The adiabatic approximation solutions of cylindrical and spherical dust ion-acoustic solitary waves
Institute of Scientific and Technical Information of China (English)
吕克璞; 豆福全; 孙建安; 段文山; 石玉仁
2005-01-01
By using the equivalent particle theory, the adiabatic approximation solutions of the Korteweg-de Vries type equation (including KdV equation, cylindrical KdV equation and spherical KdV equation) in dust ion-acoustic solitary waves were obtained. The method can be extended to other nonlinear evolution equations.
Paul, Ashesh; Das, K P
2016-01-01
The purpose of this paper is to extend the recent work of Paul & Bandyopadhyay [Astrophys. Space Sci. 361, 172(2016)] on the existence of different dust ion acoustic solitary structures in an unmagnetized collisionless dusty plasma consisting of negatively charged static dust grains, adiabatic warm ions, nonthermal electrons and isothermal positrons in a more generalized form by considering nonthermal positrons instead of isothermal positrons. The present system supports both positive and negative potential double layers, coexistence of solitary waves of both polarities and positive potential supersolitons. The qualitative and the quantitative changes in existence domains of different solitary structures which occur for the presence of nonthermal positrons have been presented in comparison with the results of Paul & Bandyopadhyay [Astrophys. Space Sci. 361, 172(2016)]. The formation of supersoliton structures and their limitations have been analyzed with the help of phase portraits of the dynamical sy...
PIC simulation of compressive and rarefactive dust ion-acoustic solitary waves
Li, Zhong-Zheng; Zhang, Heng; Hong, Xue-Ren; Gao, Dong-Ning; Zhang, Jie; Duan, Wen-Shan; Yang, Lei
2016-08-01
The nonlinear propagations of dust ion-acoustic solitary waves in a collisionless four-component unmagnetized dusty plasma system containing nonextensive electrons, inertial negative ions, Maxwellian positive ions, and negatively charged static dust grains have been investigated by the particle-in-cell method. By comparing the simulation results with those obtained from the traditional reductive perturbation method, it is observed that the rarefactive KdV solitons propagate stably at a low amplitude, and when the amplitude is increased, the prime wave form evolves and then gradually breaks into several small amplitude solitary waves near the tail of soliton structure. The compressive KdV solitons propagate unstably and oscillation arises near the tail of soliton structure. The finite amplitude rarefactive and compressive Gardner solitons seem to propagate stably.
Energy Technology Data Exchange (ETDEWEB)
Mayout, Saliha; Tribeche, Mouloud, E-mail: mouloudtribeche@yahoo.fr [Plasma Physics Group (PPG), Theoretical Physics Laboratory (TPL), Faculty of Sciences- Physics, University of Bab-Ezzouar, U.S.T.H.B, B.P. 32, El Alia, Algiers 16111 (Algeria); Sahu, Biswajit [Department of Mathematics, West Bengal State University, Barasat, Kolkata-700126 (India)
2015-12-15
A theoretical study on the nonlinear propagation of nonplanar (cylindrical and spherical) dust ion-acoustic solitary waves (DIASW) is carried out in a dusty plasma, whose constituents are inertial ions, superthermal electrons, and charge fluctuating stationary dust particles. Using the reductive perturbation theory, a modified Korteweg-de Vries equation is derived. It is shown that the propagation characteristics of the cylindrical and spherical DIA solitary waves significantly differ from those of their one-dimensional counterpart.
Saini, N. S.; Singh, Kuldeep
2016-10-01
A head-on collision between two dust ion acoustic solitary waves (DIASWs) travelling in the opposite direction in a weakly relativistic plasma composed of four distinct particle populations, namely, weakly relativistic ion fluid, superthermal electrons as well as positrons, and immobile dust, is investigated. By employing extended Poincaré-Lighthill-Kuo method, two Korteweg-de Vries (KdV) equations are derived. The analytical phase shift after a head-on collision of two dust ion acoustic (DIA) solitary waves is also obtained. The combined effects of relativistic factor (β), electron to positron temperature ratio (α), ion to electron temperature ratio (σ), positron to electron density ratio (P), dust density ratio (d), and superthermality of electrons as well as positrons (via κ) on the phase shifts are numerically studied. All these physical parameters have also changed the potential amplitude and the width of colliding solitary waves. It is found that the presence of superthermal electrons as well as positrons and dust grains has emphatic influence on the phase shifts and potential pulse profiles of compressive DIA solitons. Our results are general and may be helpful in understanding a head-on collision between two DIASWs in astrophysical and laboratory plasmas, especially the interaction of pulsar relativistic winds with supernova ejecta that produces the superthermal particles and relativistic ions.
Haider, M. M.; Rahman, O.
2016-12-01
An attempt has been made to study the multi-dimensional instability of dust-ion-acoustic (DIA) solitary waves (SWs) in magnetized multi-ion plasmas containing opposite polarity ions, opposite polarity dusts and non-thermal electrons. First of all, we have derived Zakharov-Kuznetsov (ZK) equation to study the DIA SWs in this case using reductive perturbation method as well as its solution. Small- k perturbation technique was employed to find out the instability criterion and growth rate of such a wave which can give a guideline in understanding the space and laboratory plasmas, situated in the D-region of the Earth's ionosphere, mesosphere, and solar photosphere, as well as the microelectronics plasma processing reactors.
Mamun, A A; Shukla, P K
2009-09-01
Effects of the nonthermal distribution of electrons as well as the polarity of the net dust-charge number density on nonplanar (viz. cylindrical and spherical) dust-ion-acoustic solitary waves (DIASWs) are investigated by employing the reductive perturbation method. It is found that the basic features of the DIASWs are significantly modified by the effects of nonthermal electron distribution, polarity of net dust-charge number density, and nonplanar geometry. The implications of our results in some space and laboratory dusty plasma environments are briefly discussed.
Eghbali, M.; Farokhi, B.; Eslamifar, M.
2017-01-01
The nonlinear propagation of cylindrical and spherical dust-ion-acoustic (DIA) envelope solitary waves in unmagnetized dusty plasma consisting of dust particles with opposite polarity and non-extensive distribution of electron is investigated. By using the reductive perturbation method, the modified nonlinear Schrödinger (NLS) equation in cylindrical and spherical geometry is obtained. The modulational instability (MI) of DIA waves governed by the NLS equation is also presented. The effects of different ranges of the non-extensive parameter q on the MI are studied. The growth rate of the MI is also given for different values of q. It is found that the basic features of the DIA waves are significantly modified by non-extensive electron distribution, polarity of the net dust-charge number density and non-planar geometry.
Indian Academy of Sciences (India)
M EGHBALI; B FAROKHI; M ESLAMIFAR
2017-01-01
The nonlinear propagation of cylindrical and spherical dust-ion-acoustic (DIA) envelope solitary waves in unmagnetized dusty plasma consisting of dust particles with opposite polarity and non-extensive distribution of electron is investigated. By using the reductive perturbation method, the modified nonlinear Schrödinger (NLS) equation in cylindrical and spherical geometry is obtained. The modulational instability (MI) of DIA waves governed by the NLS equation is also presented. The effects of different ranges of the non-extensive parameter $q$ on the MI are studied. The growth rate of the MI is also given for different values of $q$. It is found that the basic features of the DIA waves are significantly modified by non-extensive electron distribution, polarity of the netdust-charge number density and non-planar geometry.
Institute of Scientific and Technical Information of China (English)
T.Akhter; M.M.Hossain; A.A.Mamun
2013-01-01
Cylindrical and spherical (nonplanar) solitary waves (SWs) and double layers (DLs) in a multi-ion plasma system (containing inertial positively as well as negatively charged ions,non-inertial degenerate electrons,and negatively charged static dust) are studied by employing the standard reductive perturbation method.The modified Gardner (MG) equation describing the nonlinear propagation of the dust ion-acoustic (DIA) waves is derived,and its nonplanar SWs and DLs solutions are numerically analyzed.The parametric regimes for the existence of SWs,which are associated with both positive and negative potential,and DLs which are associated with negative potential,are obtained.The basic features of nonplanar DIA SWs,and DLs,which are found to be different from planar ones,are also identified.
Oblique propagation of dust ion-acoustic solitary waves in a magnetized dusty pair-ion plasma
Misra, A P
2013-01-01
We study the linear and nonlinear properties of electrostatic waves in a magnetized pair-ion plasma with immobile positively charged dusts. For the obliquely propagating linear waves, a general dispersion relation is derived, from which it is shown that the low-frequency (in comparison with the negative-ion cyclotron frequency) long-wavelength "slow" and a "fast" modes can propagate as dust ion-acoustic (DIA) and dust ion-cyclotron (DIC)-like waves. The properties of these modes are analyzed with the effects of obliqueness of propagation $(\\theta)$, the negative to positive ion mass ratio $(m)$, the ratio of negative to positive ion temperatures $(T)$, the static magnetic field as well as the presence of charged dusts (characterized by the dust to negative-ion number density $\\delta$) in the plasma. In the nonlinear regime, a standard reductive perturbation technique is used to derive a Korteweg-de Vries (KdV) equation for the oblique DIA waves. We show that the KdV equation can admit either compressive or ra...
Oblique propagation of dust ion-acoustic solitary waves in a magnetized dusty pair-ion plasma
Energy Technology Data Exchange (ETDEWEB)
Misra, A. P., E-mail: apmisra@visva-bharati.ac.in, E-mail: apmisra@gmail.com; Barman, Arnab [Department of Mathematics, Siksha Bhavana, Visva-Bharati University, Santiniketan-731 235, West Bengal (India)
2014-07-15
We investigate the propagation characteristics of electrostatic waves in a magnetized pair-ion plasma with immobile charged dusts. It is shown that obliquely propagating (OP) low-frequency (in comparison with the negative-ion cyclotron frequency) long-wavelength “slow” and “fast” modes can propagate, respectively, as dust ion-acoustic (DIA) and dust ion-cyclotron (DIC)-like waves. The properties of these modes are studied with the effects of obliqueness of propagation (θ), the static magnetic field, the ratios of the negative to positive ion masses (m), and temperatures (T) as well as the dust to negative-ion number density ratio (δ). Using the standard reductive perturbation technique, we derive a Korteweg-de Vries (KdV) equation which governs the evolution of small-amplitude OP DIA waves. It is found that the KdV equation admits only rarefactive solitons in plasmas with m well below its critical value m{sub c} (≫ 1) which typically depends on T and δ. It is shown that the nonlinear coefficient of the KdV equation vanishes at m = m{sub c}, i.e., for plasmas with much heavier negative ions, and the evolution of the DIA waves is then described by a modified KdV (mKdV) equation. The latter is shown to have only compressive soliton solution. The properties of both the KdV and mKdV solitons are studied with the system parameters as above, and possible applications of our results to laboratory and space plasmas are briefly discussed.
Quantum ion-acoustic solitary waves in weak relativistic plasma
Indian Academy of Sciences (India)
Biswajit Sahu
2011-06-01
Small amplitude quantum ion-acoustic solitary waves are studied in an unmagnetized twospecies relativistic quantum plasma system, comprised of electrons and ions. The one-dimensional quantum hydrodynamic model (QHD) is used to obtain a deformed Korteweg–de Vries (dKdV) equation by reductive perturbation method. A linear dispersion relation is also obtained taking into account the relativistic effect. The properties of quantum ion-acoustic solitary waves, obtained from the deformed KdV equation, are studied taking into account the quantum mechanical effects in the weak relativistic limit. It is found that relativistic effects signiﬁcantly modify the properties of quantum ion-acoustic waves. Also the effect of the quantum parameter on the nature of solitary wave solutions is studied in some detail.
Nonlinear dust-ion-acoustic waves in a multi-ion plasma with trapped electrons
Indian Academy of Sciences (India)
S S Duha; B Shikha; A A Mamun
2011-08-01
A dusty multi-ion plasma system consisting of non-isothermal (trapped) electrons, Maxwellian (isothermal) light positive ions, warm heavy negative ions and extremely massive charge ﬂuctuating stationary dust have been considered. The dust-ion-acoustic solitary and shock waves associated with negative ion dynamics, Maxwellian (isothermal) positive ions, trapped electrons and charge ﬂuctuating stationary dust have been investigated by employing the reductive perturbation method. The basic features of such dust-ion-acoustic solitary and shock waves have been identiﬁed. The implications of our ﬁndings in space and laboratory dusty multi-ion plasmas are discussed.
The Kadomtsev-Petviashvili equation for dust ion-acoustic solitons in pair-ion plasmas
Institute of Scientific and Technical Information of China (English)
Hafeez Ur-Rehman
2013-01-01
Using the reductive perturbation method,we have derived the Kadomtsev-Petviashvili (KP) equation to study the nonlinear properties of electrostatic collisionless dust ion-acoustic solitons in pair-ion (p-i) plasmas.We have chosen the fluid model for the positive ions,the negative ions,and a fraction of static charged (both positively and negatively) dust particles.Numerical solutions of these dust ion-acoustic solitons are plotted and their characteristics are discussed.It is found that only the amplitudes of the electrostatic dust ion-acoustic solitons vary when the dust is introduced in the pair-ion plasma.It is also noticed that the amplitude and the width of these solitons both vary when the thermal energy of the positive or negative ions is varied.It is shown that potential hump structures are formed when the temperature of the negative ions is higher than that of the positive ions,and potential dip structures are observed when the temperature of the positive ions supersedes that of the negative ions.As the pair-ion plasma mimics the electron-positron plasma,thus our results might be helpful in understanding the nonlinear dust ion acoustic solitary waves in super dense astronomical bodies.
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Samiran [College of Textile Technology, Berhampore 742101, Murshidabad, West Bengal (India)]. E-mail: sran_g@yahoo.com
2005-04-11
It has been found that the dust ion acoustic solitary wave (DIASW) is governed by a modified form of Korteweg-de Vries (KdV) equation modified by the effects of ionization, particle collisions and bounded nonplanar geometry. Approximate analytical time evolution solution and also the numerical solution of modified form of KdV equation reveal that the wave amplitude grows exponentially with time due to ionization, whereas the bounded nonplanar geometry and collision reduce the instability growth rate.
Hafez, M. G.; Talukder, M. R.
2015-09-01
This work investigates the theoretical and numerical studies on nonlinear propagation of ion acoustic solitary waves (IASWs) in an unmagnetized plasma consisting of nonextensive electrons, Boltzmann positrons and relativistic thermal ions. The Korteweg-de Vries (KdV) equation is derived by using the well known reductive perturbation method. This equation admits the soliton like solitary wave solution. The effects of phase velocity, amplitude of soliton, width of soliton and electrostatic nonlinear propagation of weakly relativistic ion-acoustic solitary waves have been discussed with graphical representation found in the variation of the plasma parameters. The obtained results can be helpful in understanding the features of small but finite amplitude localized relativistic ion-acoustic waves for an unmagnetized three component plasma system in astrophysical compact objects.
Directory of Open Access Journals (Sweden)
S. S. Ghosh
2004-01-01
Full Text Available The presence of dynamic, large amplitude solitary waves in the auroral regions of space is well known. Since their velocities are of the order of the ion acoustic speed, they may well be considered as being generated from the nonlinear evolution of ion acoustic waves. However, they do not show the expected width-amplitude correlation for K-dV solitons. Recent POLAR observations have actually revealed that the low altitude rarefactive ion acoustic solitary waves are associated with an increase in the width with increasing amplitude. This indicates that a weakly nonlinear theory is not appropriate to describe the solitary structures in the auroral regions. In the present work, a fully nonlinear analysis based on Sagdeev pseudopotential technique has been adopted for both parallel and oblique propagation of rarefactive solitary waves in a two electron temperature multi-ion plasma. The large amplitude solutions have consistently shown an increase in the width with increasing amplitude. The width-amplitude variation profile of obliquely propagating rarefactive solitary waves in a magnetized plasma have been compared with the recent POLAR observations. The width-amplitude variation pattern is found to fit well with the analytical results. It indicates that a fully nonlinear theory of ion acoustic solitary waves may well explain the observed anomalous width variations of large amplitude structures in the auroral region.
Quasi-periodic behavior of ion acoustic solitary waves in electron-ion quantum plasma
Energy Technology Data Exchange (ETDEWEB)
Sahu, Biswajit [Department of Mathematics, West Bengal State University Barasat, Kolkata-700126 (India); Poria, Swarup [Department of Applied Mathematics, University of Calcutta Kolkata-700009 (India); Narayan Ghosh, Uday [Department of Mathematics, Siksha Bhavana, Visva Bharati University Santiniketan (India); Roychoudhury, Rajkumar [Physics and Applied Mathematics Unit, Indian Statistical Institute Kolkata-700108 (India)
2012-05-15
The ion acoustic solitary waves are investigated in an unmagnetized electron-ion quantum plasmas. The one dimensional quantum hydrodynamic model is used to study small as well as arbitrary amplitude ion acoustic waves in quantum plasmas. It is shown that ion temperature plays a critical role in the dynamics of quantum electron ion plasma, especially for arbitrary amplitude nonlinear waves. In the small amplitude region Korteweg-de Vries equation describes the solitonic nature of the waves. However, for arbitrary amplitude waves, in the fully nonlinear regime, the system exhibits possible existence of quasi-periodic behavior for small values of ion temperature.
Parveen, Shahida; Mahmood, Shahzad; Adnan, Muhammad; Qamar, Anisa
2016-09-01
The head on collision between two dust ion acoustic (DIA) solitary waves, propagating in opposite directions, is studied in an unmagnetized plasma constituting adiabatic ions, static dust charged (positively/negatively) grains, and non-inertial kappa distributed electrons. In the linear limit, the dispersion relation of the dust ion acoustic (DIA) solitary wave is obtained using the Fourier analysis. For studying characteristic head-on collision of DIA solitons, the extended Poincaré-Lighthill-Kuo method is employed to obtain Korteweg-de Vries (KdV) equations with quadratic nonlinearities and investigated the phase shifts in their trajectories after the interaction. It is revealed that only compressive solitary waves can exist for the positive dust charged concentrations while for negative dust charge concentrations both the compressive and rarefactive solitons can propagate in such dusty plasma. It is found that for specific sets of plasma parameters, the coefficient of nonlinearity disappears in the KdV equation for the negative dust charged grains. Therefore, the modified Korteweg-de Vries (mKdV) equations with cubic nonlinearity coefficient, and their corresponding phase shift and trajectories, are also derived for negative dust charged grains plasma at critical composition. The effects of different plasma parameters such as superthermality, concentration of positively/negatively static dust charged grains, and ion to electron temperature ratio on the colliding soliton profiles and their corresponding phase shifts are parametrically examined.
Hafez, M. G.; Talukder, M. R.; Sakthivel, R.
2016-05-01
The theoretical and numerical studies have been investigated on nonlinear propagation of weakly relativistic ion acoustic solitary waves in an unmagnetized plasma system consisting of nonextensive electrons, positrons and relativistic thermal ions. To study the characteristics of nonlinear propagation of the three-component plasma system, the reductive perturbation technique has been applied to derive the Korteweg-de Vries equation, which divulges the soliton-like solitary wave solution. The ansatz method is employed to carry out the integration of this equation. The effects of nonextensive electrons, positrons and relativistic thermal ions on phase velocity, amplitude and width of soliton and electrostatic nonlinear propagation of weakly relativistic ion acoustic solitary waves have been discussed taking different plasma parameters into consideration. The obtained results can be useful in understanding the features of small amplitude localized relativistic ion acoustic solitary waves in an unmagnetized three-component plasma system for hard thermal photon production with relativistic heavy ions collision in quark-gluon plasma as well as for astrophysical plasmas.
Compressive and rarefactive dust-ion-acoustic Gardner solitons in a multi-component dusty plasma
Energy Technology Data Exchange (ETDEWEB)
Ema, S. A.; Ferdousi, M.; Mamun, A. A. [Department of Physics, Jahangirnagar University, Savar, Dhaka-1342 (Bangladesh)
2015-04-15
The linear and nonlinear propagations of dust-ion-acoustic solitary waves (DIASWs) in a collisionless four-component unmagnetized dusty plasma system containing nonextensive electrons, inertial negative ions, Maxwellian positive ions, and negatively charged static dust grains have been investigated theoretically. The linear properties are analyzed by using the normal mode analysis and the reductive perturbation method is used to derive the nonlinear equations, namely, the Korteweg-de Vries (K-dV), the modified K-dV (mK-dV), and the Gardner equations. The basic features (viz., polarity, amplitude, width, etc.) of Gardner solitons (GS) are found to exist beyond the K-dV limit and these dust-ion-acoustic GS are qualitatively different from the K-dV and mK-dV solitons. It is observed that the basic features of DIASWs are affected by various plasma parameters (viz., electron nonextensivity, negative-to-positive ion number density ratio, electron-to-positive ion number density ratio, electron-to-positive ion temperature ratio, etc.) of the considered plasma system. The findings of our results obtained from this theoretical investigation may be useful in understanding the nonlinear structures and the characteristics of DIASWs propagating in both space and laboratory plasmas.
Weakly dissipative dust-ion acoustic wave modulation
Alinejad, H.; Mahdavi, M.; Shahmansouri, M.
2016-02-01
The modulational instability of dust-ion acoustic (DIA) waves in an unmagnetized dusty plasma is investigated in the presence of weak dissipations arising due to the low rates (compared to the ion oscillation frequency) of ionization recombination and ion loss. Based on the multiple space and time scales perturbation, a new modified nonlinear Schrödinger equation governing the evolution of modulated DIA waves is derived with a linear damping term. It is shown that the combined action of all dissipative mechanisms due to collisions between particles reveals the permitted maximum time for the occurrence of the modulational instability. The influence on the modulational instability regions of relevant physical parameters such as ion temperature, dust concentration, ionization, recombination and ion loss is numerically examined. It is also found that the recombination frequency controls the instability growth rate, whereas recombination and ion loss make the instability regions wider.
