Showing papers in "Journal of Plasma Physics in 2011"
TL;DR: The complexity and the diversity of the field of dusty plasma physics are briefly discussed in this paper, where the basic features of dusty plasmas, particularly basic characteristics of dust in a plasma, and typical dusty plasma parameters for different space and laboratory plasma conditions, are presented.
Abstract: The basic features of dusty plasmas, particularly basic characteristics of dust in a plasma, and typical dusty plasma parameters for different space and laboratory plasma conditions, are presented. The complexity and the diversity of the field of dusty plasma physics are briefly discussed. Theoretical and experimental discoveries of linear and nonlinear features of waves, particularly dust-ion-acoustic and dust-acoustic waves, in dusty plasmas are reviewed.
51 citations
TL;DR: In this article, the output characteristics of the electron bunch accelerated by a chirped femtosecond laser pulse in vacuum using linear, elliptical and circular polarization states were investigated.
Abstract: In this paper, we investigated the output characteristics of the electron bunch accelerated by a chirped femtosecond laser pulse in vacuum using linear, elliptical and circular polarization states. To examine the features of the energy and angular spectra, emittances and position distribution of the electron bunch numerically, 105 electrons are used. It is found that the initial emittances of the electron bunch together with a proper choice of the polarization state of the laser pulse could lead to the efficient electron bunch acceleration.
32 citations
TL;DR: In this paper, the authors demonstrate the ~77× amplification of 0.5 to 3.5-ps pulses of seed light by interaction with Langmuir waves in a low density (1.2 × 1019 cm−3) plasma produced by a 1-ns, 230-J, 1054-nm pump beam with 1.2× 1014 W/cm2 intensity.
Abstract: Experiments demonstrate the ~77× amplification of 0.5 to 3.5-ps pulses of seed light by interaction with Langmuir waves in a low density (1.2 × 1019 cm−3) plasma produced by a 1-ns, 230-J, 1054-nm pump beam with 1.2 × 1014 W/cm2 intensity. The waves are strongly damped (kλD = 0.38, Te = 244 eV) and grow over a ~ 1 mm length, similar to what is experienced by scattered light when it interacts with crossing beams as it exits an ignition target. The amplification reduces when the seed intensity increases above ~1 × 1011 W/cm2, indicating that saturation of the plasma waves on the electron kinetic time scale (<0.5 ps) limits the scatter to ~1% of the available pump energy. The observations are in agreement with 2D PIC simulations in this case.
25 citations
TL;DR: In this article, the authors derived a formula for the second order plasma density perturbation in the radial electric field and showed that a second harmonic is generated by convective nonlinearity of both thermal plasma and energetic particles.
Abstract: It is shown that nonlinear self-interaction of energetic particle-driven Geodesic Acoustic Mode does not generate a second harmonic in radial electric field using the fluid model. However, kinetic effects of energetic particles can induce a second harmonic in the radial electric field. A formula for the second order plasma density perturbation is derived. It is shown that a second harmonic of plasma density perturbation is generated by the convective nonlinearity of both thermal plasma and energetic particles. Near the midplane of a tokamak, the second order plasma density perturbation (the sum of second harmonic and zero frequency sideband) is negative on the low field side with its size comparable to the main harmonic at low fluctuation level. These analytic predictions are consistent with the recent experimental observation in DIII-D.
23 citations
TL;DR: In this paper, the authors investigated under which parameter regimes the magnetohydrodynamic (MHD) Rankine-Hugoniot conditions, which describe discontinuous solutions to the MHD equations, allow for slow, intermediate and fast shocks.
Abstract: We investigate under which parameter regimes the magnetohydrodynamic (MHD) Rankine-Hugoniot conditions, which describe discontinuous solutions to the MHD equations, allow for slow, intermediate and fast shocks. We derive limiting values for the upstream and downstream shock parameters for which shocks of a given shock-type can occur. We revisit this classical topic in nonlinear MHD dynamics, augmenting the recent time reversal duality finding by in the usual shock frame parametrization.
