degenerate Plasmas

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Communications in Theoretical Physics 2013年第11期60卷 623-629页

作者： m.Ayub H.A.shah m.n.s.qureshi m.salimullah Department of Physics G. C. University Department of Physics Mirpur University of Science and Technology (MUST) Department of Physics Jahangirnagar University

The dispersion relation for general dust low frequency electrostatic surface waves propagating on an interface between a magnetized dusty plasma region and a vacuum is derived by using specular reflection boundary conditions both in classical and quantum regimes. The frequency limit ω ≤ωei ≤ ωce is considered and the dispersion relation for the Dust-Lower-Hybrid surface Waves （DLHsW＇s） is derived for both classical and quantum plasma half-space and analyzed numerically. It is shown that the wave behavior changes as the quantum nature of the problem is considered.

关键词： dusty plasma lower hybird surface wave degenerate plasma

Influence of Generalized （r, q） Distribution Function on Electrostatic Waves

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Communications in Theoretical Physics 2006年第3期45卷 550-554页

作者： m.n.s. qureshi sHI Jian-Kui mA shi-Zhuang Key Laboratory of space Weather the Chinese Academy of Sciences Beijing 100080 China Department of Physics Government College University~ Lahore 54000~ Pakistan Graduate University of the Chinese Academy of sciences Beijing 100049 China

non-maxwellian particle distribution functions possessing high energy tail and shoulder in the profile of distribution function considerably change the damping characteristics of the waves. In the present paper Landau damping of electron plasma （Langmuir） waves and ion-acoustic waves in a hot, isotropic, unmagnetized plasma is studied with the generalized （r, q） distribution function. The results show that for the Langmuir oscillations Landau damping becomes severe as the spectral index r or q reduces. However, for the ion-acoustic waves Landau damping is more sensitive to the ion temperature than the spectral indices.

关键词： generalized (r q) distribution function electrostatic waves damping

Dust particle surface potential in an argonhelium plasma using the(r,q)-distribution function

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Communications in Theoretical Physics 2024年第9期76卷 141-148页

作者： Bahaaudin m Raffah A A Abid Abdullah Khan Amin Esmaeili Yas Al-Hadeethi m n s qureshi Department of Physics Faculty of SciencesKing Abdulaziz UniversityJeddah 21589Saudi Arabia Lithography in Devices Fabrication and Development Research Group Deanship of Scientific ResearchKing Abdulaziz UniversityJeddah 21589Saudi Arabia Joint Laboratory of Plasma Application Technology Institute of Advanced TechnologyUniversity of Science and Technology of ChinaHefei230026China CAs Key Laboratory of Geospace Environment University of Science and Technology of ChinaHefei230026China Department of Physics Zhejiang Normal UniversityJinhua321005China Department of Physics Graduate School of ScienceTokyo Metropolitan UniversityMinami-Osawa 1-1Hachioji City192-0397Japan Department of Physics GC UniversityLahore 54000Pakistan

In this paper,the dust particle surface potential for argon-helium plasma is evaluated analytically and numerically in the context of negatively charged dust particles by employing a power-law(r,q)-distribution *** studies have reported the argon-helium plasma and conducted a brief theoretical and experimental *** deepen our understanding further,this study aims to analyze the argon-helium plasma comprehensively using the same pattern but with the(r,q)-distribution *** this purpose,the current balance equations are derived for electron,helium and argon ions,when these charge species attain the quasineutrality *** numerically examined the currents of plasma species for a broad range of effective distribution function parameters r and *** is revealed that the surface potential of dust particles is significantly affected by the parameters r and q,helium ion-to-electron temperature ratio,argon ion-to-electron temperature ratio,and helium ion to argon ion number density *** incorporating the multi-ion(argon-helium)species,the significance of low-temperature nonmaxwellian dusty(complex)plasma is briefly examined.

关键词： dusty plasma dust charge potential plasma physics helium argon plasma r q distribution function non-maxwellian distribution

nonlinear Landau damping of high frequency waves in non-maxwellian plasmas

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Chinese Physics B 2013年第11期22卷 385-389页

作者： m.n.s.qureshi sumbul sehar J.K.shi H.A.shah Department of Physics GC University Center for space science and Applied Research Chinese Academy of Sciences

space plasmas often possess non-maxwellian distribution functions which have a significant effect on the plasma waves. When a laser or electron beam passes through a dense plasma, hot low density electron populations can be generated to alter the wave damping/growth rate. In this paper, we present theoretical analysis of the nonlinear Landau damping for Langmuir waves in a plasma where two electron populations are found. The results show a marked difference between the maxwellian and non-maxwellian instantaneous damping rates when we employ a non-maxwellian distribution function called the generalized （r, q） distribution function, which is the generalized form of the kappa and maxwellian distribution functions. In the limiting case of r = 0 and q→∞, it reduces to the classical maxwellian distribution function, and when r = 0 and q→k ＋1, it reduces to the kappa distribution function.

关键词： nonlinear Landau damping non-maxwellian distribution function nonlinear Langmuir waves,wave-particle interaction

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顶部电离层中双极电场特性研究(英文)

顶部电离层中双极电场特性研究(英文)