Two-dimensional cylindrical ion-acoustic solitary and rogue waves in ultrarelativistic plasmas
Energy Technology Data Exchange (ETDEWEB)
Ata-ur-Rahman [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Centre for Physics at QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Ali, S. [National Centre for Physics at QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt); Mushtaq, A. [National Centre for Physics at QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Department of Physics, Abdul Wali Khan University, Mardan 23200 (Pakistan)
2013-07-15
The propagation of ion-acoustic (IA) solitary and rogue waves is investigated in a two-dimensional ultrarelativistic degenerate warm dense plasma. By using the reductive perturbation technique, the cylindrical Kadomtsev–Petviashvili (KP) equation is derived, which can be further transformed into a Korteweg–de Vries (KdV) equation. The latter admits a solitary wave solution. However, when the frequency of the carrier wave is much smaller than the ion plasma frequency, the KdV equation can be transferred to a nonlinear Schrödinger equation to study the nonlinear evolution of modulationally unstable modified IA wavepackets. The propagation characteristics of the IA solitary and rogue waves are strongly influenced by the variation of different plasma parameters in an ultrarelativistic degenerate dense plasma. The present results might be helpful to understand the nonlinear electrostatic excitations in astrophysical degenerate dense plasmas.
Propagation of ion-acoustic solitary waves in a relativistic electron-positron-ion plasma
Saberian, E; Akbari-Moghanjoughi, M
2011-01-01
Propagation of large amplitude ion-acoustic solitary waves (IASWs) in a fully relativistic plasma consisting of cold ions and ultrarelativistic hot electrons and positrons is investigated using the Sagdeev's pseudopotential method in a relativistic hydrodynamics model. Effects of streaming speed of plasma fluid, thermal energy, positron density and positron temperature on large amplitude IASWs are studied by analysis of the pseudopotential structure. It is found that in regions that the streaming speed of plasma fluid is larger than that of solitary wave, by increasing the streaming speed of plasma fluid the depth and width of potential well increases and resulting in narrower solitons with larger amplitude. This behavior is opposite for the case where the streaming speed of plasma fluid is smaller than that of solitary wave. On the other hand, increase of the thermal energy results in wider solitons with smaller amplitude, because the depth and width of potential well decreases in that case. Additionally, th...
Paul, Ashesh
2016-01-01
Employing the Sagdeev pseudo-potential technique the ion acoustic solitary structures have been investigated in an unmagnetized collisionless plasma consisting of adiabatic warm ions, nonthermal electrons and isothermal positrons. The qualitatively different compositional parameter spaces clearly indicate the existence domains of solitons and double layers with respect to any parameter of the present plasma system. The present system supports the negative potential double layer which always restricts the occurrence of negative potential solitons. The system also supports positive potential double layers when the ratio of the average thermal velocity of positrons to that of electrons is less than a critical value. However, there exists a parameter regime for which the positive potential double layer is unable to restrict the occurrence of positive potential solitary waves and in this region of the parameter space, there exist positive potential solitary waves after the formation of a positive potential double ...
Saha, Asit; Chatterjee, Prasanta; Chatterjee
2014-08-01
Ion acoustic solitary waves and periodic waves in an unmagnetized plasma with superthermal (kappa-distributed) electrons and positrons are investigated through a non-perturbative approach. Model equations are transformed to a planar dynamical system. Then by using the bifurcations of phase portraits of this planar dynamical system, we have established that our model has solitary wave and periodic wave solutions. We have obtained two analytical solutions for these solitary and periodic waves depending on the parameters. From these solitary wave and periodic wave solutions, we have shown the combined effects of temperature ratio (σ) of electrons and positrons, spectral index (κ), speed of the traveling wave (v), and density ratio (p) of positrons and electrons on the characteristics of ion acoustic solitary and periodic waves. The spectral index, density ratio, speed of the traveling wave, and temperature ratio significantly affect the characteristics of ion acoustic solitary and periodic structures. The present study might be helpful to understand the salient features of nonlinear ion acoustic solitary and periodic structures in the interstellar medium.
Applications of a simplified bilinear method to ion-acoustic solitary waves in plasma
Awawdeh, Fadi; Jaradat, H. M.; Al-Shara', S.
2012-02-01
In this paper, we propose a computational method for nonlinear partial differential equations modeling ion-acoustic waves as well as dusty plasmas in laboratory and space sciences. Many types of solitary waves including soliton solutions, N-soliton solutions and singular N-soliton solutions are derived. The characteristic line method and graphical analysis are applied to discuss the solitonic propagation and collision, including the bidirectional solitons and elastic interactions. Furthermore, the effects of inhomogeneities of media and nonuniformities of boundaries, depicted by the variable coefficients, on the soliton behavior are discussed.
Filamentation instability of current-driven dust ion-acoustic waves in a collisional dusty plasma
Energy Technology Data Exchange (ETDEWEB)
Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 19839-63113 (Iran, Islamic Republic of); Haghtalab, T.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand 97179-63384 (Iran, Islamic Republic of)
2011-11-15
A theoretical investigation has been made of the dust ion-acoustic filamentation instability in an unmagnetized current-driven dusty plasma by using the Lorentz transformation formulas. The effect of collision between the charged particles with neutrals and their thermal motion on this instability is considered. Developing the filamentation instability of the current-driven dust ion-acoustic wave allows us to determine the period and the establishment time of the filamentation structure and threshold for instability development.
Heavy-ion-acoustic solitary and shock waves in an adiabatic multi-ion plasma
Energy Technology Data Exchange (ETDEWEB)
Hossen, M.A.; Rahman, M.M.; Mamun, A.A., E-mail: armanplasma@gmail.com [Department of Physics, Jahangirnagar University, Savar, Dhaka (Bangladesh); Hossen, M.R. [Department of Natural Sciences, Daffodil International University, Dhanmondi, Dhaka (Bangladesh)
2015-08-15
The standard reductive perturbation method has been employed to derive the Korteweg-deVries (K-dV) and Burgers (BG) equations to investigate the basic properties of heavy-ion-acoustic (HIA) waves in a plasma system which is supposed to be composed of nonthermal electrons, Boltzmann distributed light ions, and adiabatic positively charged inertial heavy ions. The HIA solitary and shock structures are found to exist with either positive or negative potential. It is found that the effects of adiabaticity of inertial heavy ions, nonthermality of electrons, and number densities of plasma components significantly modify the basic properties of the HIA solitary and shock waves. The implications of our results may be helpful in understanding the electrostatic perturbations in various laboratory and astrophysical plasma environments. (author)
The effect of q-distributed electrons on the head-on collision of ion acoustic solitary waves
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Uday Narayan; Chatterjee, Prasanta [Department of Mathematics, Siksha Bhavana Visva Bharati University, Santiniketan 731235 (India); Roychoudhury, Rajkumar [Physics and Applied Mathematics, ISI, Kolkata 700009 (India)
2012-01-15
The head-on collision of ion acoustic solitary waves (IASWs) in two component plasma comprising nonextensive distributed electrons is investigated. Two opposite directional Kortewg-de-vries (KdV) equations are derived and the phase shift due to collision is obtained using the extended version of Poincare-Lighthill-Kuo method. Different ranges of nonextensive parameter q are considered and their effects on phase shifts are observed. It is found that the presence of nonextensive distributed electrons plays a significant role on the nature of collision of ion acoustic solitary waves.
Hafez, M. G.; Roy, N. C.; Talukder, M. R.; Hossain Ali, M.
2016-08-01
The characteristics of the nonlinear oblique propagation of ion acoustic solitary waves in unmagnetized plasmas consisting of Boltzmann positrons, trapped electrons and ions are investigated. The modified Kadomtsev-Petviashivili ( m K P ) equation is derived employing the reductive perturbation technique. The parametric effects on phase velocity, Sagdeev potential, amplitude and width of solitons, and electrostatic ion acoustic solitary structures are graphically presented with the relevant physical explanations. This study may be useful for the better understanding of physical phenomena concerned in plasmas in which the effects of trapped electrons control the dynamics of wave.
Oblique propagation of ion-acoustic solitary waves in a magnetized electron-positron-ion plasma
Energy Technology Data Exchange (ETDEWEB)
Ferdousi, M.; Sultana, S.; Mamun, A. A. [Department of Physics, Jahangirnagar University, Savar, Dhaka-1342 (Bangladesh)
2015-03-15
The properties of obliquely propagating ion-acoustic solitary waves in the presence of ambient magnetic field have been investigated theoretically in an electron-positron-ion nonthermal plasma. The plasma nonthermality is introduced via the q-nonextensive distribution of electrons and positrons. The Korteweg-de Vries (K-dV) and modified K-dV (mK-dV) equations are derived by adopting reductive perturbation method. The solution of K-dV and modified K-dV equation, which describes the solitary wave characteristics in the long wavelength limit, is obtained by steady state approach. It is seen that the electron and positron nonextensivity and external magnetic field (obliqueness) have significant effects on the characteristics of solitary waves. A critical value of nonextensivity is found for which solitary structures transit from positive to negative potential. The findings of this investigation may be used in understanding the wave propagation in laboratory and space plasmas where static external magnetic field is present.
Ghebache, Siham; Tribeche, Mouloud
2017-10-01
The problem of arbitrary amplitude ion-acoustic solitary waves (IASWs), which accompany electronegative plasmas having positive ions, negative ions, and nonextensive electrons is addressed. The energy integral equation with a new Sagdeev potential is analyzed to examine the existence regions of the IASWs. Different types of electronegative plasmas inspired from the experimental studies of Ichiki et al. (2001) are discussed. Our results show that in such plasmas IASWs, the amplitude and nature of which depend sensitively on the mass and density ratio of the positive and negative ions as well as the q-nonextensive parameter, can exist. Interestingly, one finds that our plasma model supports the coexistence of smooth rarefactive and spiky compressive IASWs. Our results complement and provide new insights on previously published findings on this problem.
Role of nonthermal electrons on dust ion acoustic double layer with variable dust charge
Borah, Prathana; Gogoi, Deepshikha; Das, Nilakshi
2016-01-01
The presence of nonthermal electron may play an important role in the formation of nonlinear structures in plasma. On the other hand, fluctuation of dust charge is an important and unique feature of complex plasma and it gives rise to a dissipative effect in the system leading to the formation of nonlinear structures due to the balance between nonlinearity and dissipation. In this paper, the propagation of nonlinear dust ion acoustic (DIA) wave in unmagnetized collisionless dusty plasma consisting of ions, nonthermal electrons and dust grains with variable negative charge has been investigated using the Sagdeev potential method. The existence domain of rarefactive double layer (DL) in the DIA wave has been investigated for the range of plasma parameters. The real potential has been obtained by numerically solving the Poisson equation and dust charging equation. It is observed that the presence of nonthermal electrons strengthens the DIA DL.
Dust-ion acoustic cnoidal waves and associated nonlinear ion flux in a nonthermal dusty plasma
Ur-Rehman, Hafeez; Mahmood, S.
2016-09-01
The dust-ion acoustic nonlinear periodic (cnoidal) waves and solitons are investigated in a dusty plasma containing dynamic cold ions, superthermal kappa distributed electrons and static charged dust particles. The massive dust particles can have positive or negative charge depending on the plasma environment. Using reductive perturbation method (RPM) with appropriate periodic boundary conditions, the evolution equations for the first and second order nonlinear potentials are derived. The first order potential is determined through Korteweg-de Vries (KdV) equation which gives dust-ion acoustic cnoidal waves and solitons structures. The solution of second order nonlinear potential is obtained through an inhomogeneous differential equation derived from collecting higher order terms of dynamic equations, which is linear for second order electrostatic potential. The nonlinear ion flux associated with the cnoidal waves is also found out numerically. The numerical plots of the dust-ion acoustic cnoidal wave and soliton structures for both positively and negatively charged dust particles cases and nonthermal electrons are also presented for illustration. It is found that only compressive nonlinear electrostatic structures are formed in case of positively dust charged particles while both compressive and rarefactive nonlinear structures are obtained in case of negatively charged particles depending on the negatively charged dust density in a nonthermal dusty plasma. The numerical results are obtained using data of the ionospheric region containing dusty plasma exist in the literature.
Shah, M. G.; Rahman, M. M.; Hossen, M. R.; Mamun, A. A.
2016-02-01
A theoretical investigation on heavy ion-acoustic (HIA) solitary and shock structures has been accomplished in an unmagnetized multispecies plasma consisting of inertialess kappa-distributed superthermal electrons, Boltzmann light ions, and adiabatic positively charged inertial heavy ions. Using the reductive perturbation technique, the nonplanar (cylindrical and spherical) Kortewg-de Vries (KdV) and Burgers equations have been derived. The solitary and shock wave solutions of the KdV and Burgers equations, respectively, have been numerically analyzed. The effects of superthermality of electrons, adiabaticity of heavy ions, and nonplanar geometry, which noticeably modify the basic features (viz. polarity, amplitude, phase speed, etc.) of small but finite amplitude HIA solitary and shock structures, have been carefully investigated. The HIA solitary and shock structures in nonplanar geometry have been found to distinctly differ from those in planar geometry. Novel features of our present attempt may contribute to the physics of nonlinear electrostatic perturbation in astrophysical and laboratory plasmas.
Modified ion-acoustic solitary waves in plasmas with field-aligned shear flows
Energy Technology Data Exchange (ETDEWEB)
Saleem, H. [Department of Space Science, Institute of Space Technology, 1-Islamabad Highway, Islamabad (Pakistan); Theoretical Research Institute, Pakistan Academy of Sciences, 3-Constitution Avenue G-5/3, Islamabad (Pakistan); Ali, S. [Theoretical Research Institute, Pakistan Academy of Sciences, 3-Constitution Avenue G-5/3, Islamabad (Pakistan); National Centre for Physics (NCP) at Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Haque, Q. [Theoretical Research Institute, Pakistan Academy of Sciences, 3-Constitution Avenue G-5/3, Islamabad (Pakistan); National Centre for Physics (NCP) at Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)
2015-08-15
The nonlinear dynamics of ion-acoustic waves is investigated in a plasma having field-aligned shear flow. A Korteweg-deVries-type nonlinear equation for a modified ion-acoustic wave is obtained which admits a single pulse soliton solution. The theoretical result has been applied to solar wind plasma at 1 AU for illustration.
Energy Technology Data Exchange (ETDEWEB)
Singh, S. V.; Devanandhan, S.; Lakhina, G. S. [Indian Institute of Geomagnetism, Navi Mumbai (India); Bharuthram, R. [University of the Western Cape, Bellville (South Africa)
2013-01-15
Obliquely propagating ion-acoustic soliatry waves are examined in a magnetized plasma composed of kappa distributed electrons and fluid ions with finite temperature. The Sagdeev potential approach is used to study the properties of finite amplitude solitary waves. Using a quasi-neutrality condition, it is possible to reduce the set of equations to a single equation (energy integral equation), which describes the evolution of ion-acoustic solitary waves in magnetized plasmas. The temperature of warm ions affects the speed, amplitude, width, and pulse duration of solitons. Both the critical and the upper Mach numbers are increased by an increase in the ion temperature. The ion-acoustic soliton amplitude increases with the increase in superthermality of electrons. For auroral plasma parameters, the model predicts the soliton speed, amplitude, width, and pulse duration, respectively, to be in the range of (28.7-31.8) km/s, (0.18-20.1) mV/m; (590-167) m, and (20.5-5.25) ms, which are in good agreement with Viking observations.
Dust ion-acoustic shock waves due to dust charge fluctuation in a superthermal dusty plasma
Energy Technology Data Exchange (ETDEWEB)
Alinejad, H., E-mail: alinejad@nit.ac.ir [Department of Physics, Faculty of Basic Science, Babol University of Technology, Babol 47148-71167 (Iran, Islamic Republic of); Research Institute for Fundamental Sciences (RIFS), University of Tabriz, 51664, Tabriz (Iran, Islamic Republic of); Tribeche, M. [Plasma Physics Group, Faculty of Sciences – Physics, University of Bab-Ezzouar (Algeria); Mohammadi, M.A. [Research Institute for Fundamental Sciences (RIFS), University of Tabriz, 51664, Tabriz (Iran, Islamic Republic of); Department of Atomic and Molecular Physics, Faculty of Physics, University of Tabriz, Tabriz (Iran, Islamic Republic of)
2011-11-14
The nonlinear propagation of dust ion-acoustic (DIA) shock waves is studied in a charge varying dusty plasma with electrons having kappa velocity distribution. We use hot ions with equilibrium streaming speed and a fast superthermal electron charging current derived from orbit limited motion (OLM) theory. It is found that the presence of superthermal electrons does not only significantly modify the basic properties of shock waves, but also causes the existence of shock profile with only positive potential in such plasma with parameter ranges corresponding to Saturn's rings. It is also shown that the strength and steepness of the shock waves decrease with increase of the size of dust grains and ion temperature. -- Highlights: ► The presence of superthermal electrons causes the existence of shock waves with only positive potential. ► The strength and steepness of the shock waves decrease with increase of the size of dust grains and ion temperature. ► As the electrons evolve toward their thermodynamic equilibrium, the shock structures are found with smaller amplitude.
Kourakis, I.; Elkamash, I. S.
2016-10-01
In a recent article (J. Plasma Phys., vol. 82, 2009, 905820104), weakly dissipative dust-ion acoustic wave modulation in dusty plasmas was considered. It is shown in this Comment that the analysis therein involved severe fallacies, and is in fact based on an erroneous plasma fluid model, which fails to satisfy an equilibrium condition, among other shortcomings. The subsequent analysis therefore is dubious and of limited scientific value.
Modulational Instability of Dust Ion Acoustic Waves in a Collisional Dusty Plasma
Institute of Scientific and Technical Information of China (English)
XUEJu-Kui
2003-01-01
The modulational instability of dust ion accoustic waves in a dust plasma with ion-dust collision effects is studied.Using the perturbation method,a modified nonlinear Schroedinger equation contains a damping term that comes from the effect of the ion-dust collision is derived.It is found that the inclusion of the ion-dust collision would modify the modulational instability of the wave packet and could not admit any stationary envelope solitary waves.
Effects of ion-fluid temperature on dust-ion-acoustic solitons
Indian Academy of Sciences (India)
Fatema Sayed; A A Mamun
2008-03-01
The properties of dust-ion-acoustic (DIA) solitons in an unmagnetized dusty plasma, whose constituents are adiabatic ion-fluid, Boltzmann electrons, and static dust particles, are investigated by employing the reductive perturbation method. The Korteweg-de Vries equation is derived and its stationary solution is numerically analyzed. The parametric regimes for the existence of positive and negative solitons are found. It has been shown that ion-fluid temperature not only significantly modifies the basic features (width and amplitude) of DIA solitons, but also introduces some new features of DIA solitons.
Solar wind implication on dust ion acoustic rogue waves
Energy Technology Data Exchange (ETDEWEB)
Abdelghany, A. M., E-mail: asmaaallah20@yahoo.com; Abd El-Razek, H. N., E-mail: hosam.abdelrazek@yahoo.com; El-Labany, S. K., E-mail: skellabany@hotmail.com [Theoretical Physics Group, Department of Physics, Faculty of Science, Damietta University, New Damietta 34517 (Egypt); Moslem, W. M., E-mail: wmmoslem@hotmail.com [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt); Centre for Theoretical Physics, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt)
2016-06-15
The relevance of the solar wind with the magnetosphere of Jupiter that contains positively charged dust grains is investigated. The perturbation/excitation caused by streaming ions and electron beams from the solar wind could form different nonlinear structures such as rogue waves, depending on the dominant role of the plasma parameters. Using the reductive perturbation method, the basic set of fluid equations is reduced to modified Korteweg-de Vries (KdV) and further modified (KdV) equation. Assuming that the frequency of the carrier wave is much smaller than the ion plasma frequency, these equations are transformed into nonlinear Schrödinger equations with appropriate coefficients. Rational solution of the nonlinear Schrödinger equation shows that rogue wave envelopes are supported by the present plasma model. It is found that the existence region of rogue waves depends on the dust-acoustic speed and the streaming temperatures for both the ions and electrons. The dependence of the maximum rogue wave envelope amplitude on the system parameters has been investigated.
Solar wind implication on dust ion acoustic rogue waves
Abdelghany, A. M.; Abd El-Razek, H. N.; Moslem, W. M.; El-Labany, S. K.
2016-06-01
The relevance of the solar wind with the magnetosphere of Jupiter that contains positively charged dust grains is investigated. The perturbation/excitation caused by streaming ions and electron beams from the solar wind could form different nonlinear structures such as rogue waves, depending on the dominant role of the plasma parameters. Using the reductive perturbation method, the basic set of fluid equations is reduced to modified Korteweg-de Vries (KdV) and further modified (KdV) equation. Assuming that the frequency of the carrier wave is much smaller than the ion plasma frequency, these equations are transformed into nonlinear Schrödinger equations with appropriate coefficients. Rational solution of the nonlinear Schrödinger equation shows that rogue wave envelopes are supported by the present plasma model. It is found that the existence region of rogue waves depends on the dust-acoustic speed and the streaming temperatures for both the ions and electrons. The dependence of the maximum rogue wave envelope amplitude on the system parameters has been investigated.
Study of trapping effect on ion-acoustic solitary waves based on a fully kinetic simulation approach
Jenab, S M
2016-01-01
A fully kinetic simulation approach, treating each plasma component based on the Vlasov equation, is adopted to study the disintegration of an initial density perturbation (IDP) into a number of ion-acoustic solitary waves (IASWs) in the presence of the trapping effect of electrons. The non-linear fluid theory developed by Schamel has identified three separate regimes of ion-acoustic solitary waves based on the trapping parameter. Here, the disintegration process and the resulting self-consistent IASWs are studied in a wide range of trapping parameters covering all the three regimes continuously. The dependency of features such as the time of disintegration, the number, speed and size of IASWs on the trapping parameter are focused upon. It is shown that an increase in this parameter slows down the propagation of IASWs while decreases their sizes in the phase space. These features of IASWs tend to saturate for large value of trapping parameters. The disintegration time shows a more complicated behavior than wh...
Hafez, M. G.; Talukder, M. R.; Hossain Ali, M.
2016-01-01
The Korteweg-de Vries Burgers (KdVB) -like equation is derived to study the characteristics of nonlinear propagation of ion acoustic solitions in a highly relativistic plasma containing relativistic ions and nonextensive distribution of electrons and positrons using the well known reductive perturbation technique. The KdVB-like equation is solved employing the Bernoulli's equation method taking unperturbed positron to electron concentration ratio, electron to positron temperature ratio, strength of nonextensivity, ion kinematic viscosity, and highly relativistic streaming factor. It is found that these parameters significantly modify the structures of the solitonic excitation. The ion acoustic shock profiles are observed due to the influence of ion kinematic viscosity. In the absence of dissipative term to the KdVB equation, compressive and rarefactive solitons are observed in case of superthermality, but only compressive solitons are found for the case of subthermality.