22 citations
TL;DR: In this paper, the theory of surface waves propagating across axis of symmetry in non-uniform cylindrical metal waveguides with plasma filling has been studied both analytically and numerically.
Abstract: This paper is devoted to the theory of surface waves propagating across axis of symmetry in non-uniform cylindrical metal waveguides with plasma filling. The presented results are devoted to: first, studying an influence of plasma density non-uniformity on the features of these waves; second, studying an influence of an external magnetic fields' non-uniformity on their dispersion properties; third, studying possibility to sustain gas discharge by propagation of these waves under different operating regimes. The problems have been solved both analytically and numerically. Plasma particles are described in the framework of hydrodynamics; fields of the studied waves are determined by a set of Maxwell equations. Analytical research of the obtained equations is carried out by the method of successive approximation; adequacy of such approach is proved here as well. Numerical evaluations of the possibilities to observe experimentally the phenomena, which accompany propagation of these waves, are carried out.
21 citations
TL;DR: The generalized dispersion equation for superluminal transverse oscillation in an unmagnetized, collisionless, isotropic and relativistic plasma with non-extensive q-distribution is derived in this paper.
Abstract: The generalized dispersion equation for superluminal transverse oscillation in an unmagnetized, collisionless, isotropic and relativistic plasma with non-extensive q-distribution is derived. The analytical dispersion relation is obtained in an ultra-relativistic regime, which is related to q-parameter and temperature. In the limit q → 1, the result based on the relativistic Maxwellian distribution is recovered. Using the numerical method, we obtain the full dispersion curve that cannot be given by an analytic method. It is shown that the numerical solution is in good agreement with the analytical result in the long-wavelength and short-wavelength region for ultra-relativistic plasmas.
20 citations
TL;DR: In this article, the dispersion properties of low-frequency electromagnetic (EM) perturbations in the magnetized core of self-gravitating white dwarf stars with ultra-relativistic degenerate electrons were discussed.
Abstract: We discuss the dispersive properties of low-frequency electromagnetic (EM) perturbations in the magnetized core of self-gravitating white dwarf stars with ultra-relativistic degenerate electrons. For our purposes, we derive a dispersion relation by using the hydrodynamic equations for the ions under the action of EM and self-gravitating forces, and the inertialess electrons under the action of EM forces and the gradient of the ultra-relativistic pressure. The dispersion relation admits stability of a white dwarf star against a class of EM perturbations whose wavelengths are shorter than 15000 km.
19 citations
TL;DR: In this article, the nonlinear coupling of the Alfven wave to acoustic waves is studied, and a set of compressive and coupled-wave equations for the transverse magnetic field and longitudinal electric field is derived for waves propagating along the mean-field direction.
Abstract: Large-amplitude Alfven waves are ubiquitous in space plasmas and a main component of magnetohydrodynamic (MHD) turbulence in the heliosphere. As pump waves, they are prone to parametric instability by which they can generate cyclotron and acoustic daughter waves. Here, we revisit a related process within the framework of the multi-fluid equations for a plasma consisting of many species. The nonlinear coupling of the Alfven wave to acoustic waves is studied, and a set of compressive and coupled-wave equations for the transverse magnetic field and longitudinal electric field is derived for waves propagating along the mean-field direction. It turns out that slightly compressive Alfven waves exert, through induced gyro-radius and kinetic-energy modulations, an electromotive force on the particles in association with a longitudinal electric field, which has a potential that is given by the gradient of the transverse kinetic energy of the particles gyrating about the mean field. This in turn drives electric fluctuations (sound and ion-acoustic waves) along the mean magnetic field, which can nonlinearly react back on the transverse magnetic field. Mutually coupled Alfven-cyclotron--acoustic waves are thus excited, a nonlinear process that can drive a cascade of wave energy in the plasma, and may generate compressive microturbulence. These driven electric fluctuations might have consequences for the dissipation of an MHD turbulence and, thus, for the heating and acceleration of particles in the solar wind.