Guo, Shimin; Mei, Liquan; He, Ya-Ling; Ma, Chenchen; Sun, Youfa
2016-10-01
The nonlinear behavior of an ion-acoustic wave packet is investigated in a three-component plasma consisting of warm ions, nonthermal electrons and positrons. The nonthermal components are assumed to be inertialess and hot where they are modeled by the kappa distribution. The relevant processes, including the kinematic viscosity amongst the plasma constituents and the collision between ions and neutrals, are taken into consideration. It is shown that the dynamics of the modulated ion-acoustic wave is governed by the generalized complex Ginzburg-Landau equation with a linear dissipative term. The dispersion relation and modulation instability criterion for the generalized complex Ginzburg-Landau equation are investigated numerically. In the general dissipation regime, the effect of the plasma parameters on the dissipative solitary (dissipative soliton) and shock waves is also discussed in detail. The project is supported by NSF of China (11501441, 11371289, 11371288), National Natural Science Foundation of China (U1261112), China Postdoctoral Science Foundation (2014M560756), and Fundamental Research Funds for the Central Universities (xjj2015067).
Dokgo, Kyunghwan; Woo, Minho; Choi, Cheong-Rim; Min, Kyoung-Wook; Hwang, Junga
2016-09-01
Generation of coherent ion acoustic solitary waves (IASWs) in inhomogeneous plasmas by an odd eigenmode (OEM) of electron holes (EHs) is investigated using 1D electrostatic particle-in-cell (PIC) simulations. The OEM oscillates at a frequency comparable to the trapped electron bouncing frequency, as also demonstrated by Lewis' theoretical formalism about the linear eigenmode in Bernstein-Greene-Kruskal (BGK) equilibrium. The density gradient in the inhomogeneous plasmas causes asymmetry in the EH potential structure associated with the OEM, whose amplitude grows rapidly as it propagates through the density gradient region. As the ions interact with this asymmetric potential, which oscillates slowly enough for the ions to respond, they are ejected to the lower density side with a larger potential amplitude, forming a chain of IASWs coherently with the oscillation of the OEM.
Dust-ion-acoustic Gardner double layers in a dusty plasma with two-temperature electrons
Indian Academy of Sciences (India)
M M Masud; I Tasnim; A A Mamun
2015-01-01
The properties of dust-ion-acoustic Gardner double layers (DIA GDLs) in an unmagnetized dusty plasma, whose constituents are negatively-charged stationary dust, inertial ions, and Boltzmann electrons of two distinct temperatures, are rigorously investigated by employing the reductive perturbation method: Gardner approach. The standard Gardner equation is derived, and its double layer (DL) solution is obtained. It has been shown that the properties of the DIA GDLs are significantly modified by some plasma parameters (viz. = e1/e2, e1 = e10/i0, and e2 = e20/i0, where e1 (e2) is the cold (hot) electron temperature, e10 (e20) is the cold (hot) electron number density at equilibrium, and i0 is the ion number density at equilibrium). The implications of our investigation in understanding the basic features of nonlinear electrostatic perturbations observed in many space plasma systems and laboratory devices are briefly discussed.
Institute of Scientific and Technical Information of China (English)
华建军; 刘金远; 马腾才
2002-01-01
The effect of the charge fluctuation of dust particles on ion acoustic wave (IAW) excited through ionization instability was investigated. The hydrodynamic equations and linear time-dependent perturbation theory served as the starting point of theory, by which the dispersion relation and growth rate of the IAW were given. By comparing the results with the case of constant dust charges, it was found that the charge fluctuation of dust particles reduces the instability of the wave mode.
Kanti Das, Tushar; Ali, Rustam; Chatterjee, Prasanta
2017-10-01
The dynamics of dust ion acoustic waves (DIAWs) is investigated in a magnetized dusty plasma whose constituents are cold ions, superthermal electrons, and dust particles in the framework of a damped Zakharov-Kuznetsov (dZK) equation in the presence of externally applied periodic force. The dZK equation is derived employing the standard reductive perturbation technique. The effect of dust ion collision on the quasiperiodic and chaotic motion of dust ion acoustic waves is discussed. It is observed that the collision frequency νid 0 plays the role of a switching parameter from the quasiperiodic route to chaos for the DIAWs.
Energy Technology Data Exchange (ETDEWEB)
Guo, Shimin, E-mail: gsm861@126.com [School of Mathematics and Statistics, Xi’an Jiaotong University, Xi’an, 710049 (China); Research Group MAC, Centrum Wiskunde and Informatica, Amsterdam, 1098XG (Netherlands); Mei, Liquan, E-mail: lqmei@mail.xjtu.edu.cn [School of Mathematics and Statistics, Xi’an Jiaotong University, Xi’an, 710049 (China); Center for Computational Geosciences, Xi’an Jiaotong University, Xi’an, 710049 (China); Sun, Anbang [Research Group MAC, Centrum Wiskunde and Informatica, Amsterdam, 1098XG (Netherlands)
2013-05-15
The nonlinear propagation of planar and nonplanar (cylindrical and spherical) ion-acoustic waves in an unmagnetized electron–positron–ion–dust plasma with two-electron temperature distributions is investigated in the context of the nonextensive statistics. Using the reductive perturbation method, a modified nonlinear Schrödinger equation is derived for the potential wave amplitude. The effects of plasma parameters on the modulational instability of ion-acoustic waves are discussed in detail for planar as well as for cylindrical and spherical geometries. In addition, for the planar case, we analyze how the plasma parameters influence the nonlinear structures of the first- and second-order ion-acoustic rogue waves within the modulational instability region. The present results may be helpful in providing a good fit between the theoretical analysis and real applications in future spatial observations and laboratory plasma experiments. -- Highlights: ► Modulational instability of ion-acoustic waves in a new plasma model is discussed. ► Tsallis’s statistics is considered in the model. ► The second-order ion-acoustic rogue wave is studied for the first time.
Modulational instability of dust ion-acoustic waves in a magnetized dusty superthermal plasma
Shalini, A P Misra
2016-01-01
The amplitude modulation of three dimensional (3D) dust ion-acoustic wave (DIAW) packets is studied in a collisionless magnetized plasma with inertial positive ions, superthermal electrons and negatively charged immobile dust grains. By using the reductive perturbation technique, a 3D-nonlinear Schr{\\"o}dinger (NLS) equation is derived, which governs the slow modulation of DIAW packets. The latter are found to be stable in the low-frequency $(\\omega\\omega_c$, and the modulational instability (MI) is related to the modulational obliqueness $(\\theta)$. Here, $\\omega~(\\omega_c)$ is the nondimensional wave (ion-cyclotron) frequency. It is shown that the superthermal parameter $\\kappa$, the frequency $\\omega_c$ as well as the charged dust impurity $(0<\\mu<1)$ shift the MI domains around the $\\omega-\\theta$ plane, where $\\mu$ is the ratio of electron to ion number densities. Furthermore, it is found that the decay rate of instability is quenched by the superthermal parameter $\\kappa$ with cut-offs at lower wa...
Indian Academy of Sciences (India)
Uday Narayan Ghosh; Prasantha Chatterjee; Deb Kumar Ghosh
2013-10-01
Interaction of nonplanar ion-acoustic solitary waves is an important source of information for studying the nature and characteristics of ion-acoustic solitary waves (IASWs). The head-on collision between two cylindrical/spherical IASWs in un-magnetized plasmas comprising of nonthermal distributed electrons and warm ions is investigated using the extended version of Poincaré–Lighthill–Kuo (PLK) perturbation method. How the interactions are taking place in cylindrical and spherical geometries are shown numerically. Analytical phase shifts are derived for nonplanar geometry. The effects of the ion to electron temperature parameter and the nonthermal electrons parameter on the phase shift are studied. It is shown that the properties of the interaction of IASWs in different geometries are very different.
Dokgo, K.; Woo, M.; Choi, C.; Min, K. W.; Hwang, J.
2015-12-01
The generation of coherent ion acoustic solitary waves (IASWs) due to interactions between an electron hole (EH) and density gradient of plasma is investigated by both 1D particle-in-cell (PIC) simulation and theory. In our simulation, an EH is generated by plasma blob injection at the beginning. When the EH passes density gradient region, two features are observed: one is oscillations of EH bipolar field and another is IASWs generation. We found that these E field oscillations correspond to odd-symmetric trapped mode in the EH (OSTM). Using theoretical formalism introduced by Lewis, we theoretically derived the structure and the dispersion relation of OSTM. The OSTM structures calculated from simulation and theory are in good agreement. In the presence of density gradient, OSTM structure is distorted and become spatially asymmetric; its potential is weak in the higher density side and strong in the lower density side. Ions are pulled and pushed by the OSTM potential. As a results of potential difference, ions are accelerated to the lower density side then they formed IASWs. These process are repeated in the density gradient region when EH are passing, so IASWs are generated coherently.
Nonlinear ion-acoustic solitary waves in ion-beam plasma
Energy Technology Data Exchange (ETDEWEB)
Das, G.C.; Karmakar, B. (Manipur Univ., Imphal (India). Dept. of Mathematics); Singh, K.I. (Modern Coll., Imphal, Manipur (India))
1989-01-01
The dynamics of solitary waves in an ion-beam plasma having multiple electron temperatures are investigated. The investigation is based on the derivation of the Korteweg-de Vries (Kd V) equation by applying the reductive perturbation technique to the basic equations governing the plasma dynamics. Fascinating results are derived first for a plasma with a small percentage of non-isothermality, then the soliton's behaviour is obtained for an isothermal as well as for a non-isothermal plasma, and finally a general comparison is made and conclusions given. (author).
Head-on collision of dust-ion-acoustic solitons in electron-dust-ion quantum plasmas
Indian Academy of Sciences (India)
Prasanta Chatterjee; Malay Kumar Ghorui; Rajkumar Roychoudhury
2013-03-01
In this paper, we study the head-on collision between two dust-ion-acoustic (DIA) solitons in quantum electron-dust-ion plasma. Using the extended Poincaré–Lighthill–Kuo (PLK) method, we obtain the Korteweg–de Vries (KdV) equations, the phase shifts and the trajectories after the head-on collision of the two DIA solitons. We investigate the effect of quantum diffraction parameters for electrons and ions $(H_{e}, H_{i})$, the Fermi temperature ratio () and the dust charged number density (d0) on the phase shifts. Different values of = d0(d0/i0) and d = d0(i/d) are taken to discuss the effects on phase shifts, where d0 denotes the dust charge number, j0 represents the equilibrium number density and is the mass of the jth species ( = , , for electrons, ions and dust particles, respectively). It is observed that the phase shifts are significantly affected by the plasma parameters.
Indian Academy of Sciences (India)
WANG HONGYAN; ZHANG KAIBIAO
2016-07-01
The effects of dust size distribution and dust charge fluctuation of dust grains on the small but finite amplitude nonlinear dust ion-acoustic shock waves, in an unmagnetized multi-ion dusty plasma which contains negative ions, positive ions and electrons, are studied in this paper. A Burgers equation and its stationary solutions are obtained by using the reductive perturbation method. The analytical and numerical results show that the height with polynomial dust size distribution is larger than that of the monosized dusty plasmas with the same dustgrains, but the thickness in the case of different dust grains is smaller than that of the monosized dusty plasmas. Furthermore, the moving speed of the shock waves also depend on different dust size distributions.
Ion-acoustic solitary waves in ion-beam plasma with multiple-electron-temperatures
Energy Technology Data Exchange (ETDEWEB)
Karmakar, B.; Das, G.C.; Singh, Kh.I.
1988-08-01
The solitary wave solution has been studied in an ion-beam plasma with multiple-electron-temperatures stemmed through the derivation of a modified Korteweg-de Vries (KdV) equation. The evolution of solitons shows that the existence and the behaviour depend effectively on the ion-beam as well as on the multiple-electron-temperatures. It has been shown that the solitons might be large amplitude waves with the addition of a small percentage of ion-beam concentration or by the increase of electron-temperatures. The present investigators believe and conclude that the solitons should also show experimentally these fascinating properties but one has to be careful about the range of the physical parameters in ion-beam plasma.
Atamaniuk, B; Atamaniuk, Barbara; Zuchowski, Krzysztof
2007-01-01
There is a quickly increasing wealth of experimental data on so-called dusty plasmas i. e. ionized gases or usual plasmas that contain micron sized charged particles. Interest in these structures is driven both by their importance in many astrophysical as well as commercial situations. Among them are linear and nonlinear wave phenomena. We consider the influence of dust charge fluctuations on stability of the ion-acoustic waves when the stream of particles is present. It is assumed that all grains of dust have equal masses but charges are not constant in time-they may fluctuate in time. The dust charges are not really independent of the variations of the plasma potentials. All modes will influence the charging mechanism, and feedback will lead to several new interesting and unexpected phenomena. The charging of the grains depends on local plasma characteristics. If the waves disturb these characteristic, then charging of the grains is affected and the grain charge is modified, with a resulting feedback on the...
Energy Technology Data Exchange (ETDEWEB)
Hossen, M. R.; Nahar, L.; Mamun, A. A. [Jahangirnagar University,Savar, Dhaka (Bangladesh)
2014-12-15
The properties of time-dependent cylindrical and spherical, modified ion-acoustic (mIA) solitary structures in relativistic degenerate multi-ion plasmas (containing degenerate electron fluids, inertial positively-, as well as negatively-, charged light ions, and positively-charged static heavy ions) have been investigated theoretically. This investigation is valid for both non-relativistic and ultrarelativistic limits. The well-known reductive perturbation method has been used to derive the Korteweg-de Vries (K-dV) and the mK-dV equations for studying the basic features of solitary waves. The fundamental characteristics of mIA solitary waves are found to be significantly modified by the effects of the degenerate pressures of the electron and the ion fluids, their number densities, and the various charge states of heavy ions. The relevance of our results in astrophysical compact objects like white dwarfs and neutron stars, which are of scientific interest, is briefly discussed.
The collision effect between dust grains and ions to the dust ion acoustic waves in a dusty plasma
Energy Technology Data Exchange (ETDEWEB)
Yang Xue; Wang Canglong; Liu Congbo; Zhang Jianrong; Shi Yuren; Duan Wenshan [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yang Lei [College of Physics and Electronic Engineering and Joint Laboratory of Atomic and Molecular Physics of NWNU and IMP CAS, Northwest Normal University, Lanzhou 730070 (China) and Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Department of Physics, Lanzhou University, Lanzhou 730000 (China)
2012-10-15
Damping solitary wave in dusty plasma is studied by considering the collision effect between dust grains and ions. It can be described by a KdV type equation in which a damping term of {phi}{sup 2} exist. It is found that both the amplitude and propagation velocity of the solitary wave decrease with time exponentially. Our results are compared with another KdV type equation with the damping term of {phi}. It is noted that the damping rate of the KdV type equation with the damping term of {phi}{sup 2} is larger than that with the term of {phi}. It is found that the damping rate is proportional to the collision frequency between dust grains and ions.
Effect of nonthermal ion distribution and dust temperature on nonlinear dust-acoustic solitary waves
Indian Academy of Sciences (India)
K Annou; R Annou
2012-01-01
Dust-acoustic solitary waves in unmagnetized dusty plasma whose constituents are inertial charged dust grains, Boltzmannian electrons and nonthermal ions have been investigated by taking into account ﬁnite dust temperature. The pseudopotential has been used to study solitary solution. The existence of solitary waves having negative potential is reported.
A model for ion-acoustic solitary waves with streaming non-Maxwellian electrons in space plasmas
Khalid Hussain, Shah; Nouman Sarwar, Qureshi Muhammad
2016-04-01
Solitons are nonlinear solitary structures and are integral part of space plasmas. Such nonlinear structures, accompanied by streaming electrons are frequently observed by various satellites in different regions of near Earth plasmas such as Earth's bow shock, magnetopause, auroral zone, etc. In this paper, we present a fluid model consisting streaming non-Maxwellian electrons along the magnetic field and derived the Sagdeev potential for fully nonlinear fluid equations. We found that compressive solitons can be developed in such a plasma. The results from our model can be used to interpret solitary structures in space plasmas when there is streaming electron obeying the non-Maxwellian distributions
Paul, S. N.; Chatterjee, A.; Paul, Indrani
2017-01-01
Nonlinear propagation of ion-acoustic waves in self-gravitating multicomponent dusty plasma consisting of positive ions, non-isothermal two-temperature electrons and negatively charged dust particles with fluctuating charges and drifting ions has been studied using the reductive perturbation method. It has been shown that nonlinear propagation of ion-acoustic waves in gravitating dusty plasma is described by an uncoupled third order partial differential equation which is a modified form of Korteweg-deVries equation, in contraries to the coupled nonlinear equations obtained by earlier authors. Quasi-soliton solution for the ion-acoustic solitary wave has been obtained from this uncoupled nonlinear equation. Effects of non-isothermal two-temperature electrons, gravity, dust charge fluctuation and drift motion of ions on the ion-acoustic solitary waves have been discussed.
Nonlinear ion-acoustic solitary waves with warm ions and non-Maxwellian electrons in space plasmas
Hussain Shah, Khalid; Qureshi, Nouman
2017-04-01
Electrons velocity distributions are often observed with non-Maxwellian features such flat tops at low energies and/or superthermal tails at high energies from different regions of near Earth plasmas such as Earth's bow shock, auroral zone and magnetosphere by numerous satellites. Such non-Maxwellian distributions are well modelled by generalized (r,q) distribution or Cairns distribution. Solitons are nonlinear solitary structures and are integral part of space plasmas. In this paper, we present a fluid model containing Cairns (r,q) distributed non-Maxwellian electrons and derive the Sagdeev potential for fully nonlinear fluid equations. We found that compressive solitons can be developed in such a plasma. The results from our model can be used to interpret solitary structures in space plasmas when electrons are obeying the non-Maxwellian flat tops along with the high energy tails.
Alam, M. S.; Hafez, M. G.; Talukder, M. R.; Hossain Ali, M.
2017-07-01
A comparative study of the interactions between nonlinear ion acoustic solitary waves (IASWs) propagating toward each other, and the electrostatic nonlinear propagation of IASWs, both for the weakly and relativistic regimes consisting of relativistic warm ions, nonthermal electrons, and positrons, is carried out. Two-sided Korteweg-de Vries (KdV) equations are derived using the extended Poincaré-Lighthill-Kuo (PLK) method to reveal the physical issues concerned. The effects of positron concentration, ion-electron temperature ratio, electron-positron temperature ratio, relativistic streaming factor, the population of electron, and positron nonthermality on the electrostatic resonances and their phase shifts are investigated for both regimes. It is found that the plasma parameters significantly modify the phase shifts, electrostatic resonances, hump-shaped electrostatic potential profiles, and the electric fields on the nonlinear propagation characteristics of IASWs. The results obtained may be useful for clarifications of interaction between IASWs in astrophysical and laboratory plasmas, especially in pulsar magnetosphere, laser produced, inertial confinement plasmas, and pulsar relativistic winds with supernova ejecta that produce nonthermal electrons, positrons, and relativistic ions.
Dust-ion-acoustic double layers in multi-ion dusty plasma
Energy Technology Data Exchange (ETDEWEB)
Mamun, A. A. [Jahangirnagar University, Department of Physics (Bangladesh); Deeba, F., E-mail: farah.ju35@gmail.com [Dhaka University of Engineering and Technology, Department of Physics (Bangladesh)
2015-08-15
A theoretical investigation has been made on nonplanar (cylindrical and spherical) dust-ionacoustic (DIA) double layers (DLs) in a multi-ion dusty plasma system containing inertial positive and negative ions and arbitrarily charged stationary dust. The dust particles have been considered as arbitrarily (either positively or negatively) charged in order to observe the effects of the dust polarity on the DIA DLs. The ion species were considered to be at different temperatures to observe the effects of the temperatures on that waves. The modified Gardner equation, which has been derived by employing the reductive perturbation method, has been used to analyze time-dependent nonplanar and planar DIA DLs. It has been found that the time evolution of DIA DLs is significantly modified not only by the nonplanar geometry, but also by the polarity, temperature, and mass ratio of the constituent particles. It has been also found that the amplitude of cylindrical DIA DL structures is larger than that of 1D planar ones, but smaller than that of the spherical ones.
Singh, Manpreet; Singh Saini, Nareshpal; Ghai, Yashika; Kaur, Nimardeep
2016-07-01
Dusty plasma is a fully or partially ionized gas which contain micron or sub-micron sized dust particles. These dust particles can be positively or negatively charged, depending upon the mechanism of charging . Dusty plasma is often observed in most of the space and astrophysical plasma environments. Presence of these dust particles can modify the dispersion properties of waves in the plasma and can introduce several new wave modes, e.g., dust acoustic (DA) waves, dust-ion acoustic (DIA) waves, dust-acoustic shock waves etc. In this investigation we have studied the small amplitude dust acoustic waves in an unmagnetized plasma comprising of electrons, positively charged ions, negatively charged hot as well as cold dust. Electrons and ions are described by superthermal distribution which is more appropriate for modeling space and astrophysical plasmas. Kadomtsev- Petviashvili (KP) equation has been derived using reductive perturbation technique. Positive as well as negative potential structures are observed, depending upon some critical values of parameters. Amplitude and width of dust acoustic solitary waves are modified by varying these parameters such as superthermality of electrons and ions, direction of propagation of the wave, relative concentration of hot and cold dust particles etc. This study may be helpful in understanding the formation and dynamics of nonlinear structures in various space and astrophysical plasma environments such Saturn's F-rings.
Ion acoustic kinetic Alfvén rogue waves in two temperature electrons superthermal plasmas
Kaur, Nimardeep; Saini, N. S.
2016-10-01
The propagation properties of ion acoustic kinetic Alfvén (IAKA) solitary and rogue waves have been investigated in two temperature electrons magnetized superthermal plasma in the presence of dust impurity. A nonlinear analysis is carried out to derive the Korteweg-de Vries (KdV) equation using the reductive perturbation method (RPM) describing the evolution of solitary waves. The effect of various plasma parameters on the characteristics of the IAKA solitary waves is studied. The dynamics of ion acoustic kinetic Alfvén rogue waves (IAKARWs) are also studied by transforming the KdV equation into nonlinear Schrödinger (NLS) equation. The characteristics of rogue wave profile under the influence of various plasma parameters (κc, μc, σ , θ) are examined numerically by using the data of Saturn's magnetosphere (Schippers et al. 2008; Sakai et al. 2013).