18 citations
TL;DR: In this paper, it was shown that large-scale ultra low-frequency Rossby and Khantadze electromagnetic waves can propagate in the earth's conductive ionospheric E-region.
Abstract: It is shown that in the earth's conductive ionospheric E-region, large-scale ultra low-frequency Rossby and Khantadze electromagnetic waves can propagate. Along with the prevalent effect of Hall conductivity for these waves, the latitudinal inhomogeneity of both the earth's angular velocity and the geomagnetic field becomes essential. Action of these effects leads to the coupled propagation of electromagnetic Rossby and Khantadze modes. Linear propagation properties of these waves are given in detail. It is shown that the waves lose the dispersing property for large values of wave numbers. Corresponding nonlinear solitary vortical structures are constructed. Conditions for such self-organization are given. It is shown that nonlinear large-scale vortices generate the stronger pulses of the geomagnetic field than the corresponding linear waves. Previous investigations are revised.
17 citations
TL;DR: In this article, the dispersion relation of the plasma waves is determined from a linear stability analysis using a new eigenvalue method that is employed to solve the set of differential wave equations which describe the propagation of plasma waves along the direction of the constant component of the Alfven wave magnetic field.
Abstract: In this paper, we study the weakly-compressive high-frequency plasma waves which are superposed on a large-amplitude Alfven wave in a multi-fluid plasma consisting of protons, electrons, and alpha particles. For these waves, the plasma environment is inhomogenous due to the presence of the low-frequency Alfven wave with a large amplitude, a situation that may apply to space plasmas such as the solar corona and solar wind. The dispersion relation of the plasma waves is determined from a linear stability analysis using a new eigenvalue method that is employed to solve the set of differential wave equations which describe the propagation of plasma waves along the direction of the constant component of the Alfven wave magnetic field. This approach also allows one to consider weak compressive effects. In the presence of the background Alfven wave, the dispersion branches obtained differ significantly from the situation of a uniform plasma. Due to compressibility, acoustic waves are excited and couplings between various modes occur, and even an instability of the compressive mode. In a kinetic treatment, these plasma waves would be natural candidates for Landau-resonant wave–particle interactions, and may thus via their damping lead to particle heating.
TL;DR: In this paper, the basic features of obliquely propagating dust ion-acoustic (DIA) solitary waves in an adiabatic magnetized dusty electronegative plasma (containing Boltzmann electrons, Boltzman negative ions, adiabiabatic positive ions, and negatively charged stationary dust) have been investigated.
Abstract: The basic features of obliquely propagating dust ion-acoustic (DIA) solitary waves in an adiabatic magnetized dusty electronegative plasma (containing Boltzmann electrons, Boltzmann negative ions, adiabatic positive ions, and negatively charged stationary dust) have been investigated. The reductive perturbation method has been employed to derive the Korteweg–de Vries (KdV) equation which admits a solitary wave solution. The combined effects of ion adiabaticity and external magnetic field (obliqueness), which are found to significantly modify the basic features of the small but finite-amplitude DIA solitary waves, are explicitly examined. The implications of our results in space and laboratory dusty plasmas are briefly discussed.
TL;DR: In this article, an approach to the nonlinear inertia term in the momentum equation of the positive ions needed to be accounted for in the free-fall regime of the discharge maintenance was proposed.
Abstract: The study, being on two-dimensional modelling of low pressure discharges, suggests an approach to the nonlinear inertia term in the momentum equation of the positive ions needed to be accounted for in the free-fall regime of the discharge maintenance. On the basis of conclusions that the inertia term acts in the wall sheath, where the ions fly perpendicularly to the walls, it is shown that (i) the parallel – to the walls – velocity component can be neglected, and (ii) the rest of the convective derivative can be determined by using the energy conservation law in the collisionless case. In a way, the inertia term acting as a retarding force is joined to the momentum loss term by introducing effective collision frequencies. The validity of the procedure is proved in a model of a low pressure argon discharge by comparison with the exact solutions for the two-dimensional spatial distribution of the discharge characteristics (ion velocity, electron density and temperature and DC electric field and its potential). The conclusion is that (i) ignoring the velocity component that is parallel to the walls does not cause deviation from the exact solution, and (ii) the approximation of using the energy conservation law in the collisionless case is good enough.
TL;DR: In this paper, the reaction rate probability integral is extended from the Maxwell-Boltzmann approach to a more general approach by using the pathway model introduced by Mathai in 2005.
Abstract: The reaction rate probability integral is extended from Maxwell–Boltzmann approach to a more general approach by using the pathway model introduced by Mathai in 2005 (A pathway to matrix-variate gamma and normal densities. Linear Algebr. Appl. 396 , 317–328). The extended thermonuclear reaction rate is obtained in the closed form via a Meijer's G -function and the so-obtained G -function is represented as a solution of a homogeneous linear differential equation. A physical model for the hydrodynamical process in a fusion plasma-compressed and laser-driven spherical shock wave is used for evaluating the fusion energy integral by integrating the extended thermonuclear reaction rate integral over the temperature. The result obtained is compared with the standard fusion yield obtained by Haubold and John in 1981 (Analytical representation of the thermonuclear reaction rate and fusion energy production in a spherical plasma shock wave. Plasma Phys. 23 , 399–411). An interpretation for the pathway parameter is also given.
TL;DR: In this article, a new equation of motion that governs weakly nonlinear phenomena in ideal magnetohydrodynamics (MHDs) is derived as a natural extension of the well-known linearized equation for the displacement field, made possible by expanding the MHD Lagrangian explicitly up to third order with respect to the displacement of plasma.
Abstract: A new equation of motion that governs weakly nonlinear phenomena in ideal magnetohydrodynamics (MHDs) is derived as a natural extension of the well-known linearized equation of motion for the displacement field. This derivation is made possible by expanding the MHD Lagrangian explicitly up to third order with respect to the displacement of plasma, which necessitates an efficient use of the Lie series expansion. The resultant equation of motion (i.e. the Euler–Lagrange equation) includes a new quadratic force term which is responsible for various mode–mode coupling due to the MHD nonlinearity. The third-order potential energy serves to quantify the coupling coefficient among resonant three modes and its cubic symmetry proves the Manley–Rowe relations. In contrast to earlier works, the coupling coefficient is expressed only by the displacement vector field, which is already familiar in the linear MHD theory, and both the fixed and free boundary cases are treated systematically.
TL;DR: In this article, the existence of stable axially and spherically symmetric plasma structures on the basis of the new nonlinear Schrodinger equation (NLSE) accounting for non-local electron nonlinearities is studied.
Abstract: We study the existence of stable axially and spherically symmetric plasma structures on the basis of the new nonlinear Schrodinger equation (NLSE) accounting for non-local electron nonlinearities. The numerical solutions of NLSE having the form of spatial solitions are obtained and their stability is analyzed. We discuss the possible application of the obtained results to the theoretical description of natural plasmoids in the atmosphere.
TL;DR: In this article, a particle-in-cell numerical simulation of the electron Weibel instability is applied in a frame of Darwin (radiationless) approximation of the self-consistent fields of sparse plasma.
Abstract: A particle-in-cell numerical simulation of the electron Weibel instability is applied in a frame of Darwin (radiationless) approximation of the self-consistent fields of sparse plasma. As a result, we were able to supplement the classical picture of the instability and, in particular, to obtain the dependency of the basic characteristics (the time of development and the maximum field energy) of the thermal anisotropy parameter, to trace the dynamic restructuring of current filaments accompanying the non-linear stage of the instability and to trace in detail the evolution of the initial anisotropy of the electron component of plasma.
TL;DR: In this article, a set of highly nonlinear differential equations for a current sheet in a dusty plasma is presented, similar to that of E. G. Harris, and an analytic solution is found for the depleted electron regime.