Institute of Scientific and Technical Information of China (English)
Duan Wen-Shan
2004-01-01
The effect of dust charging and the influence of its adiabatic variation on dust acoustic waves is investigated. By employing the reductive perturbation technique we derived a Zakharov-Kuznetsov (ZK) equation for small amplitude dust acoustic waves. We have analytically verified that there are only rarefactive solitary waves for this system. The instability region for one-dimensional solitary wave under transverse perturbations has also been obtained. The obliquely propagating solitary waves to the z-direction for the ZK equation are given in this paper as well.
Large amplitude solitary waves in ion-beam plasmas with charged dust impurities
Misra, A P
2011-01-01
The nonlinear propagation of large amplitude dust ion-acoustic (DIA) solitary waves (SWs) in an ion-beam plasma with stationary charged dusts is investigated. For typical plasma parameters relevant for experiments [J. Plasma Phys. \\textbf{60}, 69 (1998)], when the beam speed is larger than the DIA speed ($v_{b0}\\gtrsim1.7c_s$), three stable waves, namely the "fast" and "slow" ion-beam modes and the plasma DIA wave are shown to exist. These modes can propagate as SWs in the beam plasmas. However, in the other regime ($c_s0)$ is found to be limited by a critical value which typically depends on $M$, $v_{b0}$ as well as the ion/beam temperature. The conditions for the existence of DIA solitons are obtained and their properties are analyzed numerically in terms of the system parameters. While the system supports both the compressive and rarefactive large amplitude SWs, the small amplitude solitons exist only of the compressive type. The theoretical results may be useful for observation of soliton excitations in l...
Indian Academy of Sciences (India)
S N Paul; S Chattopadhyaya; S K Bhattacharya; B Bera
2003-06-01
Using the pseudopotential method, theoretical investigation has been made on the ﬁrst-order Korteweg-deVries ion-acoustic solitons in a multicomponent plasma consisting of warm positive ions, negative ions and isothermal electrons. The effects of electron-inertia and drift motion of the ions on the amplitudes and widths of the solitons have been studied in a plasma having (H+, Cl-), (H+, O-), (He+, H-) and (He+, O-) ions. Ion-acoustic double-layers have also been investigated for such plasmas. It has been found that drift velocity and electron-inertia have signiﬁcant contribution on the formation of double-layers in multicomponent plasma.
Ion acoustic solitons/double layers in two-ion plasma revisited
Energy Technology Data Exchange (ETDEWEB)
Lakhina, G. S., E-mail: gslakhina@gmail.com; Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Kakad, A. P., E-mail: amar@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai 410218 (India)
2014-06-15
Ion acoustic solitons and double layers are studied in a collisionless plasma consisting of cold heavier ion species, a warm lighter ion species, and hot electrons having Boltzmann distributions by Sagdeev pseudo-potential technique. In contrast to the previous results, no double layers and super-solitons are found when both the heavy and lighter ion species are treated as cold. Only the positive potential solitons are found in this case. When the thermal effects of the lighter ion species are included, in addition to the usual ion-acoustic solitons occurring at M > 1 (where the Mach number, M, is defined as the ratio of the speed of the solitary wave and the ion-acoustic speed considering temperature of hot electrons and mass of the heavier ion species), slow ion-acoustic solitons/double layers are found to occur at low Mach number (M < 1). The slow ion-acoustic mode is actually a new ion-ion hybrid acoustic mode which disappears when the normalized number density of lighter ion species tends to 1 (i.e., no heavier species). An interesting property of the new slow ion-acoustic mode is that at low number density of the lighter ion species, only negative potential solitons/double layers are found whereas for increasing densities there is a transition first to positive solitons/double layers, and then only positive solitons. The model can be easily applicable to the dusty plasmas having positively charged dust grains by replacing the heavier ion species by the dust mass and doing a simple normalization to take account of the dust charge.
Institute of Scientific and Technical Information of China (English)
薛具奎; 郎和
2003-01-01
The effect of dust charge variation on the dust-acoustic solitary structures is investigated in a warm magnetized two-ion-temperature dusty plasma consisting of a negatively and variably charged extremely massive dust fluid and ions of two different temperatures. It is shown that the dust charge variation as well as the presence of a second component of ions would modify the properties of the dust-acoustic solitary structures and may excite both dust-acoustic solitary holes (soliton waves with a density dip) and positive solitons (soliton waves with a density hump).
Dust Acoustic Solitary Waves in Saturn F-ring's Region
Institute of Scientific and Technical Information of China (English)
E.K. El-Shewy; M.I. Abo el Maaty; H.G. Abdelwahed; M.A.Elmessary
2011-01-01
Effect of hot and cold dust charge on the propagation of dust-acoustic waves (DAWs) in unmagnetized plasma having electrons, singly charged ions, hot and cold dust grains has been investigated.The reductive perturbation method is employed to reduce the basic set of fluid equations to the Kortewege-de Vries (KdV) equation.At the critical hot dusty plasma density NhO, the KdV equation is not appropriate for describing the system.Hence, a set of stretched coordinates is considered to derive the modified KdV equation.It is found that the presence of hot and cold dust charge grains not only significantly modifies the basic properties of solitary structure, but also changes the polarity of the solitary profiles.In the vicinity of the critical hot dusty plasma density NhO, neither KdV nor mKdV equation is appropriate for describing the DAWs.Therefore, a further modified KdV (fmKdV) equation is derived, which admits both soliton and double layer solutions.
Indian Academy of Sciences (India)
Tarsem Singh Gill; Harvinder Kaur
2000-11-01
The effects of nonthermal ion distribution and ﬁnite dust temperature are incorporated in the investigation of nonlinear dust acoustic waves in an unmagnetized dusty plasma. Sagdeev pseudopotential method which takes into account the full nonlinearity of plasma equations, is used here to study solitary wave solutions. Possibility of co-existence of refractive and compressive solitons as a function of Mach number, dust temperature and concentration of nonthermal ions, is considered. For the ﬁxed value of nonthermal ions, it is found that the effect of increase in dust temperature is to reduce the range of co-existence of compressive and refractive solitons. Particular concentration of nonthermal ions results in disappearance of refractive solitons while the decrease in dust temperature, at this concentration restores the lost refractive solitons.
Experimental study of nonlinear dust acoustic solitary waves in a dusty plasma
Bandyopadhyay, P; Sen, A; Kaw, P K
2008-01-01
The excitation and propagation of finite amplitude low frequency solitary waves are investigated in an Argon plasma impregnated with kaolin dust particles. A nonlinear longitudinal dust acoustic solitary wave is excited by pulse modulating the discharge voltage with a negative potential. It is found that the velocity of the solitary wave increases and the width decreases with the increase of the modulating voltage, but the product of the solitary wave amplitude and the square of the width remains nearly constant. The experimental findings are compared with analytic soliton solutions of a model Kortweg-de Vries equation.
Energy Technology Data Exchange (ETDEWEB)
Ghosh, S. S., E-mail: sukti@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel, Navi Mumbai 410218 (India); Sekar Iyengar, A. N. [Plasma Physics Division, Saha Institute of Nuclear Physics, Kolkata 700064 (India)
2014-08-15
It is observed that the presence of a minority component of cooler electrons in a three component plasma plays a deterministic role in the evolution of solitary waves, double layers, or the newly discovered structures called supersolitons. The inclusion of the cooler component of electrons in a single electron plasma produces sharp increase in nonlinearity in spite of a decrease in the overall energy of the system. The effect maximizes at certain critical value of the number density of the cooler component (typically 15%–20%) giving rise to a hump in the amplitude variation profile. For larger amplitudes, the hump leads to a forbidden region in the ambient cooler electron concentration which dissociates the overall existence domain of solitary wave solutions in two distinct parameter regime. It is observed that an inclusion of the cooler component of electrons as low as < 1% affects the plasma system significantly resulting in compressive double layers. The solution is further affected by the cold to hot electron temperature ratio. In an adequately hotter bulk plasma (i.e., moderately low cold to hot electron temperature ratio), the parameter domain of compressive double layers is bounded by a sharp discontinuity in the corresponding amplitude variation profile which may lead to supersolitons.
Dust-acoustic solitary waves in a dusty plasma with two-temperature nonthermal ions
Indian Academy of Sciences (India)
Zhi-Jian Zhou; Hong-Yan Wang; Kai-Biao Zhang
2012-01-01
By using reductive perturbation method, the nonlinear propagation of dust-acoustic waves in a dusty plasma (containing a negatively charged dust ﬂuid, Boltzmann distributed electrons and two-temperature nonthermal ions) is investigated. The effects of two-temperature nonthermal ions on the basic properties of small but ﬁnite amplitude nonlinear dust-acoustic waves are examined. It is found that two-temperature nonthermal ions affect the basic properties of the dust-acoustic solitary waves. It is also observed that only compressive solitary waves exist in this system.
Interaction of solitary waves in magnetized warm dusty plasmas with dust charging effects
Institute of Scientific and Technical Information of China (English)
Xue Ju-Kui
2006-01-01
In consideration of adiabatic dust charge variation, the combined effect of the external magnetized field and the dust temperature on head-on collision of the three-dimensional dust acoustic solitary waves is investigated. By using the extended Poincaré-Lighthill-Kuo method, the phase shifts and the trajectories of two solitons after the collision are obtained. The effects of the magnitude and the obliqueness of the external magnetic field and the dust temperature on the solitary wave collisions are discussed in detail.
Dust acoustic solitary and shock excitations in a Thomas-Fermi magnetoplasma
Energy Technology Data Exchange (ETDEWEB)
Rahim, Z.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Ali, S. [National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)
2014-07-15
The linear and nonlinear properties of dust-acoustic waves are investigated in a collisionless Thomas-Fermi magnetoplasma, whose constituents are electrons, ions, and negatively charged dust particles. At dust time scale, the electron and ion number densities follow the Thomas-Fermi distribution, whereas the dust component is described by the classical fluid equations. A linear dispersion relation is analyzed to show that the wave frequencies associated with the upper and lower modes are enhanced with the variation of dust concentration. The effect of the latter is seen more strongly on the upper mode as compared to the lower mode. For nonlinear analysis, we obtain magnetized Korteweg-de Vries (KdV) and Zakharov-Kuznetsov (ZK) equations involving the dust-acoustic solitary waves in the framework of reductive perturbation technique. Furthermore, the shock wave excitations are also studied by allowing dissipation effects in the model, leading to the Korteweg-de Vries-Burgers (KdVB) and ZKB equations. The analysis reveals that the dust-acoustic solitary and shock excitations in a Thomas-Fermi plasma are strongly influenced by the plasma parameters, e.g., dust concentration, dust temperature, obliqueness, magnetic field strength, and dust fluid viscosity. The present results should be important for understanding the solitary and shock excitations in the environments of white dwarfs or supernova, where dust particles can exist.
Institute of Scientific and Technical Information of China (English)
XueJu-Kui; LangHe
2003-01-01
The effect of dust charge variation on the dust-acoustic solitary structures is investigated in a warm magnetized two-ion-temperature dusty plasma consisting of a negatively and variably charged extremely massive dust fluid and ions of two different temperatures. It is shown that the dust charge variation as well as the presence of a second component of ions would modify the properties of the dust-acoustic solitary structures and may exite both dust-acoustic solitary holes (soliton waves with a density dip) and positive solitons (soliton waves with a density hump).
Solitary waves in a self-gravitating opposite polarity dust-plasma medium
Energy Technology Data Exchange (ETDEWEB)
Mamun, A. A.; Schlickeiser, R. [Institut für Theoretische Physik, Lehrstuhl IV, Fakultät für Physik und Astronomie, Ruhr-Universität Bochum, D-44780 Bochum (Germany)
2015-10-15
A more general and realistic dusty plasma model, namely, self-gravitating opposite polarity dust-plasma system (containing inertial positive and negative dust, and inertialess ions and electrons following Maxwellian distribution) is considered. The possibility for the formation of solitary electrostatic and self-gravitational potential structures in such a dust-plasma system is thoroughly examined. The standard reductive perturbation method, which is valid for small but finite amplitude solitary structures, is employed. The parametric regimes for the existence of solitary electrostatic and self-gravitational potential structures, and their basic properties (viz., polarity, amplitude, width, and speed) are found to be significantly modified by the combined effects of positively charged dust component and self-gravitational field. The applications of the present investigation in different space dusty plasma environments and laboratory dusty plasma devices are briefly discussed.
Oblique solitary waves in a five component plasma
Energy Technology Data Exchange (ETDEWEB)
Sijo, S.; Manesh, M.; Sreekala, G.; Venugopal, C., E-mail: cvgmgphys@yahoo.co.in [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, 686 560 Kerala (India); Neethu, T. W. [Department of Physics, CMS College, Mahatma Gandhi University, Kottayam, 686 001 Kerala (India); Renuka, G. [Kerala State Council for Science, Technology and Environment, Thiruvananthapuram, 695 004 Kerala (India)
2015-12-15
We investigate the influence of a second electron component on oblique dust ion acoustic solitary waves in a five component plasma consisting of positively and negatively charged dust, hydrogen ions, and hotter and colder electrons. Of these, the heavier dust and colder photo-electrons are of cometary origin while the other two are of solar origin; electron components are described by kappa distributions. The K-dV equation is derived, and different attributes of the soliton such as amplitude and width are plotted for parameters relevant to comet Halley. We find that the second electron component has a profound influence on the solitary wave, decreasing both its amplitude and width. The normalized hydrogen density strongly influences the solitary wave by decreasing its width; the amplitude of the solitary wave, however, increases with increasing solar electron temperatures.
Soliton Collisions in the Ion Acoustic Plasma Equations
Li, Y; Li, Yi
1999-01-01
Numerical experiments involving the interaction of two solitary waves of the ion acoustic plasma equations are described. An exact 2-soliton solution of the relevant KdV equation was fitted to the initial data, and good agreement was maintained throughout the entire interaction. The data demonstrates that the soliton interactions are virtually elastic
Semi-analytic variable charge solitary waves involving dust phase-space vortices (holes)
Energy Technology Data Exchange (ETDEWEB)
Tribeche, Mouloud; Younsi, Smain; Amour, Rabia; Aoutou, Kamel [Plasma Physics Group, Faculty of Sciences-Physics, Theoretical Physics Laboratory, University of Bab-Ezzouar, USTHB BP 32, El Alia, Algiers 16111 (Algeria)], E-mail: mtribeche@usthb.dz
2009-09-15
A semi-analytic model for highly nonlinear solitary waves involving dust phase-space vortices (holes) is outlined. The variable dust charge is expressed in terms of the Lambert function and we take advantage of this transcendental function to investigate the localized structures that may occur in a dusty plasma with variable charge trapped dust particles. Our results which complement the previously published work on this problem (Schamel et al 2001 Phys. Plasmas 8 671) should be of basic interest for experiments that involve the trapping of dust particles in ultra-low-frequency dust acoustic modes.
Propagation of Ion Acoustic Perturbations
DEFF Research Database (Denmark)
Pécseli, Hans
1975-01-01
Equations describing the propagation of ion acoustic perturbations are considered, using the assumption that the electrons are Boltzman distributed and isothermal at all times. Quasi-neutrality is also considered.......Equations describing the propagation of ion acoustic perturbations are considered, using the assumption that the electrons are Boltzman distributed and isothermal at all times. Quasi-neutrality is also considered....
Indian Academy of Sciences (India)
O Rahman; A A Mamun
2013-06-01
A theoretical investigation of dust-acoustic solitary waves in three-component unmagnetized dusty plasma consisting of trapped electrons, Maxwellian ions, and arbitrarily charged cold mobile dust was done. It has been found that, owing to the departure from the Maxwellian electron distribution to a vortex-like one, the dynamics of small but finite amplitude dust-acoustic (DA) waves is governed by a nonlinear equation of modified Korteweg–de Vries (mKdV) type (instead of KdV). The reductive perturbation method was employed to study the basic features (amplitude, width, speed, etc.) of DA solitary waves which are significantly modified by the presence of trapped electrons. The implications of our results in space and laboratory plasmas are briefly discussed.
Deka, Manoj Kr.
2016-12-01
In this report, a detailed investigation on the study of dust acoustics solitary waves solution with negatively dust charge fluctuation in dusty plasma corresponding to lower and higher temperature nonthermal ions with trapped electrons is presented. We consider temporal variation of dust charge as a source of dissipation term to derive the lower order modified Kadomtsev-Petviashvili equation by using the reductive perturbation technique. Solitary wave solution is obtained with the help of sech method in presence of trapped electrons and low (and high) temperature nonthermal ions. Both nonthermality of ions and trapped state of the electrons are found to have an imperative control on the nonlinear coefficient, dissipative coefficient as well as height of the wave potential.
Propagation of ion-acoustic waves in a dusty plasma with non-isothermal electrons
Indian Academy of Sciences (India)
K K Mondal
2007-08-01
For an unmagnetised collisionless plasma consisting of warm ions, non-isothermal electrons and cold, massive and charged dust grains, the Sagdeev potential equation, considering both ion dynamics and dust dynamics has been derived. It has been observed that the Sagdeev potential () exists only for > 0 up to an upper limit ( ≃ 1.2). This implies the possibility of existence of compressive solitary wave in the plasma. Exhaustive numerics done for both the large-amplitude and small-amplitude ion-acoustic waves have revealed that various parameters, namely, ion temperature, non-isothermality of electrons, Mach numbers etc. have considerable impact on the amplitude as well as the width of the solitary waves. Dependence of soliton profiles on the ion temperature and the Mach number has also been graphically displayed. Moreover, incorporating dust-charge fluctuation and non-isothermality of electrons, a non-linear equation relating the grain surface potential to the electrostatic potential has been derived. It has been solved numerically and interdependence of the two potentials for various ion temperatures and orders of non-isothermality has been shown graphically.
Ion acoustic solitons in a solar wind magnetoplasma with Kappa distributed electrons
Devanandhan, Selvaraj; Singh, Satyavir; Singh Lakhina, Gurbax; Sreeraj, T.
2016-07-01
In many space plasma environments, the velocity distribution of particles often deviates from Maxwellian and is well-modelled by a kappa distribution function. We have analyzed the ion acoustic soliton in a magnetized consisting of plasma Protons, Helium ions, an electron beam and superthermal hot electrons following kappa distribution function. Under the assumption of weak nonlinearity, the ion-acoustic solitons are described by the Korteweg-de-Vries-Zakharov-Kuznetsov (KdV-ZK) equation. The solution of KdV-ZK equation is used to model the characteristics of the ion acoustic solitary waves in a solar wind magnetoplasma observed at 1 AU. We have found both slow and fast ion acoustic solitons in our study. It is found that the superthermality of hot electrons greatly influence the existence regime of the solitary waves. The numerical results of this study to explain solar wind observations will be discussed in detail.
Dust-acoustic solitary waves in a magnetized dusty plasma with nonthermal electrons and trapped ions
Misra, A. P.; Wang, Yunliang
2015-05-01
The nonlinear propagation of electrostatic dust-acoustic (DA) waves in a magnetized dusty plasma consisting of negatively charged mobile dusts, nonthermal fast electrons and trapped ions with vortex-like distribution is studied. Using the reductive perturbation technique, a Korteweg-de Vries (KdV)-like equation is derived which governs the dynamics of the small-amplitude solitary waves in a magnetized dusty nonthermal plasma. It is found that due to the dust thermal pressure, there exists a critical value (βc) of the nonthermal parameter β (>1), denoting the percentage of energetic electrons, below which the DA solitary waves cease to propagate. The soliton solution (traveling wave) of the KdV-like equation is obtained, and is shown to be only of the rarefactive type. The properties of the solitons are analyzed numerically with the system parameters. It is also seen that the effect of the static magnetic field (which only modifies the soliton width) becomes significant when the dust gyrofrequency is smaller than one-tenth of the dust plasma frequency. Furthermore, the amplitude of the soliton is found to increase (decrease) when the ratio of the free to trapped ion temperatures (σ) is positive (negative). The effects of the system parameters including the obliqueness of propagation (lz) and σ on the dynamics of the DA solitons are also discussed numerically, and it is found that the soliton structures can withstand perturbations and turbulence during a considerable time. The results should be useful for understanding the nonlinear propagation of DA solitary waves in laboratory and space plasmas (e.g., Earth's magnetosphere, auroral region, heliospheric environments, etc.).
Dust-acoustic solitary waves in a magnetized dusty plasma with nonthermal electrons and trapped ions
Misra, A P
2014-01-01
The nonlinear theory of electrostatic dust-acoustic (DA) waves in a magnetized dusty plasma consisting of negatively charged mobile dusts, nonthermal fast electrons and trapped ions with vortex-like distribution is revisited. Previous theory in the literature [Phys. Plasmas {\\bf 20}, 104505 (2013)] is rectified and put forward to include the effects of the external magnetic field, the adiabatic pressure of charged dusts as well as the obliqueness of propagation to the magnetic field. Using the reductive perturbation technique, a Korteweg-de Vries (KdV)-like equation is derived which governs the dynamics of the small-amplitude solitary waves in a magnetized dusty nonthermal plasma. It is found that due to the dust thermal pressure, there exists a critical value $(\\beta_c)$ of the nothermal parameter $\\beta (>1)$, denoting the percentage of energetic electrons, below which the DA solitary waves cease to propagate. The soliton solution (travelling wave) of the KdV-like equation is obtained, and is shown to be on...
Dust-acoustic solitary waves and shocks in strongly coupled quantum plasmas
Wang, Y
2014-01-01
We investigate the propagation characteristics of electrostatic dust-acoustic (DA) solitary waves and shocks in a strongly coupled dusty plasma consisting of intertialess electrons and ions, and strongly coupled inertial charged dust particles. A generalized viscoelastic hydrodynamic model with the effects of electrostatic dust pressure associated with the strong coupling of dust particles, and a quantum hydrodynamic model with the effects of quantum forces associated with the Bohm potential and the exchange-correlation potential for electrons and ions are considered. Both the linear and weakly nonlinear theory of DA waves are studied by the derivation and analysis of dispersion relations as well as Korteweg-de Vries (KdV) and KdV-Burgers (KdVB)-like equations. It is shown that in the kinetic regime ($\\omega\\tau_m\\gg1$, where $\\omega$ is the wave frequency and $\\tau_m$ is the viscoelastic relaxtation time), the amplitude of the DA solitary waves decays slowly with time with the effect of a small amount of dus...