Abstract: In 1962 E. G. Harris published a solution to the problem of a current sheet separating regions of oppositely directed magnetic field in a fully ionized plasma. The resulting solution has become known as the ‘Harris sheet’ and has been of great utility to the plasma physics community. In this paper, the footsteps of Harris are retraced with the addition of a multiply charged massive dust component. A set of highly nonlinear differential equations for a current sheet in a dusty plasma are presented. An analytic solution, similar to that of Harris, is found for the depleted electron regime. This solution is of great relevance to many astrophysical and laboratory dusty plasmas. Current sheet thickness and asymptotic field strength are calculated for various dusty plasma environments.
TL;DR: In this paper, a paraxial-like approach was invoked to understand the nature of propagation of a hollow Gaussian beam (HGB) propagating in plasma under the influence of relativistic nonlinearity.
Abstract: A paraxial-like approach has been invoked to understand the nature of propagation of a hollow Gaussian beam (HGB) propagating in plasma under the influence of relativistic non-linearity. In this approach, the parameters are expanded in terms of the radial distance from the maximum of irradiance rather than that from the axis. This paper investigates the excitation of plasma wave in a hot collision less plasma by HGB. On account of the × force, a plasma wave at 2ω0 (here, ω0 is the pump laser frequency) is generated. The solution of the HGB has been obtained within the paraxial ray approximation. Filamentary structures of the laser beam are observed due to relativistic non-linearity.
TL;DR: In this paper, the basic features and multi-dimensional instability of electrostatic solitary waves propagating in an ultra-relativistic degenerate dense magnetized plasma have been investigated by the reductive perturbation method and the small-k perturbations expansion technique.
Abstract: The basic features and multi-dimensional instability of electrostatic solitary waves propagating in an ultra-relativistic degenerate dense magnetized plasma have been investigated by the reductive perturbation method and the small-k perturbation expansion technique. The Zakharov–Kuznetsov (ZK) equation has been derived, and its numerical solutions for some special cases have been analysed to identify the basic features (viz. amplitude, width, instability, etc.) of these electrostatic solitary structures. The implications of our results in some compact astrophysical objects, particularly white dwarfs and neutron stars, have been briefly discussed.
TL;DR: In this paper, the nonlinear propagation of dust ion acoustic solitary waves in a collisional dusty plasma, which consists of negatively charged small dust grains, positively charged ions and isothermal electrons with background neutral particles, is investigated.
Abstract: In the present research paper, the nonlinear propagation of dust ion acoustic solitary waves in a collisional dusty plasma, which consists of negatively charged small dust grains, positively charged ions and isothermal electrons with background neutral particles, is investigated. The low rates compared to the ion oscillation frequency, of the charge-fluctuation dynamics of the dust grains, the ionization, ion-neutral and dust-neutral collisions (i.e. weak dissipations) are considered. Using the reductive perturbation theory, a damped Korteweg-de Vries (DKdV) equation is derived. On the other hand, the dynamics of solitary waves at a critical phase velocity is governed by a damped modified Korteweg-de Vries (DMKdV) equation. The nonlinear properties of dust ion acoustic waves in the presence of weak dissipations in the two cases are discussed.
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TL;DR: In this article, the authors investigated multi-dimensional Alfven simple waves in magnetohydrodynamics (MHD) using Boillat's formalism, where all physical variables (the gas density, pressure, fluid velocity, entropy, and magnetic field in-duction) depend on a single phase function.