Webb, G M; Ao, X; Zank, G P
2013-01-01
Models for travelling waves in multi-fluid plasmas give essential insight into fully nonlinear wave structures in plasmas, not readily available from either numerical simulations or from weakly nonlinear wave theories. We illustrate these ideas using one of the simplest models of an electron-proton multi-fluid plasma for the case where there is no magnetic field or a constant normal magnetic field present. We show that the travelling waves can be reduced to a single first order differential equation governing the dynamics. We also show that the equations admit a multi-symplectic Hamiltonian formulation in which both the space and time variables can act as the evolution variable. An integral equation useful for calculating adiabatic, electrostatic solitary wave signatures for multi-fluid plasmas with arbitrary mass ratios is presented. The integral equation arises naturally from a fluid dynamics approach for a two fluid plasma, with a given mass ratio of the two species (e.g. the plasma could be an electron pr...
Dust-acoustic solitary waves in dusty plasma with variable dust charge
Forozani, Gh
2011-01-01
In this article we are going to consider dust acoustic wave in dusty plasma whose constituents are inertial negative charged dust particles, Boltzmann distributed electrons and non-thermal distributed ions with variable dust charge. Using reductive perturbation method, we have obtained Korteweg-de Veries (kdv) and modified kdv(mkdv) equations. A Sagdeev potential for the system and stability conditions for solitonic solution are also derived.
Dust kinetic Alfvén solitary and rogue waves in a superthermal dusty plasma
Energy Technology Data Exchange (ETDEWEB)
Saini, N. S., E-mail: nssaini@yahoo.com; Singh, Manpreet, E-mail: singhmanpreet185@gmail.com [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India); Bains, A. S., E-mail: bainsphysics@yahoo.co.in [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada)
2015-11-15
Dust kinetic Alfvén solitary waves (DKASWs) have been examined in a low-β dusty plasma comprising of negatively charged dust grains, superthermal electrons, and ions. A nonlinear Korteweg-de Vries (KdV) equation has been derived using the reductive perturbation method. The combined effects of superthermality of charged particles (via κ), plasma β, obliqueness of propagation (θ), and dust concentration (via f) on the shape and size of the DKASWs have been examined. Only negative potential (rarefactive) structures are observed. Further, characteristics of dust kinetic Alfvén rogue waves (DKARWs), by deriving the non-linear Schrödinger equation (NLSE) from the KdV equation, are studied. Rational solutions of NLSE show that rogue wave envelopes are supported by this plasma model. It is observed that the influence of various plasma parameters (superthermality, plasma β, obliqueness, and dust concentration) on the characteristics of the DKARWs is very significant. This fundamental study may be helpful in understanding the formation of coherent nonlinear structures in space and astrophysical plasma environments where superthermal particles are present.
Institute of Scientific and Technical Information of China (English)
CHEN Jian-Hong; WEI Nan-Xia
2009-01-01
Taking into account the combined effects of the external magnetic field, adiabatic dust charge fluctuation and collisions occurring between the charged dust gains and neutral gas particles (dust-neutral collisions), the dust-acoustic solitary waves in three-dimensional uniform dusty plasmas are investigated analytically. By using the reductive perturbation method, the Korteweg-de Vries (KdV) equation governing the dust-acoustic solitary waves is obtained. The present analytical results show that only rarefactive solitary waves exist in this system. It is also found that the effects of the wave vector along the z-direction, dust charge variation, collisional frequency, the plasma density, and temperature ratio can significantly influence the characteristics of low-frequency wave modes. Moreover, for the collisional dusty plasmas, there is a certain critical value μc of the plasma density ratio #, if μ < μc, the width of the waves increases with μ, otherwise the width of waves decreases with μ.
Landau damping effects on dust-acoustic solitary waves in a dusty negative-ion plasma
Energy Technology Data Exchange (ETDEWEB)
Barman, Arnab; Misra, A. P., E-mail: apmisra@visva-bharati.ac.in, E-mail: apmisra@gmail.com [Department of Mathematics, Siksha Bhavana, Visva-Bharati University, Santiniketan 731 235, West Bengal (India)
2014-07-15
The nonlinear theory of dust-acoustic waves (DAWs) with Landau damping is studied in an unmagnetized dusty negative-ion plasma in the extreme conditions when the free electrons are absent. The cold massive charged dusts are described by fluid equations, whereas the two-species of ions (positive and negative) are described by the kinetic Vlasov equations. A Korteweg-de Vries (KdV) equation with Landau damping, governing the dynamics of weakly nonlinear and weakly dispersive DAWs, is derived following Ott and Sudan [Phys. Fluids 12, 2388 (1969)]. It is shown that for some typical laboratory and space plasmas, the Landau damping (and the nonlinear) effects are more pronounced than the finite Debye length (dispersive) effects for which the KdV soliton theory is not applicable to DAWs in dusty pair-ion plasmas. The properties of the linear phase velocity, solitary wave amplitudes (in presence and absence of the Landau damping) as well as the Landau damping rate are studied with the effects of the positive ion to dust density ratio (μ{sub pd}) as well as the ratios of positive to negative ion temperatures (σ) and masses (m)
Indian Academy of Sciences (India)
ALY R SEADAWY
2017-09-01
Nonlinear two-dimensional Kadomtsev–Petviashvili (KP) equation governs the behaviour of nonlinear waves in dusty plasmas with variable dust charge and two temperature ions. By using the reductive perturbation method, the two-dimensional dust-acoustic solitary waves (DASWs) in unmagnetized cold plasma consisting of dust fluid, ions and electrons lead to a KP equation. We derived the solitary travelling wave solutions of the twodimensional nonlinear KP equation by implementing sech–tanh, sinh–cosh, extended direct algebraic and fraction direct algebraicmethods. We found the electrostatic field potential and electric field in the form travellingwave solutions for two-dimensional nonlinear KP equation. The solutions for the KP equation obtained by using these methods can be demonstrated precisely and efficiency. As an illustration, we used the readymade package of $\\it{Mathematica}$ program 10.1 to solve the original problem. These solutions are in good agreement with the analytical one.
Nonplanar Ion-Acoustic Solitons in Electron-Positron-Ion Quantum Plasmas
Institute of Scientific and Technical Information of China (English)
S. A. Khan; S. Mahmood; Arshad M. Mirza
2009-01-01
@@ The propagation of nonplanar quantum ion-acoustic solitary waves in a dense, unmagnetized electron-positron-ion (e-p-i) plasma are studied by using the Korteweg-de Vries (KdV) model The quantum hydrodynamic (QHD) equations are used taking into account the quantum diffraction and quantum statistics corrections. The analytical and numerical solutions of KdV equation reveal that the nonplanar ion-acoustic solitons are modified significantly with quantum corrections and positron concentration, and behave differently in different geometries.
On Collisionless Damping of Ion Acoustic Waves
DEFF Research Database (Denmark)
Jensen, Vagn Orla; Petersen, P.I.
1973-01-01
Exact theoretical treatments show that the damping of ion acoustic waves in collisionless plasmas does not vanish when the derivative of the undisturbed distribution function at the phase velocity equals zero.......Exact theoretical treatments show that the damping of ion acoustic waves in collisionless plasmas does not vanish when the derivative of the undisturbed distribution function at the phase velocity equals zero....
Landau damping effects on dust-acoustic solitary waves in a dusty negative-ion plasma
Barman, A
2014-01-01
The nonlinear theory of dust-acoustic waves (DAWs) with Landau damping is studied in an unmagnetized dusty negative-ion plasma in the extreme conditions when the free electrons are absent. The cold massive charged dusts are described by fluid equations, whereas the two-species of ions (positive and negative) are described by the kinetic Vlasov equations. A Korteweg de-Vries (KdV) equation with Landau damping, governing the dynamics of weakly nonlinear and weakly dispersive DAWs, is derived following Ott and Sudan [Phys. Fluids {\\bf 12}, 2388 (1969)]. It is shown that for some typical laboratory and space plasmas, the Landau damping (and the nonlinear) effects are more pronounced than the finite Debye length (dispersive) effects for which the KdV soliton theory is not applicable to DAWs in dusty pair-ion plasmas. The properties of the linear phase velocity, solitary wave amplitudes (in presence and absence of the Landau damping) as well as the Landau damping rate are studied with the effects of the positive io...
Nonlinear ion-acoustic cnoidal waves in a dense relativistic degenerate magnetoplasma
El-Shamy, E. F.
2015-03-01
The complex pattern and propagation characteristics of nonlinear periodic ion-acoustic waves, namely, ion-acoustic cnoidal waves, in a dense relativistic degenerate magnetoplasma consisting of relativistic degenerate electrons and nondegenerate cold ions are investigated. By means of the reductive perturbation method and appropriate boundary conditions for nonlinear periodic waves, a nonlinear modified Korteweg-de Vries (KdV) equation is derived and its cnoidal wave is analyzed. The various solutions of nonlinear ion-acoustic cnoidal and solitary waves are presented numerically with the Sagdeev potential approach. The analytical solution and numerical simulation of nonlinear ion-acoustic cnoidal waves of the nonlinear modified KdV equation are studied. Clearly, it is found that the features (amplitude and width) of nonlinear ion-acoustic cnoidal waves are proportional to plasma number density, ion cyclotron frequency, and direction cosines. The numerical results are applied to high density astrophysical situations, such as in superdense white dwarfs. This research will be helpful in understanding the properties of compact astrophysical objects containing cold ions with relativistic degenerate electrons.
Nonlinear propagation of weakly relativistic ion-acoustic waves in electron–positron–ion plasma
Indian Academy of Sciences (India)
M G HAFEZ; M R TALUKDER; M HOSSAIN ALI
2016-11-01
This work presents theoretical and numerical discussion on the dynamics of ion-acoustic solitary wave for weakly relativistic regime in unmagnetized plasma comprising non-extensive electrons, Boltzmann positrons and relativistic ions. In order to analyse the nonlinear propagation phenomena, the Korteweg–de Vries(KdV) equation is derived using the well-known reductive perturbation method. The integration of the derived equation is carried out using the ansatz method and the generalized Riccati equation mapping method. The influenceof plasma parameters on the amplitude and width of the soliton and the electrostatic nonlinear propagation of weakly relativistic ion-acoustic solitary waves are described. The obtained results of the nonlinear low-frequencywaves in such plasmas may be helpful to understand various phenomena in astrophysical compact object and space physics.
Ion-acoustic solitons in an inhomogeneous multicomponent plasma with negative ions
Energy Technology Data Exchange (ETDEWEB)
Das, G.C.; Singh, S.S. (Dept. of Mathematics, Manipur Univ., Imphal 795 003 (IN))
1992-02-01
Ion-acoustic solitary waves are studied in an inhomogeneous multicomponent plasma by the augmentation of a K-dV equation wherein a simple form of ionization has been taken to show its interaction in changing the salient features of the soliton, as compared to those observed in a homogeneous plasma. As expected, the negative ions in the plasma bring here a drastic alteration on the ion-acoustic solitons, thereby establishing a new era by showing the solitary waves to be studied by a modified K-dV equation. This paper reports that the main emphasis has been as to how the ionization and density gradient in the imhomogeneous plasma affect the solitons.
Quantum corrections to nonlinear ion acoustic wave with Landau damping
Energy Technology Data Exchange (ETDEWEB)
Mukherjee, Abhik; Janaki, M. S. [Saha Institute of Nuclear Physics, Calcutta (India); Bose, Anirban [Serampore College, West Bengal (India)
2014-07-15
Quantum corrections to nonlinear ion acoustic wave with Landau damping have been computed using Wigner equation approach. The dynamical equation governing the time development of nonlinear ion acoustic wave with semiclassical quantum corrections is shown to have the form of higher KdV equation which has higher order nonlinear terms coming from quantum corrections, with the usual classical and quantum corrected Landau damping integral terms. The conservation of total number of ions is shown from the evolution equation. The decay rate of KdV solitary wave amplitude due to the presence of Landau damping terms has been calculated assuming the Landau damping parameter α{sub 1}=√(m{sub e}/m{sub i}) to be of the same order of the quantum parameter Q=ℏ{sup 2}/(24m{sup 2}c{sub s}{sup 2}L{sup 2}). The amplitude is shown to decay very slowly with time as determined by the quantum factor Q.
Saini, N. S.; Kaur, Barjinder; Singh, Manpreet; Bains, A. S.
2017-07-01
A theoretical investigation is carried out to study small amplitude dust kinetic Alfvén solitary waves (DKASWs) and rogue waves in a low-β, electron depleted plasma consisting of negatively charged dust grains and two temperature ions which are modelled by q-nonextensive distribution. A nonlinear Korteweg-de Vries equation, which governs the evolution of DKASWs, has been derived using the reductive perturbation method. Combined effects of the nonextensivity of ions, plasma beta, temperature ratio of low and high temperature ions, concentration of ions as well as dust, and angle of propagation (θ) have been studied in detail on the propagation properties of DKASWs. Only negative potential Alfvénic solitary waves are observed in the present study. Further, the study is extended for dust kinetic Alfvén rogue wave (DKARW) solutions. The properties of DKARWs, influenced by plasma parameters in question, are discussed in detail. The findings of this study may be useful to understand the formation of nonlinear coherent structures in Saturn's F-ring.
Nonlinear ion-acoustic waves in a degenerate plasma with nuclei of heavy elements
Energy Technology Data Exchange (ETDEWEB)
Hossen, M. A., E-mail: armanplasma@gmail.com; Mamun, A. A., E-mail: mamun-phys@yahoo.co.uk [Department of Physics, Jahangirnagar University, Savar, Dhaka-1342 (Bangladesh)
2015-10-15
The ion-acoustic (IA) solitary waves propagating in a fully relativistic degenerate dense plasma (containing relativistic degenerate electron and ion fluids, and immobile nuclei of heavy elements) have been theoretically investigated. The relativistic hydrodynamic model is used to derive the Korteweg-de Vries (K-dV) equation by the reductive perturbation method. The stationary solitary wave solution of this K-dV equation is obtained to characterize the basic features of the IA solitary structures that are found to exist in such a degenerate plasma. It is found that the effects of electron dynamics, relativistic degeneracy of the plasma fluids, stationary nuclei of heavy elements, etc., significantly modify the basic properties of the IA solitary structures. The implications of this results in astrophysical compact objects like white dwarfs are briefly discussed.
Institute of Scientific and Technical Information of China (English)
U.A.Mofiz; R.Battiston
2009-01-01
The data of ionospheric perturbations observed on DEMETER before the 2007 Pu'er earthquake are analyzed. The three-component plasma (ions, electrons and heavy ions) is studied in the fluid concept. The linear dispersion relation for ion-acoustic wave is found in the presence of heavy ions. The nonlinear dynamics is studied for arbitrary amplitude of the wave. The Sagdeev potential is calculated, which shows that solitary structure exists for Mach number within a range defined by the presence of heavy ions. The developed ion-acoustic solitons may be used as precursor for earthquake prediction.
Dust acoustic solitary and shock waves in strongly coupled dusty plasmas with nonthermal ions
Indian Academy of Sciences (India)
Hamid Reza Pakzad; Kurosh Javidan
2009-11-01
The Korteweg–de Vries–Burgers (KdV–Burgers) equation and modified Korteweg–de Vries–Burgers equation are derived in strongly coupled dusty plasmas containing nonthermal ions and Boltzmann distributed electrons. It is found that solitary waves and shock waves can be produced in this medium. The effects of important parameters such as ion nonthermal parameter, temperature, density and velocity on the properties of shock waves and solitary waves are discussed.
A Schamel equation for ion acoustic waves in superthermal plasmas
Energy Technology Data Exchange (ETDEWEB)
Williams, G., E-mail: gwilliams06@qub.ac.uk; Kourakis, I. [Centre for Plasma Physics, Department of Physics and Astronomy, Queen' s University Belfast, BT7 1NN, Northern Ireland (United Kingdom); Verheest, F. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, B-9000 Gent (Belgium); School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000 (South Africa); Hellberg, M. A. [School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000 (South Africa); Anowar, M. G. M. [Department of Physics, Begum Rokeya University, Rangpur, Rangpur-5400 (Bangladesh)
2014-09-15
An investigation of the propagation of ion acoustic waves in nonthermal plasmas in the presence of trapped electrons has been undertaken. This has been motivated by space and laboratory plasma observations of plasmas containing energetic particles, resulting in long-tailed distributions, in combination with trapped particles, whereby some of the plasma particles are confined to a finite region of phase space. An unmagnetized collisionless electron-ion plasma is considered, featuring a non-Maxwellian-trapped electron distribution, which is modelled by a kappa distribution function combined with a Schamel distribution. The effect of particle trapping has been considered, resulting in an expression for the electron density. Reductive perturbation theory has been used to construct a KdV-like Schamel equation, and examine its behaviour. The relevant configurational parameters in our study include the superthermality index κ and the characteristic trapping parameter β. A pulse-shaped family of solutions is proposed, also depending on the weak soliton speed increment u{sub 0}. The main modification due to an increase in particle trapping is an increase in the amplitude of solitary waves, yet leaving their spatial width practically unaffected. With enhanced superthermality, there is a decrease in both amplitude and width of solitary waves, for any given values of the trapping parameter and of the incremental soliton speed. Only positive polarity excitations were observed in our parametric investigation.
Dynamic motions of ion acoustic waves in plasmas with superthermal electrons
Energy Technology Data Exchange (ETDEWEB)
Saha, Asit, E-mail: asit_saha123@rediffmail.com [Department of Mathematics, Sikkim Manipal Institute of Technology (India); Chatterjee, Prasanta [Department of Mathematics, Siksha Bhavana, Visva Bharati University (India); Wong, C.S. [Plasma Technology Research Centre, Department of Physics, University of Malaya, Kuala Lampur (Malaysia)
2015-12-15
The dynamic motions of ion acoustic waves an unmagnetized plasma with superthermal (q-non extensive) electrons are investigated employing the bifurcation theory of planar dynamical systems through direct approach. Using traveling wave transformation and initial conditions, basic equations are transformed to a planar dynamical system. Using numerical computations, all possible phase portraits of the dynamical system are presented. Corresponding to homoclinic and periodic orbits of the phase portraits, two new analytical forms of solitary and periodic wave solutions are derived depending on the non extensive parameter q and speed v of the traveling wave. Considering an external periodic perturbation, the quasiperiodic and chaotic motions of ion acoustic waves are presented. Depending upon different ranges of non extensive parameter q, the effect of q is shown on quasiperiodic and chaotic motions of ion acoustic waves with fixed value of v. It is seen that the unperturbed dynamical system has the solitary and periodic wave solutions, but the perturbed dynamical system has the quasiperiodic and chaotic motions with same values of parameters q and v. (author)
Interaction of ion-acoustic solitons with electron beam in warm plasmas with superthermal electrons
Esfandyari-Kalejahi, A R
2012-01-01
Propagation of ion-acoustic solitary waves (IASWs) is studied using the hydrodynamic equations coupled with the Poisson equation in a warm plasma consisting of adiabatic ions and superthermal (Kappa distributed) electrons in presence of an electron-beam component. In the linear limit, the dispersion relation for ion-acoustic (IA) waves is obtained by linearizing of basic equations. On the other hand, in the nonlinear analysis, an energy-balance like equation involving Sagdeev's pseudo-potential is derived in order to investigate arbitrary amplitude IA solitons. The Mach number range is determined in which, propagation and characteristics of IA solitons are analyzed both parametrically and numerically. The variation of amplitude and width of electrostatic (ES) excitations as a result of superthermality (via) and also the physical parameters (ion temperature, soliton speed, electron-beam density and electron-beam velocity) are examined. A typical interaction between IASWs and the electron-beam in plasma is conf...
Nonlinear propagation of ion-acoustic waves in a degenerate dense plasma
Indian Academy of Sciences (India)
M M Masud; A A Mamun
2013-07-01
Nonlinear propagation of ion-acoustic (IA) waves in a degenerate dense plasma (with all the constituents being degenerate, for both the non-relativistic or ultrarelativistic cases) have been investigated by the reductive perturbation method. The linear dispersion relation and Korteweg de Vries (KdV) equation have been derived, and the numerical solutions of KdV equation have been analysed to identify the basic features of electrostatic solitary structures that may form in such a degenerate dense plasma. The implications of our results in compact astrophysical objects, particularly, in white dwarfs and neutron stars, have been briefly discussed.
Esfandyari-Kalejahi, Abdolrasoul; Saberian, Ehsan; 10.1585/pfr.5.045
2011-01-01
Arbitrary amplitude ion-acoustic solitary waves (IASWs) are studied using Sagdeev-Potential approach in electron-positron-ion plasma with ultra-relativistic or non-relativistic degenerate electrons and positrons and the matching criteria of existence of such solitary waves are numerically investigated. It has been shown that the relativistic degeneracy of electrons and positrons has significant effects on the amplitude and the Mach-number range of IASWs. Also it is remarked that only compressive IASWs can propagate in both non-relativistic and ultra-relativistic degenerate plasmas.
New Exact Solutions of Ion-Acoustic Wave Equations by (G′/G-Expansion Method
Directory of Open Access Journals (Sweden)
Wafaa M. Taha
2013-01-01
Full Text Available The (G′/G-expansion method is used to study ion-acoustic waves equations in plasma physic for the first time. Many new exact traveling wave solutions of the Schamel equation, Schamel-KdV (S-KdV, and the two-dimensional modified KP (Kadomtsev-Petviashvili equation with square root nonlinearity are constructed. The traveling wave solutions obtained via this method are expressed by hyperbolic functions, the trigonometric functions, and the rational functions. In addition to solitary waves solutions, a variety of special solutions like kink shaped, antikink shaped, and bell type solitary solutions are obtained when the choice of parameters is taken at special values. Two- and three-dimensional plots are drawn to illustrate the nature of solutions. Moreover, the solution obtained via this method is in good agreement with previously obtained solutions of other researchers.
Nonlinear ion acoustic waves scattered by vortexes
Ohno, Yuji
2015-01-01
The Kadomtsev--Petviashvili (KP) hierarchy is the archetype of infinite-dimensional integrable systems, which describes nonlinear ion acoustic waves in two-dimensional space. This remarkably ordered system resides on a singular submanifold (leaf) embedded in a larger phase space of more general ion acoustic waves (low-frequency electrostatic perturbations). The KP hierarchy is characterized not only by small amplitudes but also by irrotational (zero-vorticity) velocity fields. In fact, the KP equation is derived by eliminating vorticity at every order of the reductive perturbation. Here we modify the scaling of the velocity field so as to introduce a vortex term. The newly derived system of equations consists of a generalized three-dimensional KP equation and a two-dimensional vortex equation. The former describes `scattering' of vortex-free waves by ambient vortexes that are determined by the latter. We say that the vortexes are `ambient' because they do not receive reciprocal reactions from the waves (i.e.,...