Abstract: Multi-dimensional Alfven simple waves in magnetohydrodynamics (MHD) are investigated using Boillat's formalism. For simple wave solutions, all physical variables (the gas density, pressure, fluid velocity, entropy, and magnetic field in- duction in the MHD case) depend on a single phase function ' which is a function of the space and time variables. The simple wave ansatz requires that the wave normal and the normal speed of the wave front depend only on the phase function '. This leads to an implicit equation for the phase function, and a generalisation of the concept of a plane wave. We obtain examples of Alfven simple waves, based on the right eigenvector solutions for the Alfven mode. The Alfven mode solutions have six integrals, namely that the entropy, density, magnetic pressure and the group ve- locity (the sum of the Alfven and fluid velocity) are constant throughout the wave. The eigen-equations require that the rate of change of the magnetic induction B with ' throughout the wave is perpendicular to both the wave normal n and B. Methods to construct simple wave solutions based on specifying either a solution ansatz for n(') or B(') are developed.
TL;DR: In this paper, the evolution of the bump-on-tail instability (BoTI) is studied for plasma subject to one-dimensional mechanical compression, and it is shown that the final state of BoTI differs from that described by quasilinear theory for stationary bulk plasma and can depend on the compression history.
Abstract: Through particle-in-cell simulations, the evolution of the bump-on-tail instability (BoTI) is studied for plasma subject to one-dimensional mechanical compression. It is shown that the final state of BoTI differs from that described by quasilinear theory for stationary bulk plasma and can depend on the compression history. The transformation of thermal energy into wave energy increases the plasma compressibility, thereby decreasing the amount of mechanical work required to compress the plasma to a specified size. Also, the energy spectrum of the excited modes can be tailored by choosing a particular compression scenario, offering a new technique for manipulating plasmas mechanically.
TL;DR: In this paper, the authors developed kinematic models for torsional spine and fan reconnection using both localized η and localized current and compared the non-ideal flows predicted by each.
Abstract: Magnetic reconnection in three dimensions (3D) is a natural extension from X-point reconnection in two dimensions. Of central importance in the 3D process is a localized non-ideal region within which the plasma and magnetic field decouple allowing for field line connectivity change. In practice, localized current structures provide this localization; however, mathematically a similar effect can be achieved with the localization of plasma resistivity instead. Physically though, such approaches are unrealistic, as anomalous resistivity requires very localized currents. Therefore, we wish to know how much information is lost in localizing η instead of current? In this work we develop kinematic models for torsional spine and fan reconnection using both localized η and localized current and compare the non-ideal flows predicted by each. We find that the flow characteristics are dictated almost exclusively by the form taken for the current profile with η acting only to scale the flow. We do, however, note that the reconnection mechanism is the same in each case. Therefore, from an understanding point of view, localized η models are still important first steps into exploring the role of non-ideal effects.
TL;DR: In this paper, the stability of an axisymmetric plasma jet in a parallel magnetic field is solved analytically, in the Wentzel, Kramers, Brillouin (WKB) approximation, for the plasma jet with a boundary in the form of a tangential discontinuity over the radial coordinate.
Abstract: A problem of the stability of an inhomogeneous axisymmetric plasma jet in a parallel magnetic field is solved. The jet boundary becomes, under cer- tain conditions, unstable relative to magnetosonic oscillations (Kelvin-Helmholtz instability) in the presence of a shear flow at the jet boundary. Because of its internal inhomogeneity the plasma jet has resonance surfaces, where conversion takes place between various modes of plasma magnetohydrodynamic (MHD) oscillations. Propagating in inhomogeneous plasma, fast magnetosonic waves drive the Alfven and slow magnetosonic (SMS) oscillations, tightly localized across the magnetic shells, on the resonance surfaces. MHD oscillation energy is absorbed in the neighbourhood of these resonance surfaces. The resonance surfaces disappear for the eigenmodes of SMS waves propagating in the jet waveguide. The stability of the plasma MHD flow is determined by competition between the mechanisms of shear flow instability on the boundary and wave energy dissipation because of resonant MHD-mode coupling. The problem is solved analytically, in the Wentzel, Kramers, Brillouin (WKB) approximation, for the plasma jet with a boundary in the form of a tangential discontinuity over the radial coordinate. The Kelvin-Helmholtz instability develops if plasma flow velocity in the jet exceeds the maximum Alfven speed at the boundary. The stability of the plasma jet with a smooth boundary layer is investigated numerically for the basic modes of MHD oscillations, to which the WKB approximation is inapplicable. A new 'unstable mode of MHD oscillations has been discovered which, unlike the Kelvin-Helmholtz instability, exists for any, however weak, plasma flow velocities.