Nonlinear ion acoustic waves scattered by vortexes
Ohno, Yuji; Yoshida, Zensho
2016-09-01
The Kadomtsev-Petviashvili (KP) hierarchy is the archetype of infinite-dimensional integrable systems, which describes nonlinear ion acoustic waves in two-dimensional space. This remarkably ordered system resides on a singular submanifold (leaf) embedded in a larger phase space of more general ion acoustic waves (low-frequency electrostatic perturbations). The KP hierarchy is characterized not only by small amplitudes but also by irrotational (zero-vorticity) velocity fields. In fact, the KP equation is derived by eliminating vorticity at every order of the reductive perturbation. Here, we modify the scaling of the velocity field so as to introduce a vortex term. The newly derived system of equations consists of a generalized three-dimensional KP equation and a two-dimensional vortex equation. The former describes 'scattering' of vortex-free waves by ambient vortexes that are determined by the latter. We say that the vortexes are 'ambient' because they do not receive reciprocal reactions from the waves (i.e., the vortex equation is independent of the wave fields). This model describes a minimal departure from the integrable KP system. By the Painlevé test, we delineate how the vorticity term violates integrability, bringing about an essential three-dimensionality to the solutions. By numerical simulation, we show how the solitons are scattered by vortexes and become chaotic.
Energy Technology Data Exchange (ETDEWEB)
Mamun, A.A. [Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Eliasson, B. [Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)]. E-mail: bengt@tp4.rub.de; Shukla, P.K. [Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)
2004-11-22
It is shown that the nonlinear propagation of dust-acoustic waves in a strongly coupled dusty plasma is governed by a modified Korteweg-de-Vries-Burgers (KdV-Burgers) equation. The latter is derived from a set of generalized hydrodynamic equations for strongly correlated dust grains in a liquid-like state, a Boltzmann electron distribution, and a non-isothermal vortex-like ion distribution. The numerical solutions of the modified KdV-Burgers equation are presented in order to provide some salient features of dust-acoustic solitary and shock structures that may exist in laboratory dusty plasmas where the dust grains are in a strongly coupled liquid phase.
Ion-acoustic solitons do not exist in cylindrical and spherical geometries
Sheridan, T. E.
2017-09-01
We investigate the time evolution of one-dimensional, compressive, ion acoustic solitary waves for planar, cylindrical, and spherical geometries in a plasma of cold fluid ions and Boltzmann electrons. For cylindrical and spherical geometries, we show that inward (outward) going solitary waves cannot be localized (i.e., always have a tail) since the effect of a unipolar velocity perturbation is to shift ions inward (outward) to smaller (larger) radii, thereby increasing (decreasing) the local ion density. That is, there are no quasi-particle soliton states in the cylindrical and spherical cases. These results are confirmed and expanded using a plasma simulation for the cylindrical case. We initialize the system with an inward propagating planar soliton. We find supersonic solitary waves which increase in speed as they near the origin, while the wave amplitude increases as r-1/2. All solitary waves develop the predicted tail, but for larger amplitudes, the tail is unstable and evolves into an acoustic wave train.
Directory of Open Access Journals (Sweden)
S. A. El-Wakil
2012-01-01
Full Text Available The reductive perturbation method has been employed to derive the Korteweg-de Vries (KdV equation for small- but finite-amplitude electrostatic ion-acoustic waves in weakly relativistic plasma consisting of warm ions and isothermal electrons. An algebraic method with computerized symbolic computation is applied in obtaining a series of exact solutions of the KdV equation. Numerical studies have been made using plasma parameters which reveal different solutions, that is, bell-shaped solitary pulses, rational pulses, and solutions with singularity at finite points, which called “blowup” solutions in addition to the propagation of an explosive pulses. The weakly relativistic effect is found to significantly change the basic properties (namely, the amplitude and the width of the ion-acoustic waves. The result of the present investigation may be applicable to some plasma environments, such as ionosphere region.
Solitary waves in dusty plasmas with weak relativistic effects in electrons and ions
Energy Technology Data Exchange (ETDEWEB)
Kalita, B. C., E-mail: bckalita123@gmail.com [Gauhati University, Department of Mathematics (India); Choudhury, M., E-mail: choudhurymamani@gmail.com [Handique Girls’ College, Department of Mathematics (India)
2016-10-15
Two distinct classes of dust ion acoustic (DIA) solitary waves based on relativistic ions and electrons, dust charge Z{sub d} and ion-to-dust mass ratio Q’ = m{sub i}/m{sub d} are established in this model of multicomponent plasmas. At the increase of mass ratio Q’ due to increase of relativistic ion mass and accumulation of more negative dust charges into the plasma causing decrease of dust mass, relativistic DIA solitons of negative potentials are abundantly observed. Of course, relativistic compressive DIA solitons are also found to exist simultaneously. Further, the decrease of temperature inherent in the speed of light c causes the nonlinear term to be more active that increases the amplitude of the rarefactive solitons and dampens the growth of compressive solitons for relatively low and high mass ratio Q’, respectively. The impact of higher initial streaming of the massive ions is observed to identify the point of maximum dust density N{sub d} to yield rarefactive relativistic solitons of maximum amplitude.
Ion-Acoustic Instabilities in a Multi-Ion Plasma
Directory of Open Access Journals (Sweden)
Noble P. Abraham
2013-01-01
Full Text Available We have, in this paper, studied the stability of the ion-acoustic wave in a plasma composed of hydrogen, positively and negatively charged oxygen ions, and electrons, which approximates very well the plasma environment around a comet. Modelling each cometary component (H+, O+, and O− by a ring distribution, we find that ion-acoustic waves can be generated at frequencies comparable to the hydrogen ion plasma frequency. The dispersion relation has been solved both analytically and numerically. We find that the ratio of the ring speed (u⊥s to the thermal spread (vts modifies the dispersion characteristics of the ion-acoustic wave. The contrasting behaviour of the phase velocity of the ion-acoustic wave in the presence of O− ions for u⊥s>vts (and vice versa can be used to detect the presence of negatively charged oxygen ions and also their thermalization.
Ion-acoustic cnoidal waves in a quantum plasma
Mahmood, Shahzad
2016-01-01
Nonlinear ion-acoustic cnoidal wave structures are studied in an unmagnetized quantum plasma. Using the reductive perturbation method, a Korteweg-de Vries equation is derived for appropriate boundary conditions and nonlinear periodic wave solutions are obtained. The corresponding analytical solution and numerical plots of the ion-acoustic cnoidal waves and solitons in the phase plane are presented using the Sagdeev pseudo-potential approach. The variations in the nonlinear potential of the ion-acoustic cnoidal waves are studied at different values of quantum parameter $H_{e}$ which is the ratio of electron plasmon energy to electron Fermi energy defined for degenerate electrons. It is found that both compressive and rarefactive ion-acoustic cnoidal wave structures are formed depending on the value of the quantum parameter. The dependence of the wavelength and frequency on nonlinear wave amplitude is also presented.
Non-Linear Excitation of Ion Acoustic Waves
DEFF Research Database (Denmark)
Michelsen, Poul; Hirsfield, J. L.
1974-01-01
The excitation of ion acoustic waves by nonlinear coupling of two transverse magnetic waves generated in a microwave cavity was investigated. Measurements of the wave amplitude showed good agreement with calculations based on the Vlasov equation.......The excitation of ion acoustic waves by nonlinear coupling of two transverse magnetic waves generated in a microwave cavity was investigated. Measurements of the wave amplitude showed good agreement with calculations based on the Vlasov equation....
Ion Acoustic Waves in the Presence of Electron Plasma Waves
DEFF Research Database (Denmark)
Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens
1977-01-01
Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave.......Long-wavelength ion acoustic waves in the presence of propagating short-wavelength electron plasma waves are examined. The influence of the high frequency oscillations is to decrease the phase velocity and the damping distance of the ion wave....
Linear and nonlinear heavy ion-acoustic waves in a strongly coupled plasma
Energy Technology Data Exchange (ETDEWEB)
Ema, S. A., E-mail: ema.plasma@gmail.com; Mamun, A. A. [Department of Physics, Jahangirnagar University, Savar, Dhaka-1342 (Bangladesh); Hossen, M. R. [Deparment of Natural Sciences, Daffodil International University, Sukrabad, Dhaka-1207 (Bangladesh)
2015-09-15
A theoretical study on the propagation of linear and nonlinear heavy ion-acoustic (HIA) waves in an unmagnetized, collisionless, strongly coupled plasma system has been carried out. The plasma system is assumed to contain adiabatic positively charged inertial heavy ion fluids, nonextensive distributed electrons, and Maxwellian light ions. The normal mode analysis is used to study the linear behaviour. On the other hand, the well-known reductive perturbation technique is used to derive the nonlinear dynamical equations, namely, Burgers equation and Korteweg-de Vries (K-dV) equation. They are also numerically analyzed in order to investigate the basic features of shock and solitary waves. The adiabatic effects on the HIA shock and solitary waves propagating in such a strongly coupled plasma are taken into account. It has been observed that the roles of the adiabatic positively charged heavy ions, nonextensivity of electrons, and other plasma parameters arised in this investigation have significantly modified the basic features (viz., polarity, amplitude, width, etc.) of the HIA solitary/shock waves. The findings of our results obtained from this theoretical investigation may be useful in understanding the linear as well as nonlinear phenomena associated with the HIA waves both in space and laboratory plasmas.
Kinetic treatment of nonlinear ion-acoustic waves in multi-ion plasma
Ahmad, Zulfiqar; Ahmad, Mushtaq; Qamar, A.
2017-09-01
By applying the kinetic theory of the Valsove-Poisson model and the reductive perturbation technique, a Korteweg-de Vries (KdV) equation is derived for small but finite amplitude ion acoustic waves in multi-ion plasma composed of positive and negative ions along with the fraction of electrons. A correspondent equation is also derived from the basic set of fluid equations of adiabatic ions and isothermal electrons. Both kinetic and fluid KdV equations are stationary solved with different nature of coefficients. Their differences are discussed both analytically and numerically. The criteria of the fluid approach as a limiting case of kinetic theory are also discussed. The presence of negative ion makes some modification in the solitary structure that has also been discussed with its implication at the laboratory level.
Energy Technology Data Exchange (ETDEWEB)
Rufai, O. R., E-mail: rajirufai@gmail.com; Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Belville (South Africa); Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai (India)
2014-08-15
Arbitrary amplitude, ion acoustic solitons, and supersolitons are studied in a magnetized plasma with two distinct groups of electrons at different temperatures. The plasma consists of a cold ion fluid, cool Boltzmann electrons, and nonthermal energetic hot electrons. Using the Sagdeev pseudo-potential technique, the effect of nonthermal hot electrons on soliton structures with other plasma parameters is studied. Our numerical computation shows that negative potential ion-acoustic solitons and double layers can exist both in the subsonic and supersonic Mach number regimes, unlike the case of an unmagnetized plasma where they can only exist in the supersonic Mach number regime. For the first time, it is reported here that in addition to solitions and double layers, the ion-acoustic supersoliton solutions are also obtained for certain range of parameters in a magnetized three-component plasma model. The results show good agreement with Viking satellite observations of the solitary structures with density depletions in the auroral region of the Earth's magnetosphere.
Energy Technology Data Exchange (ETDEWEB)
Saha, Asit, E-mail: asit-saha123@rediffmail.com, E-mail: prasantachatterjee1@rediffmail.com [Department of Mathematics, Sikkim Manipal Institute of Technology, Majitar, Rangpo, East-Sikkim 737136 (India); Department of Mathematics, Siksha Bhavana, Visva Bharati University, Santiniketan-731235 (India); Pal, Nikhil; Chatterjee, Prasanta, E-mail: asit-saha123@rediffmail.com, E-mail: prasantachatterjee1@rediffmail.com [Department of Mathematics, Siksha Bhavana, Visva Bharati University, Santiniketan-731235 (India)
2014-10-15
The dynamic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas with superthermal electrons and positrons has been investigated in the framework of perturbed and non-perturbed Kadomtsev-Petviashili (KP) equations. Applying the reductive perturbation technique, we have derived the KP equation in electron-positron-ion magnetoplasma with kappa distributed electrons and positrons. Bifurcations of ion acoustic traveling waves of the KP equation are presented. Using the bifurcation theory of planar dynamical systems, the existence of the solitary wave solutions and the periodic traveling wave solutions has been established. Two exact solutions of these waves have been derived depending on the system parameters. Then, using the Hirota's direct method, we have obtained two-soliton and three-soliton solutions of the KP equation. The effect of the spectral index κ on propagations of the two-soliton and the three-soliton has been shown. Considering an external periodic perturbation, we have presented the quasi periodic behavior of ion acoustic waves in electron-positron-ion magnetoplasmas.
Effect of viscosity on dust–ion acoustic shock wave in dusty plasma with negative ions
Energy Technology Data Exchange (ETDEWEB)
Adhikary, Nirab C., E-mail: nirab_iasst@yahoo.co.in [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Garchuk, Guwahati 781035, Assam (India)
2012-03-26
The properties of dust–ion acoustic (DIA) shock wave in a dusty plasma containing positive and negative ions is investigated. The reductive perturbation method has been used to derive the Korteweg–de Vries–Burgers equation for dust acoustic shock waves in a homogeneous, unmagnetized and collisionless plasma whose constituents are Boltzmann distributed electrons, singly charged positive ions, singly charged negative ions and cold static dust particles. The KdV–Burgers equation is derived and its stationary analytical solution is numerically analyzed where the effect of viscosity on the DIA shock wave propagation is taken into account. It is found that the viscosity in the dusty plasma plays as a key role in dissipation for the propagation of DIA shock. -- Highlights: ► Dust–ion acoustic shock wave propagation is studied in multi-component dusty plasma. ► KdV–Burgers equation is derived and its stationary solution is numerically analyzed. ► Viscosity in dusty plasma plays as a key role in dissipation of DIA shock wave.
Naturally enhanced ion-acoustic lines at high altitudes
Directory of Open Access Journals (Sweden)
Y. Ogawa
2006-12-01
Full Text Available Naturally enhanced ion-acoustic lines (NEIALs between 1200 and 1900 km altitude are investigated. The NEIALs were found in the background gates of data from the European Incoherent Scatter (EISCAT Svalbard radar (ESR at 78° N looking field-aligned. Only strongly enhanced lines are detected at such high altitudes. The estimated enhancement above incoherent scattering integrated over the antenna beam and preintegration time of 10 s reaches about 10 000. Both lines are always enhanced above 1000 km altitude, and the downshifted line, corresponding to upward propagating ion-acoustic waves, is always stronger than the upshifted line, for downgoing waves. The ratio of the downshifted and upshifted peaks is often remarkably constant along a profile. Using the line positions as indicators of the ion-acoustic speeds and the bulk drift velocity, we find that the bulk drift does not exceed the ion-acoustic (sound speed, but extrapolation of the profiles suggests that the sound barrier is reached around 2000 km in one event. The highest ion-acoustic speed is seen near 600 km, above the density peak, indicating that electrons are heated not only by ionizing precipitation but significantly also by upgoing waves. Upflow continues to speed up above the estimated temperature maximum. A certain qualitative similarity to the solar corona seems to be the case.
Nonlinear features of ion acoustic shock waves in dissipative magnetized dusty plasma
Sahu, Biswajit; Sinha, Anjana; Roychoudhury, Rajkumar
2014-10-01
The nonlinear propagation of small as well as arbitrary amplitude shocks is investigated in a magnetized dusty plasma consisting of inertia-less Boltzmann distributed electrons, inertial viscous cold ions, and stationary dust grains without dust-charge fluctuations. The effects of dissipation due to viscosity of ions and external magnetic field, on the properties of ion acoustic shock structure, are investigated. It is found that for small amplitude waves, the Korteweg-de Vries-Burgers (KdVB) equation, derived using Reductive Perturbation Method, gives a qualitative behaviour of the transition from oscillatory wave to shock structure. The exact numerical solution for arbitrary amplitude wave differs somehow in the details from the results obtained from KdVB equation. However, the qualitative nature of the two solutions is similar in the sense that a gradual transition from KdV oscillation to shock structure is observed with the increase of the dissipative parameter.
Nonlinear features of ion acoustic shock waves in dissipative magnetized dusty plasma
Energy Technology Data Exchange (ETDEWEB)
Sahu, Biswajit, E-mail: biswajit-sahu@yahoo.co.in [Department of Mathematics, West Bengal State University, Barasat, Kolkata 700126 (India); Sinha, Anjana, E-mail: sinha.anjana@gmail.com [Department of Instrumentation Science, Jadavpur University, Kolkata 700032 (India); Roychoudhury, Rajkumar, E-mail: rroychoudhury123@gmail.com [Department of Mathematics, Visva-Bharati, Santiniketan 731204, India and Advanced Centre for Nonlinear and Complex Phenomena, 1175 Survey Park, Kolkata 700075 (India)
2014-10-15
The nonlinear propagation of small as well as arbitrary amplitude shocks is investigated in a magnetized dusty plasma consisting of inertia-less Boltzmann distributed electrons, inertial viscous cold ions, and stationary dust grains without dust-charge fluctuations. The effects of dissipation due to viscosity of ions and external magnetic field, on the properties of ion acoustic shock structure, are investigated. It is found that for small amplitude waves, the Korteweg-de Vries-Burgers (KdVB) equation, derived using Reductive Perturbation Method, gives a qualitative behaviour of the transition from oscillatory wave to shock structure. The exact numerical solution for arbitrary amplitude wave differs somehow in the details from the results obtained from KdVB equation. However, the qualitative nature of the two solutions is similar in the sense that a gradual transition from KdV oscillation to shock structure is observed with the increase of the dissipative parameter.
Ion acoustic shocks in magneto rotating Lorentzian plasmas
Energy Technology Data Exchange (ETDEWEB)
Hussain, S.; Akhtar, N. [Theoretical Physics Division, PINSTECH, NILORE, Islamabad 44000 (Pakistan); DPAM, PIEAS, NILORE, Islamabad 44000 (Pakistan); Hasnain, H. [Theoretical Physics Division, PINSTECH, NILORE, Islamabad 44000 (Pakistan)
2014-12-15
Ion acoustic shock structures in magnetized homogeneous dissipative Lorentzian plasma under the effects of Coriolis force are investigated. The dissipation in the plasma system is introduced via dynamic viscosity of inertial ions. The electrons are following the kappa distribution function. Korteweg-de Vries Burger (KdVB) equation is derived by using reductive perturbation technique. It is shown that spectral index, magnetic field, kinematic viscosity of ions, rotational frequency, and effective frequency have significant impact on the propagation characteristic of ion acoustic shocks in such plasma system. The numerical solution of KdVB equation is also discussed and transition from oscillatory profile to monotonic shock for different plasma parameters is investigated.
Kinetic study of ion-acoustic plasma vortices
Energy Technology Data Exchange (ETDEWEB)
Khan, S. A. [National Centre for Physics (NCP), Quaid-i-Azam University Campus, Islamabad 45320 (Pakistan); Aman-ur-Rehman, E-mail: amansadiq@gmail.com [Pakistan Institute of Engineering and Applied Sciences (PIEAS), P.O. Nilore, Islamabad 45650 (Pakistan); Mendonca, J. T. [IPFN, Instituto Superior Téchnico, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)
2014-09-15
The kinetic theory of electron plasma waves with finite orbital angular momentum has recently been introduced by Mendonca. This model shows possibility of new kind of plasma waves and instabilities. We have extended the theory to ion-acoustic plasma vortices carrying orbital angular momentum. The dispersion equation is derived under paraxial approximation which exhibits a kind of linear vortices and their Landau damping. The numerical solutions are obtained and compared with analytical results which are in good agreement. The physical interpretation of the ion-acoustic plasma vortices and their Landau resonance conditions are given for typical case of Maxwellian plasmas.
Energy Technology Data Exchange (ETDEWEB)
Kakad, Amar [Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011 (Japan); Indian Institute of Geomagnetism, New Panvel, Navi Mumbai 410-218 (India); Omura, Yoshiharu [Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto 611-0011 (Japan); Kakad, Bharati [Indian Institute of Geomagnetism, New Panvel, Navi Mumbai 410-218 (India)
2013-06-15
We perform one-dimensional fluid simulation of ion acoustic (IA) solitons propagating parallel to the magnetic field in electron-ion plasmas by assuming a large system length. To model the initial density perturbations (IDP), we employ a KdV soliton type solution. Our simulation demonstrates that the generation mechanism of IA solitons depends on the wavelength of the IDP. The short wavelength IDP evolve into two oppositely propagating identical IA solitons, whereas the long wavelength IDP develop into two indistinguishable chains of multiple IA solitons through a wave breaking process. The wave breaking occurs close to the time when electrostatic energy exceeds half of the kinetic energy of the electron fluid. The wave breaking amplitude and time of its initiation are found to be dependent on characteristics of the IDP. The strength of the IDP controls the number of IA solitons in the solitary chains. The speed, width, and amplitude of IA solitons estimated during their stable propagation in the simulation are in good agreement with the nonlinear fluid theory. This fluid simulation is the first to confirm the validity of the general nonlinear fluid theory, which is widely used in the study of solitary waves in laboratory and space plasmas.
Dynamic rayed aurora and enhanced ion-acoustic radar echoes
Directory of Open Access Journals (Sweden)
E. M. Blixt
2005-01-01
Full Text Available The generation mechanism for naturally enhanced ion-acoustic echoes is still debated. One important issue is how these enhancements are related to auroral activity. All events of enhanced ion-acoustic echoes observed simultaneously with the EISCAT Svalbard Radar (ESR and with high-resolution narrow field-of-view auroral imagers have been collected and studied. Characteristic of all the events is the appearance of very dynamic rayed aurora, and some of the intrinsic features of these auroral displays are identified. Several of these identified features are directly related to the presence of low energy (10-100eV precipitating electrons in addition to the higher energy population producing most of the associated light. The low energy contribution is vital for the formation of the enhanced ion-acoustic echoes. We argue that this type of aurora is sufficient for the generation of naturally enhanced ion-acoustic echoes. In one event two imagers were used to observe the auroral rays simultaneously, one from the radar site and one 7km away. The data from these imagers shows that the auroral rays and the strong backscattering filaments (where the enhanced echoes are produced are located on the same field line, which is in contrast to earlier statements in the litterature that they should be separated.
Ion Acoustic Waves in the Presence of Langmuir Oscillations
DEFF Research Database (Denmark)
Pécseli, Hans
1976-01-01
The dielectric function for long-wavelength, low-frequency ion acoustic waves in the presence of short-wavelength, high-frequency electron oscillations is presented, where the ions are described by the collision-free Vlasov equation. The effect of the electron oscillations can be appropriately...
Large amplitude ion-acoustic double layers in warm dusty plasma
Jain, S. L.; Tiwari, R. S.; Mishra, M. K.
2015-01-01
Large amplitude ion-acoustic double layer (IADL) is studied using Sagdeev's pseudo-potential technique in collisionless unmagnetized plasma comprising hot and cold Maxwellian population of electrons, warm adiabatic ions, and dust grains. Variation of both Mach number (M) and amplitude |φ m | of large amplitude IADL with charge, concentration, and mass of heavily charged massive dust grains is investigated for both positive and negative dust in plasma. Our numerical analysis shows that system supports only rarefactive large amplitude IADL for the selected set of plasma parameters. Our investigations for both negative and positive dust grains reveal that ion temperature increases the mobility of ions, resulting in increase in the Mach number of IADL. The larger mobility of ions causes leakage of ions from localized region, resulting into decrease in the amplitude of IADL. Other parameters, e.g. temperature ratio of hot to cold electrons, charge, concentration, mass of heavily charged massive dust grains also play significant role in the properties and existence of double layers. Since it is well established that both positive and negative dust are found in space as well as laboratory plasma, and double layers have a tremendous role to play in astrophysics, we have included both positive and negative dust in our numerical analysis for the study of large amplitude IADL. Further data used for negative dust are close to experimentally observed data. Hence, it is anticipated that our parametric studies for heavily charged (both positive and negative) dust may be useful in understanding laboratory plasma experiments, identifying nonlinear structures in upper part of ionosphere and lower part of magnetosphere structures, and in theoretical research for the study of properties of nonlinear structures.
Energy Technology Data Exchange (ETDEWEB)
Roy Chowdhury, K. [Department of Physics, J.C.C. College, Kolkata 700 033 (India); Mishra, Amar P. [High Energy Physics Division, Department of Physics Jadavpur University, Kolkata 700 032 (India); Roy Chowdhury, A. [High Energy Physics Division, Department of Physics Jadavpur University, Kolkata 700 032 (India)
2006-07-15
A modified KdV equation is derived for the propagation of non-linear waves in a dusty plasma, containing N different dust grains with a size distribution and charge fluctuation with electrons in the background. The ions are assumed to obey a vortex like distribution due to their non-isothermal nature. The standard distribution for the dust size is a power law. The variation of the soliton width is studied with respect to normalized size of the dust grains. A numerical solution of the equation is done by considering the soliton solution of the modified KdV as the initial pulse. It shows considerable broadening of the pulse variation of width with {beta} {sub 1} is shown.
Drift and ion acoustic wave driven vortices with superthermal electrons
Energy Technology Data Exchange (ETDEWEB)
Ali Shan, S. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); National Centre For Physics (NCP), Shahdra Valley Road, QAU Campus, 44000 Islamabad (Pakistan); Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad (Pakistan); Haque, Q. [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); National Centre For Physics (NCP), Shahdra Valley Road, QAU Campus, 44000 Islamabad (Pakistan)
2012-08-15
Linear and nonlinear analysis of coupled drift and acoustic mode is presented in an inhomogeneous electron-ion plasma with {kappa}-distributed electrons. A linear dispersion relation is found which shows that the phase speed of both the drift wave and the ion acoustic wave decreases in the presence of superthermal electrons. Several limiting cases are also discussed. In the nonlinear regime, stationary solutions in the form of dipolar and monopolar vortices are obtained. It is shown that the condition for the boundedness of the solution implies that the speed of drift wave driven vortices reduces with increase in superthermality effect. Ignoring density inhomogeniety, it is investigated that the lower and upper limits on the speed of the ion acoustic driven vortices spread with the inclusion of high energy electrons. The importance of results with reference to space plasmas is also pointed out.
Anomalous absorption of laser light on ion acoustic fluctuations
Rozmus, Wojciech; Bychenkov, Valery Yu.
2016-10-01
Theory of laser light absorption due to ion acoustic turbulence (IAT) is discussed in high Z plasmas where ion acoustic waves are weakly damped. Our theory applies to the whole density range from underdense to critical density plasmas. It includes an absorption rate for the resonance anomalous absorption due to linear conversion of electromagnetic waves into electron plasma oscillations by the IAT near the critical density in addition to the absorption coefficient due to enhanced effective electron collisionality. IAT is driven by large electron heat flux through the return current instability. Stationary spectra of IAT are given by weak plasma turbulence theory and applied in description of the anomalous absorption in the inertial confinement fusion plasmas at the gold walls of a hohlraum. This absorption is anisotropic in nature due to IAT angular anisotropy and differs for p- and s-polarization of the laser radiation. Possible experiments which could identify the resonance anomalous absorption in a laser heated plasma are discussed.
Jain, S. L.; Tiwari, R. S.; Mishra, M. K.
2015-05-01
Large amplitude ion-acoustic solitons and double layers are studied using Sagdeev's pseudo potential technique in a collisionless unmagnetized plasma consisting of hot and cold Maxwellian electrons, warm adiabatic ions, and heavily charged massive dust grains. It is found that for the selected set of plasma parameters, the system can support both solitons and double layers in the presence of negative as well as positive dust in the plasma. Further we have also investigated the ranges of parameters for simultaneous existence of both rarefactive and compressive supersonic solitons. The effects of dust concentration and ion temperature on the amplitude and Mach number of the double layer have also been studied. Our findings may be helpful in understanding the formation of non-linear structures, specially the solitons and double layers in space plasma, such as: in interstellar clouds, circumstellar clouds, planetary rings, comets, cometary tails, asteroid zones, auroral plasma, magnetospheric plasma, pulsars, and other astronomical environments and laboratory plasmas.
Lotekar, Ajay; Kakad, Amar; Kakad, Bharati
2016-10-01
One-dimensional fluid simulation is performed for the unmagnetized plasma consisting of cold fluid ions and superthermal electrons. Such a plasma system supports the generation of ion acoustic (IA) waves. A standard Gaussian type perturbation is used in both electron and ion equilibrium densities to excite the IA waves. The evolutionary profiles of the IA waves are obtained by varying the superthermal index and the amplitude of the initial perturbation. This simulation demonstrates that the amplitude of the initial perturbation and the superthermal index play an important role in determining the time evolution and the characteristics of the generated IA waves. The initial density perturbation in the system creates charge separation that drives the finite electrostatic potential in the system. This electrostatic potential later evolves into the dispersive and nondispersive IA waves in the simulation system. The density perturbation with the amplitude smaller than 10% of the equilibrium plasma density evolves into the dispersive IA waves, whereas larger density perturbations evolve into both dispersive and nondispersive IA waves for lower and higher superthermal index. The dispersive IA waves are the IA oscillations that propagate with constant ion plasma frequency, whereas the nondispersive IA waves are the IA solitary pulses (termed as IA solitons in the stability region) that propagate with the constant wave speed. The characteristics of the stable nondispersive IA solitons are found to be consistent with the nonlinear fluid theory. To the best of our knowledge, this is the first fluid simulation study that has considered the superthermal distributions for the plasma species to model the electrostatic solitary waves.
Ion-acoustic Gardner solitons in a four-component nonextensive multi-ion plasma
Jannat, N.; Ferdousi, M.; Mamun, A. A.
2016-07-01
The nonlinear propagation of ion-acoustic (IA) solitary waves (SWs) in a four-component non-extensive multi-ion plasma system containing inertial positively charged light ions, negatively charged heavy ions, as well as noninertial nonextensive electrons and positrons has been theoretically investigated. The reductive perturbation method has been employed to derive the nonlinear equations, namely, Korteweg-deVries (KdV), modified KdV (mKdV), and Gardner equations. The basic features (viz. polarity, amplitude, width, etc.) of Gardner solitons are found to exist beyond the KdV limit and these IA Gardner solitons are qualitatively different from the KdV and mKdV solitons. It is observed that the basic features of IA SWs are modified by various plasma parameters (viz. electron and positron nonextensivity, electron number density to ion number density, and electron temperature to positron temperature, etc.) of the considered plasma system. The results obtained from this theoretical investigation may be useful in understanding the basic features of IA SWs propagating in both space and laboratory plasmas.
Effect of Bohm quantum potential in the propagation of ion-acoustic waves in degenerate plasmas
Hasan, M. M.; Hossen, M. A.; Rafat, A.; Mamun, A. A.
2016-10-01
A theoretical investigation has been carried out on the propagation of the ion-acoustic (IA) waves in a relativistic degenerate plasma containing relativistic degenerate electron and positron fluids in the presence of inertial non-relativistic light ion fluid. The Korteweg-de Vries (K-dV), modified K-dV (mK-dV), and mixed mK-dV (mmK-dV) equations are derived by adopting the reductive perturbation method. In order to analyze the basic features (phase speed, amplitude, width, etc.) of the IA solitary waves (SWs), the SWs solutions of the K-dV, mK-dV, and mmK-dV are numerically analyzed. It is found that the degenerate pressure, inclusion of the new phenomena like the Fermi temperatures and quantum mechanical effects (arising due to the quantum diffraction) of both electrons and positrons, number densities, etc., of the plasma species remarkably change the basic characteristics of the IA SWs which are found to be formed either with positive or negative potential. The implication of our results in explaining different nonlinear phenomena in astrophysical compact objects, e.g., white dwarfs, neutron stars, etc., and laboratory plasmas like intense laser-solid matter interaction experiments, etc., are mentioned.
Modulational instability of ion-acoustic waves in a warm plasma
Institute of Scientific and Technical Information of China (English)
薛具奎; 段文山; 郎和
2002-01-01
Using the standard reductive perturbation technique, a nonlinear Schrodinger equation is derived to study themodulational instability of finite-amplitude ion-acoustic waves in a non-magnetized warm plasma. It is found thatthe inclusion of ion temperature in the equation modifies the nature of the ion-acoustic wave stability and the solitonstructures. The effects of ion plasma temperature on the modulational stability and ion-acoustic wave properties areinvestigated in detail.
Ion-acoustic solitons in multispecies spatially inhomogeneous plasmas
Indian Academy of Sciences (India)
Tarsem Singh Gill; Harvinder Kaur; Nareshpal Singh Saini
2006-06-01
Ion-acoustic solitons are investigated in the spatially inhomogeneous plasma having electrons-positrons and ions. The soliton characteristics are described by Korteweg-de Vries equation which has an additional term. The density and temperature of different species play an important role for the amplitude and width of the solitons. Numerical calculations show only the possibility of compressive solitons. Further, analytical results predict that the peak amplitude of soliton decreases with the decrease of density gradient. Soliton characteristics like peak amplitude and width are substantially different from those based on KdV theory for homogeneous plasmas.
Investigation of Ion Acoustic Waves in Collisionless Plasmas
DEFF Research Database (Denmark)
Christoffersen, G. B.; Jensen, Vagn Orla; Michelsen, Poul
1974-01-01
The Green's functions for the linearized ion Vlasov equation with a given boundary value are derived. The propagation properties of ion acoustic waves are calculated by performing convolution integrals over the Green's functions. For Te/Ti less than about 3 it is concluded that the collective...... interaction is very weak and that the propagation properties are determined almost completely by freely streaming ions. The wave damping, being due to phase mixing, is determined by the width of the perturbed distribution function rather than by the slope of the undisturbed distribution function at the phase...
Damping-Growth Transition for Ion-Acoustic Waves in a Density Gradient
DEFF Research Database (Denmark)
D'Angelo, N.; Michelsen, Poul; Pécseli, Hans
1975-01-01
A damping-growth transition for ion-acoustic waves propagating in a nonuniform plasma (e-folding length for the density ln) is observed at a wavelength λ∼2πln. This result supports calculations performed in connection with the problem of heating of the solar corona by ion-acoustic waves generated...
Existence domains of slow and fast ion-acoustic solitons in two-ion space plasmas
Energy Technology Data Exchange (ETDEWEB)
Maharaj, S. K., E-mail: smaharaj@sansa.org.za [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200 (South Africa); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Robert Sobukwe Road, Bellville, 7535 (South Africa); Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India)
2015-03-15
A study of large amplitude ion-acoustic solitons is conducted for a model composed of cool and hot ions and cool and hot electrons. Using the Sagdeev pseudo-potential formalism, the scope of earlier studies is extended to consider why upper Mach number limitations arise for slow and fast ion-acoustic solitons. Treating all plasma constituents as adiabatic fluids, slow ion-acoustic solitons are limited in the order of increasing cool ion concentrations by the number densities of the cool, and then the hot ions becoming complex valued, followed by positive and then negative potential double layer regions. Only positive potentials are found for fast ion-acoustic solitons which are limited only by the hot ion number density having to remain real valued. The effect of neglecting as opposed to including inertial effects of the hot electrons is found to induce only minor quantitative changes in the existence regions of slow and fast ion-acoustic solitons.
Propagation of dust-acoustic waves in weakly ionized plasmas with dust-charge fluctuation
Indian Academy of Sciences (India)
K K Mondal
2004-11-01
For an unmagnetized partially ionized dusty plasma containing electrons, singly charged positive ions, micron-sized massive negatively charged dust grains and a fraction of neutral atoms, dispersion relations for both the dust-ion-acoustic and the dust-acoustic waves have been derived, incorporating dust charge fluctuation. The dispersion relations, under various conditions, have been exhaustively analysed. The explicit expressions for the growth rates have also been derived.
Electrostatic Korteweg-deVries solitary waves in a plasma with Kappa-distributed electrons
Energy Technology Data Exchange (ETDEWEB)
Choi, C.-R.; Min, K.-W. [Department of Physics, Korea Advanced Institute of Science and Technology, Taejon 305-701 (Korea, Republic of); Rhee, T.-N. [National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of)
2011-09-15
The Korteweg-deVries (KdV) equation that describes the evolution of nonlinear ion-acoustic solitary waves in plasmas with Kappa-distributed electrons is derived by using a reductive perturbation method in the small amplitude limit. We identified a dip-type (negative) electrostatic KdV solitary wave, in addition to the hump-type solution reported previously. The two types of solitary waves occupy different domains on the {kappa} (Kappa index)-V (propagation velocity) plane, separated by a curve corresponding to singular solutions with infinite amplitudes. For a given Kappa value, the dip-type solitary wave propagates faster than the hump-type. It was also found that the hump-type solitary waves cannot propagate faster than V = 1.32.
Planar dust-acoustic waves in electron-positron-ion-dust plasmas with dust size distribution
Energy Technology Data Exchange (ETDEWEB)
Wang, Hong-Yan; Zhang, Kai-Biao [Sichuan University of Science and Engineering, Zigong (China)
2014-06-15
Nonlinear dust-acoustic solitary waves which are described with a Kortweg-de vries (KdV) equation by using the reductive perturbation method, are investigated in a planar unmagnetized dusty plasma consisting of electrons, positrons, ions and negatively-charged dust particles of different sizes and masses. The effects of the power-law distribution of dust and other plasma parameters on the dust-acoustic solitary waves are studied. Numerical results show that the dust size distribution has a significant influence on the propagation properties of dust-acoustic solitons. The amplitudes of solitary waves in the case of a power-law distribution is observed to be smaller, but the soliton velocity and width are observed to be larger, than those of mono-sized dust grains with an average dust size. Our results indicate that only compressed solitary waves exist in dusty plasma with different dust species. The relevance of the present investigation to interstellar clouds is discussed.
Conditions for the Observation of Two Ion-Acoustic Waves via Thomson Scattering
Institute of Scientific and Technical Information of China (English)
郑坚; 胡广月; 王哲斌; 俞昌旋; 刘万东
2003-01-01
Observation of two ion-acoustic waves via Thomson scattering can provide precise measurements of plasma parameters. The conditions for the observation of two ion-acoustic modes in a two-ion plasmaare discussed.The ratio of electron temperature Te to ion temperature Ti is the critical parameter for the presence of two ion-acoustic modes, which should be in the range of 4/ZL(＜～)Te/Ti(＜～)2AH/ZHAL, where ZL,H are the charge states of light and heavy ions, and AL,H are the atomic numbers of light and heavy ions, respectively. As the temperature ratio varies in this range, the concentration of heavy ions must increase with the ratio Te/Ti so that the two ion-acoustic modes can have the same fluctuation levels.
Filamentation instability of nonextensive current-driven plasma in the ion acoustic frequency range
Energy Technology Data Exchange (ETDEWEB)
Khorashadizadeh, S. M., E-mail: smkhorashadi@birjand.ac.ir; Rastbood, E. [Physics Department of Birjand University, Birjand (Iran, Islamic Republic of); Niknam, A. R., E-mail: a-niknam@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)
2014-12-15
The filamentation and ion acoustic instabilities of nonextensive current-driven plasma in the ion acoustic frequency range have been studied using the Lorentz transformation formulas. Based on the kinetic theory, the possibility of filamentation instability and its growth rate as well as the ion acoustic instability have been investigated. The results of the research show that the possibility and growth rate of these instabilities are significantly dependent on the electron nonextensive parameter and drift velocity. Besides, the increase of electrons nonextensive parameter and drift velocity lead to the increase of the growth rates of both instabilities. In addition, the wavelength region in which the filamentation instability occurs is more stretched in the presence of higher values of drift velocity and nonextensive parameter. Finally, the results of filamentation and ion acoustic instabilities have been compared and the conditions for filamentation instability to be dominant mode of instability have been presented.
Kinetic study of ion acoustic twisted waves with kappa distributed electrons
Arshad, Kashif; Aman-ur-Rehman, Mahmood, Shahzad
2016-05-01
The kinetic theory of Landau damping of ion acoustic twisted modes is developed in the presence of orbital angular momentum of the helical (twisted) electric field in plasmas with kappa distributed electrons and Maxwellian ions. The perturbed distribution function and helical electric field are considered to be decomposed by Laguerre-Gaussian mode function defined in cylindrical geometry. The Vlasov-Poisson equation is obtained and solved analytically to obtain the weak damping rates of the ion acoustic twisted waves in a non-thermal plasma. The strong damping effects of ion acoustic twisted waves at low values of temperature ratio of electrons and ions are also obtained by using exact numerical method and illustrated graphically, where the weak damping wave theory fails to explain the phenomenon properly. The obtained results of Landau damping rates of the twisted ion acoustic wave are discussed at different values of azimuthal wave number and non-thermal parameter kappa for electrons.
Indian Academy of Sciences (India)
HARVINDER KAUR; TARSEM SINGH GILL; PARVEEN BALA
2017-08-01
In the present investigation, ion-acoustic double layers in an inhomogeneous plasma consisting of Maxwellian and non-thermal distributions of electrons are studied.We have derived a modified Korteweg–de Vries (mKdV) equation for ion-acoustic double layers propagating in a collisionless inhomogeneous plasma. It is observed that the non-thermal parameters affect the amplitude and width of the double layer which further depend on the density.
Excitation of nonlinear ion acoustic waves in CH plasmas
Feng, Q S; Liu, Z J; Xiao, C Z; Wang, Q; He, X T
2016-01-01
Excitation of nonlinear ion acoustic wave (IAW) by an external electric field is demonstrated by Vlasov simulation. The frequency calculated by the dispersion relation with no damping is verified much closer to the resonance frequency of the small-amplitude nonlinear IAW than that calculated by the linear dispersion relation. When the wave number $ k\\lambda_{De} $ increases, the linear Landau damping of the fast mode (its phase velocity is greater than any ion's thermal velocity) increases obviously in the region of $ T_i/T_e < 0.2 $ in which the fast mode is weakly damped mode. As a result, the deviation between the frequency calculated by the linear dispersion relation and that by the dispersion relation with no damping becomes larger with $k\\lambda_{De}$ increasing. When $k\\lambda_{De}$ is not large, such as $k\\lambda_{De}=0.1, 0.3, 0.5$, the nonlinear IAW can be excited by the driver with the linear frequency of the modes. However, when $k\\lambda_{De}$ is large, such as $k\\lambda_{De}=0.7$, the linear ...
Kaur, Nimardeep; Singh, Kuldeep; Saini, N. S.
2017-09-01
The nonlinear propagation of ion acoustic solitary waves (IASWs) is investigated in an unmagnetized plasma composed of a positive warm ion fluid, two temperature electrons obeying kappa type distribution and penetrated by a positive ion beam. The reductive perturbation method is used to derive the nonlinear equations, namely, Korteweg-de Vries (KdV), modified KdV (mKdV), and Gardner equations. The characteristic features of both compressive and rarefactive nonlinear excitations from the solution of these equations are studied and compared in the context with the observation of the He+ beam in the polar cap region near solar maximum by the Dynamics Explorer 1 satellite. It is observed that the superthermality and density of cold electrons, number density, and temperature of the positive ion beam crucially modify the basic properties of compressive and rarefactive IASWs in the KdV and mKdV regimes. It is further analyzed that the amplitude and width of Gardner solitons are appreciably affected by different plasma parameters. The characteristics of double layers are also studied in detail below the critical density of cold electrons. The theoretical results may be useful for the observation of nonlinear excitations in laboratory and ion beam driven plasmas in the polar cap region near solar maximum and polar ionosphere as well in Saturn's magnetosphere, solar wind, pulsar magnetosphere, etc., where the population of two temperature superthermal electrons is present.
Indian Academy of Sciences (India)
M Singh; P N Deka
2006-03-01
A theoretical study is made on the generation mechanism of ion acoustics wave in the presence of lower hybrid wave turbulence field in inhomogeneous plasma on the basis of plasma-maser interaction. The lower hybrid wave turbulence field is taken as the low-frequency turbulence field. The growth rate of test high frequency ion acoustics wave is obtained with the involvement of spatial density gradient parameter. A comparative study of the role of density gradient for the generation of ion acoustics wave on the basis of plasma-maser effect is presented. It is found that the density gradient influences the growth rate of ion acoustics wave.