TL;DR: In this article, the model equations governing the excitation of weak whistler by a stronger Kinetic Alfven wave (KAW) in the plasma having β value (β ≫ me/mi), where beta is the ratio of the ion sound speed to the Alfven speed, were presented.
Abstract: This work presents the model equations governing the excitation of weak whistler by a stronger Kinetic Alfven wave (KAW) in the plasma having β value (β ≫ me/mi, where beta is the ratio of the ion sound speed to the Alfven speed), applicable to magnetotail in Earth's magnetosphere, when the ponderomotive nonlinearity is incorporated in the KAW dynamics. Numerical solution of the model equations has been obtained when the incident pump KAW is having a small perturbation. Energy exchange between main KAW and perturbation and the resulting localized structures of the KAW have been studied. A weak whistler signal propagating in these localized structures is amplified and leads to the development of envelope solitons. Our result reveals that the amplified (excited) whistler has an electric field power spectrum that is steeper than k−8/3. This result is consistent with recent observations by the Cluster spacecraft Eastwood et al. (Phys. Rev. Lett., vol. 102, 2009, 035001) in the magnetotail region of the Earth's magnetosphere.
TL;DR: In this paper, the generalized Lorentz tensor was proposed for ionized media and its expression for a fully ionized medium subject to an external electromagnetic field is discussed, as well as the plasma conservation equations.
Abstract: Following the arguments presented by Mansuripur [Opt. Express, vol. 16, 2008, pp. 14821–14835], we suggest a form for the macroscopic electromagnetic stress tensor appropriate for ionized media. The generalized Lorentz force includes the effects of polarization forces as well as those on the free charge and current densities. The resulting tensor is written in terms of the fields D, B, E, and H. Its expression for a fully ionized medium subject to an external electromagnetic field is discussed, as are the plasma conservation equations. An apparatus is suggested for its experimental discrimination.
TL;DR: In this paper, the behavior of the floating potential in an electronegative plasma sheath is studied, where negative ion temperature has been observed to strongly affect the variation of floating potential.
Abstract: Through a simple one-dimensional collisionless plasma sheath model, behavior of the floating potential in an electronegative plasma sheath is studied. Specially, the floating potential behavior as a function of the plasma electronegativity for various negative ion temperatures has been studied. It has been observed that negative ion temperature strongly affects the variation of floating potential.
TL;DR: In this article, an analytical study of the impact of image force on the kinetics of an irradiated complex plasma is presented, which includes both the number and energy balance of electrons/ions along with the charge neutrality condition.
Abstract: This paper presents an analytical study of the impact of image force on the kinetics of an irradiated complex plasma. The formulation is based on the average charge theory and includes both the number and energy balance of electrons/ions along with the charge neutrality condition. The dependence of reduction in the potential energy surface barrier (and work function) on the number density of dust particles has been investigated and its impact on the charging of dust grains and other physical plasma parameters has been discussed. An interesting conclusion is the fact that the image force consideration leads to larger magnitude of negative charge on the dust particles and the effective work function approaches the value for plane surface with increasing size and number density of dust grains.
TL;DR: In this article, the relativistic electron motions in a two-frequency wiggler magnetic field with self-generated fields were investigated, and the steady-state orbit from the equations of motion was found.
Abstract: We investigate the relativistic electron motions in a two-frequency wiggler magnetic field with self-generated fields. The equations of motion are derived from the Hamiltonian which include the self-generated field, and we find the steady-state orbit from the equations of motion. The stability of electron motion in a two-frequency wiggler is examined by the numerical simulation. We analyze the a dynamical systems using the fast Fourier transformation and the Poincare surface of section to find the critical value which have the periodical electron motion and to optimize the two-frequency wiggler.