Damping of an ion acoustic surface wave due to surface currents
Lee, H J
1999-01-01
The well-known linear dispersion relation for an ion acoustic surface wave has been obtained by including the linear surface current density J sub z parallel to the interface and by neglecting the linear surface current density J sub x perpendicular to the interface. The neglect of J sub x is questionable although it leads to the popular boundary condition that the tangential electric field is continuous. In this work, linear dispersion relation for an ion acoustic surface wave is worked out by including both components of the linear current density J . When that is done, the ion acoustic wave turns out to be heavily damped. If the electron mass is taken to be zero (electrons are Bolzmann-distributed), the perpendicular component of the surface current density vanishes, and we have the well-known ion acoustic surface wave eigenmode. We conclude that an ion acoustic surface wave propagates as an eigenmode only when its phase velocity is much smaller than the electron thermal velocity.
Quantum ion-acoustic oscillations in single-walled carbon nanotubes
Energy Technology Data Exchange (ETDEWEB)
Khan, S.A. [Kyoto Univ., Katsura (Japan). Graduate School of Engineering; Quaid-i-Azam Univ., Islamabad (Pakistan). National Centre for Physics; Iqbal, Z. [University of Management and Technology, Sialkot (Pakistan); Wazir, Z. [Riphah International Univ., Islamabad (Pakistan). Dept. of Basic Sciences; Rehman, Aman ur [Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad (Pakistan)
2016-08-01
Quantum ion-acoustic oscillations in single-walled carbon nanotubes are studied by employing a quantum hydrodynamics model. The dispersion equation is obtained by Fourier transformation, which exhibits the existence of quantum ion-acoustic wave affected by change of density balance due to presence of positive or negative heavy species as stationary ion clusters and wave potential at equilibrium. The numerical results are presented, and the role of quantum degeneracy, nanotube geometry, electron exchange-correlation effects, and concentration and polarity of heavy species on wave dispersion is pointed out for typical systems of interest.
Eigenvalue solution to the electron-collisional effect on ion-acoustic and entropy waves
Institute of Scientific and Technical Information of China (English)
ZHENG; Jian
2001-01-01
［1］Braginskii,S.I.,Transport processes in a plasma,in Reviews of Plasma Physics,Vol.1,New York:Consultants Bureau,1965,205-311.［2］Ono,M.,Kulsrud,R.M.,Frequency and damping of ion acoustic waves,Phys.Fluids,1975,18(10):1287-1293.［3］Randall,C.J.,Effect of ion collisionality on ion-acoustic waves,Phys.Fluids,1982,25(12):2231-2233.［4］Tracy,M.D.,Williams,E.A.,Estabrook,K.G.et al.,Eigenvalue solution for the ion-collisional effects on ion-acoustic and entropy waves,Phys.Fluids,1993,B5(5):1430.［5］Bell,A.R.,Electron energy transport in ion waves and its relevance to laser produced plasmas,Phys.Fluids,1983,26(1):279-284.［6］Epperlein,E.M.,Short,R.W.,Simon,A.,Damping of ion-acoustic waves in the presence of electron-ion collisions,Phys.Rev.Lett.,1992,69(12):1765-1768.［7］Epperlein,E.M.,Effect of electron collisions on ion-acoustic waves and heat flow,Phys.Plasmas,1994,1(1):109-115.［8］Bychenkov,V.Y.,Myatt,J.,Rozmus,W.et al.,Quasihydrodynamic description of ion acoustic waves in a collisional plasmas,Phys.Plasmas,1994,1(8):2419-2429.［9］Bychenkov,V.Y.,Myatt,J.,Rozmus,W.et al.,Ion acoustic waves in plasmas with collisional electrons,Phys.Rev.E,1994,50(6):5134-5137.［10］Bychenkov,V.Y.,Rozmus,W.,Tikhonchuk,V.T.et al.,Nonlocal electron transport in a plasma,Phys.Rev.Lett.,1995,75(24):4405-4408.［11］Zhang,Y.Q.et al.,Density fluctuation spectra of a collision-dominated plasma measured by light scattering,Phys.Rev.Lett.,1989,62(16):1848-1851.［12］Hinton,F.L.,Collisional transport in plasma,in Handbook of Plasma Physics,Vol.1,Amsterdam:North-Holland,1983,147-199.［13］Zheng Jian,Yu Changxuan,A numerical approach to the frequencies and damping rates of ion-acoustic waves in ion-collisional plasmas,Chin.Phys.Lett.,1999,16(12):905-907.［14］Hammett,G.W.,Perkins,F.,Fluid moment models for Landau damping with application to the ion-temperature-gradient instability,Phys.Rev.Lett.,1990,64(25):3019-3022.
A Comment on Interaction of Lower Hybrid Waves with the Current-Driven Ion-Acoustic Instability
DEFF Research Database (Denmark)
Schrittwieser, R.; Juul Rasmussen, Jens
1985-01-01
Majeski et al. (1984) have investigated the interaction between the current-driven 'ion-acoustic' instability and high frequency lower hybrid waves. The 'ion-acoustic' instability was excited by drawing an electron current through the plasma column of a single-ended Q-machine by means of a positi......Majeski et al. (1984) have investigated the interaction between the current-driven 'ion-acoustic' instability and high frequency lower hybrid waves. The 'ion-acoustic' instability was excited by drawing an electron current through the plasma column of a single-ended Q-machine by means...... of a positively biased cold plate. Schmittwieser et al. do not believe that the observed instability is of the ion-acoustic type but that it is rather the so-called potential relaxation instability....
Energy Technology Data Exchange (ETDEWEB)
Saberian, E. [Department of Physics, Faculty of Sciences, Azarbaijan Shahid Madani University, 53714-161 Tabriz (Iran, Islamic Republic of); Department of Physics, Faculty of Basic Sciences, University of Neyshabur, Neyshabur (Iran, Islamic Republic of); Esfandyari-Kalejahi, A.; Rastkar-Ebrahimzadeh, A.; Afsari-Ghazi, M. [Department of Physics, Faculty of Sciences, Azarbaijan Shahid Madani University, 53714-161 Tabriz (Iran, Islamic Republic of)
2013-03-15
The propagation of ion-acoustic (IA) solitons is studied in a plasma system, comprised of warm ions and superthermal (Kappa distributed) electrons in the presence of an electron-beam by using a hydrodynamic model. In the linear analysis, it is seen that increasing the superthermality lowers the phase speed of the IA waves. On the other hand, in a fully nonlinear investigation, the Mach number range and characteristics of IA solitons are analyzed, parametrically and numerically. It is found that the accessible region for the existence of IA solitons reduces with increasing the superthermality. However, IA solitons with both negative and positive polarities can coexist in the system. Additionally, solitary waves with both subsonic and supersonic speeds are predicted in the plasma, depending on the value of ion-temperature and the superthermality of electrons in the system. It is examined that there are upper critical values for beam parameters (i.e., density and velocity) after which, IA solitary waves could not propagate in the plasma. Furthermore, a typical interaction between IA waves and the electron-beam in the plasma is confirmed.
Small amplitude ion-acoustic double layers with cold electron beam and q-nonextensive electrons
Energy Technology Data Exchange (ETDEWEB)
Ali Shan, S., E-mail: shaukatshan@gmail.com [Theoretical Plasma Physics Division, PINSTECH, Nilore, 44000 Islamabad (Pakistan); National Centre for Physics (NCP), Shahdra Valley Road, 44000 Islamabad (Pakistan); Department of Mathematics and Applied Physics (DPAM), PIEAS, Islamabad (Pakistan); Saleem, H., E-mail: saleemhpk@hotmail.com [National Centre for Physics (NCP), Shahdra Valley Road, 44000 Islamabad (Pakistan); Department of Mathematics and Applied Physics (DPAM), PIEAS, Islamabad (Pakistan)
2014-02-01
Small amplitude ion-acoustic double layers in an unmagnetized and collisionless plasma consisting of cold positive ions, q-nonextensive electrons, and a cold electron beam are investigated. Small amplitude double layer solution is obtained by expanding the Sagdeev potential truncated method. The effects of entropic index q, speed and density of cold electron beam on double layer structures are discussed.
Laser Plasmas : Effect of rippled laser beam on excitation of ion acoustic wave
Indian Academy of Sciences (India)
Nareshpal Singh Saini; Tarsem Singh Gill
2000-11-01
Growth of a radially symmetrical ripple, superimposed on a Gaussian laser beam in collisional unmagnetised plasma is investigated. From numerical computation, it is observed that self-focusing of main beam as well as ripple determine the growth dynamics of ripple with the distance of propagation. The effect of growing ripple on excitation of ion acoustic wave (IAW) has also been studied
Peakons and new exact solitary wave solutions of extended quantum Zakharov-Kuznetsov equation
Zhang, Ben-gong; Li, Weibo; Li, Xiangpeng
2017-06-01
In this paper, the three dimensional extended quantum Zakharov-Kuznetsov equation, which arises in the dimensionless hydrodynamic equations describing the nonlinear propagation of the quantum ion-acoustic waves, is investigated by an auxiliary equation method. As a result, peakons and a series of new exact traveling wave solutions, including bell-shaped, kink-type solitary wave, shock wave, periodic wave, and Jacobi elliptic solutions, are obtained. We also analyze the three kinds of nonlinear structures of our results, i.e., blowup, peakons, and shock wave. These new exact solutions will enrich the previous results and help us to further understand the physical structures and analyze the nonlinear propagation of the quantum ion-acoustic waves.
Excitation of Ion Acoustic Waves in Confined Plasmas with Untrapped Electrons
Schamis, Hanna; Dow, Ansel; Carlsson, Johan; Kaganovich, Igor; Khrabrov, Alexander
2015-11-01
Various plasma propulsion devices exhibit strong electron emission from the walls either as a result of secondary processes or due to thermionic emission. To understand the electron kinetics in plasmas with strong emission, we have performed simulations using a reduced model with the LSP particle-in-cell code. This model aims to show the instability generated by the electron emission, in the form of ion acoustic waves near the sheath. It also aims to show the instability produced by untrapped electrons that propagate across the plasma, similarly to a beam, and can drive ion acoustic waves in the plasma bulk. This work was made possible by funding from the Department of Energy for the Summer Undergraduate Laboratory Internship (SULI) program. This work is supported by the US DOE Contract No.DE-AC02-09CH11466.
Hafez, M. G.; Talukder, M. R.; Hossain Ali, M.
2017-04-01
The Burgers equation is obtained to study the characteristics of nonlinear propagation of ionacoustic shock, singular kink, and periodic waves in weakly relativistic plasmas containing relativistic thermal ions, nonextensive distributed electrons, Boltzmann distributed positrons, and kinematic viscosity of ions using the well-known reductive perturbation technique. This equation is solved by employing the ( G'/ G)-expansion method taking unperturbed positron-to-electron concentration ratio, electron-to-positron temperature ratio, strength of electrons nonextensivity, ion kinematic viscosity, and weakly relativistic streaming factor. The influences of plasma parameters on nonlinear propagation of ion-acoustic shock, periodic, and singular kink waves are displayed graphically and the relevant physical explanations are described. It is found that these parameters extensively modify the shock structures excitation. The obtained results may be useful in understanding the features of small but finite amplitude localized relativistic ion-acoustic shock waves in an unmagnetized plasma system for some astrophysical compact objects and space plasmas.
Directory of Open Access Journals (Sweden)
M. G. Hafez
2016-01-01
Full Text Available Two-dimensional three-component plasma system consisting of nonextensive electrons, positrons, and relativistic thermal ions is considered. The well-known Kadomtsev-Petviashvili-Burgers and Kadomtsev-Petviashvili equations are derived to study the basic characteristics of small but finite amplitude ion acoustic waves of the plasmas by using the reductive perturbation method. The influences of positron concentration, electron-positron and ion-electron temperature ratios, strength of electron and positrons nonextensivity, and relativistic streaming factor on the propagation of ion acoustic waves in the plasmas are investigated. It is revealed that the electrostatic compressive and rarefactive ion acoustic waves are obtained for superthermal electrons and positrons, but only compressive ion acoustic waves are found and the potential profiles become steeper in case of subthermal positrons and electrons.
Effects of ion-atom collisions on the propagation and damping of ion-acoustic waves
DEFF Research Database (Denmark)
Andersen, H.K.; D'Angelo, N.; Jensen, Vagn Orla;
1968-01-01
Experiments are described on ion-acoustic wave propagation and damping in alkali plasmas of various degrees of ionization. An increase of the ratio Te/Ti from 1 to approximately 3-4, caused by ion-atom collisions, results in a decrease of the (Landau) damping of the waves. At high gas pressure and....../or low wave frequency a "fluid" picture adequately describes the experimental results....
Eigenvalue solution to the electron-collisional effect on ion-acoustic and entropy waves
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The linearized electron Fokker-Planck and cold-ion fluid equations are solved as an eigenvalue problem in the quasineutral limit for ionization state,Z=1,8,and 64 for ion-acoustic and entropy waves.The perturbed electron distribution function is written as a moment expansion of eigenvectors,and is used to compute collisionality-dependence macroscopic quantities in the plasma such as the generalized specific heat ratio,and the electron thermal conductivity.
Solitary and double-layer structures in quantum bi-ion plasma
Shahmansouri, Mehran; Tribeche, Mouloud
2016-06-01
Weak ion-acoustic solitary waves (IASWs) in an unmagnetized quantum plasmas having two-fluid ions and fluid electrons are considered. Using the one-dimensional quantum hydrodynamics model and then the reductive perturbation technique, a generalized form of nonlinear quantum Korteweg-de Vries (KdV) equation governing the dynamics of weak ion acoustic solitary waves is derived. The effects of ion population, warm ion temperature, quantum diffraction, and polarity of ions on the nonlinear properties of these IASWs are analyzed. It is found that our present plasma model may support compressive as well as rarefactive solitary structures. Furthermore, formation and characteristics properties of IA double layers in the present bi-ion plasma model are investigated. The results of this work should be useful and applicable in understanding the wide relevance of nonlinear features of localized electro-acoustic structures in laboratory and space plasma, such as in super-dense astrophysical objects [24] and in the Earth's magnetotail region (Parks [43]. The implications of our results in some space plasma situations are discussed.
Energy Technology Data Exchange (ETDEWEB)
Rietveld, M.T. (EISCAT, Ramfjordbotn (Norway)); Collis, P.N. (EISCAT, Kiruna (Sweden)); St.Maurice, J.P. (Univ. of Western Ontario, London (Canada))
1991-11-01
Observations of strongly enhanced ion acoustic shoulders of the incoherent scatter spectrum at 933 MHz at altitudes from 138 to 587 km have been obtained with the European Incoherent Scatter UHF radar. The enhancements can be up to 1 or 2 orders of magnitude in total backscattered power and can occur at either one or both of the ion acoustic shoulders. They show a variation of frequency with height of about 2 to 1, the same as the normal ion line spectral width and the ion temperature. These unusual spectra appear in two preferred height regions having different characteristics, one below 200 km and one above about 300 km. The enhancements are associated with geomagnetic disturbance, high electron temperatures, auroral arcs, and red aurora in the F region. The observations, which are mainly along the magnetic field direction, indicate that field-aligned thermal electron drifts are destabilizing the ion acoustic waves. The confirm and extend the one other publication reporting on similar echoes. The authors suggest that field-aligned flows of soft electrons depositing their energy at horizontally poor conducting F region heights are the cause of parallel electric fields in the ionosphere. These fields then produce the thermal electron motions that they argue have to be the cause of the observations.
Ion-Acoustic Instability in the Presence of High Frequency Oscillations
DEFF Research Database (Denmark)
Juul Rasmussen, Jens; Sandu, D.; Schrittwieser, R.
1977-01-01
Measurements are presented of a standing ion-acoustic wave instability, which is excited by a positively biased grid inserted perpendicularly into the plasma column of a single-ended Q-machine, under the influence of a high frequency signal superimposed onto the positive voltage at the grid....... The experimental results show that in certain regions of the frequency and amplitude of the h.f. signal the ion wave instability is stabilized or destabilized. A possible explanation of these effects is presented....
Two different types of enhanced ion acoustic fluctuations observed in the upper ionosphere
Energy Technology Data Exchange (ETDEWEB)
Forme, F.R.E.; Fontaine, D.; Wahlund, J.E. [Centre d`etude des Environnements Terrestre et Planetaires, Velizy (France)
1995-08-01
UHF and VHF data for the EISCAT incoherent scatter radar facility in northern Scandinavia is presented. Electron and ion temperatures, electron density, and ion drift velocity were measured from heights of 280 to 1500 km. Enhanced ion acoustic fluctuations are more observable with VHF than UHF radar due to wavelength effects. The fluctuations are usually associated with a large flux of precipitating electrons with energies from 100 ev to 10 kev. The spatial extent of the turbulent regions are determined. 23 refs., 6 figs.
Nonplanar ion-acoustic shocks in electron–positron–ion plasmas: Effect of superthermal electrons
Indian Academy of Sciences (India)
Deb Kumar Ghosh; Prasantha Chatterjee; Pankaj Kumar Mandal; Biswajit Sahu
2013-09-01
Ion-acoustic shock waves (IASWs) in a homogeneous unmagnetized plasma, comprising superthermal electrons, positrons, and singly charged adiabatically hot positive ions are investigated via two-dimensional nonplanar Kadomstev–Petviashvili–Burgers (KPB) equation. It is found that the profiles of the nonlinear shock structures depend on the superthermality of electrons. The influence of other plasma parameters such as, ion kinematic viscosity and ion temperature, is discussed in the presence of superthermal electrons in nonplanar geometry. It is also seen that the IASWs propagating in cylindrical/spherical geometry with transverse perturbation will be deformed as time goes on.
Ion-acoustic double layers in the presence of plasma source
Energy Technology Data Exchange (ETDEWEB)
Okuda, H.; Ashour-Abdalla, M.
1981-11-01
Steady-state plasma turbulence and formation of negative potential spikes and double layers in the presence of ion acoustic instabilities have been studied by means of one-dimensional particle simulations in which velocities of a small fraction of electrons are replaced by the initial drifting Maxwellian at a constant rate. A steady state is found where negative potential spikes appear randomly in space and time giving rise to an anomalous resistivity much greater than previously found. Comparisons of the simulation results with laboratory and space plasmas are discussed.
Energy Properties of Ion Acoustic Waves in Stable and Unstable Plasmas
DEFF Research Database (Denmark)
Jensen, Vagn Orla; Lynov, Jens-Peter
1979-01-01
acoustic waves that are growing or damped in space the time average of the sum of the potential and the kinetic energy density is independent of position. Energy absorption spectra in particle velocity space are calculated; they are relatively broad and complicated functions. This shows that plasma ions......Energy exchange between potential energy and ion kinetic energy in an ion acoustic wave is considered. In order to investigate the linear Landau damping or growth, the energy is calculated by use of first‐order quantities only so that nonlinear effects are not involved. It is found that for ion...
Time fractional effect on ion acoustic shock waves in ion-pair plasma
Energy Technology Data Exchange (ETDEWEB)
Abdelwahed, H. G., E-mail: hgomaa-eg@hotmail.com [Prince Sattam Bin Abdulaziz University, College of Science and Humanitarian Studies, Physics Department (Saudi Arabia); El-Shewy, E. K.; Mahmoud, A. A. [Faculty of Science, Mansoura University, Theoretical Physics Group, Physics Department (Egypt)
2016-06-15
The nonlinear properties of ion acoustic shock waves are studied. The Burgers equation is derived and converted into the time fractional Burgers equation by Agrawal’s method. Using the Adomian decomposition method, shock wave solutions of the time fractional Burgers equation are constructed. The effect of the time fractional parameter on the shock wave properties in ion-pair plasma is investigated. The results obtained may be important in investigating the broadband electrostatic shock noise in D- and F-regions of Earth’s ionosphere.
Ion acoustic waves at comet 67P/Churyumov-Gerasimenko. Observations and computations
Gunell, H.; Nilsson, H.; Hamrin, M.; Eriksson, A.; Odelstad, E.; Maggiolo, R.; Henri, P.; Vallieres, X.; Altwegg, K.; Tzou, C.-Y.; Rubin, M.; Glassmeier, K.-H.; Stenberg Wieser, G.; Simon Wedlund, C.; De Keyser, J.; Dhooghe, F.; Cessateur, G.; Gibbons, A.
2017-03-01
Context. On 20 January 2015 the Rosetta spacecraft was at a heliocentric distance of 2.5 AU, accompanying comet 67P/Churyumov-Gerasimenko on its journey toward the Sun. The Ion Composition Analyser (RPC-ICA), other instruments of the Rosetta Plasma Consortium, and the ROSINA instrument made observations relevant to the generation of plasma waves in the cometary environment. Aims: Observations of plasma waves by the Rosetta Plasma Consortium Langmuir probe (RPC-LAP) can be explained by dispersion relations calculated based on measurements of ions by the Rosetta Plasma Consortium Ion Composition Analyser (RPC-ICA), and this gives insight into the relationship between plasma phenomena and the neutral coma, which is observed by the Comet Pressure Sensor of the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis instrument (ROSINA-COPS). Methods: We use the simple pole expansion technique to compute dispersion relations for waves on ion timescales based on the observed ion distribution functions. These dispersion relations are then compared to the waves that are observed. Data from the instruments RPC-LAP, RPC-ICA and the mutual impedance probe (RPC-MIP) are compared to find the best estimate of the plasma density. Results: We find that ion acoustic waves are present in the plasma at comet 67P/Churyumov-Gerasimenko, where the major ion species is H2O+. The bulk of the ion distribution is cold, kBTi = 0.01 eV when the ion acoustic waves are observed. At times when the neutral density is high, ions are heated through acceleration by the solar wind electric field and scattered in collisions with the neutrals. This process heats the ions to about 1 eV, which leads to significant damping of the ion acoustic waves. Conclusions: In conclusion, we show that ion acoustic waves appear in the H2O+ plasmas at comet 67P/Churyumov-Gerasimenko and how the interaction between the neutral and ion populations affects the wave properties. Computer code for the dispersion analysis is
Energy Technology Data Exchange (ETDEWEB)
Olivier, C. P., E-mail: colivier@sansa.org.za; Maharaj, S. K., E-mail: smaharaj@sansa.org.za [South African National Space Agency (SANSA) Space Science, P. O. Box 32, Hermanus 7200 (South Africa); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Robert Sobukwe Road, Bellville 7535 (South Africa)
2015-08-15
The polarity of ion-acoustic solitons that arise in a plasma with two (same mass, different temperature) ion species and two (different temperature) electron species is investigated. Two different fluid models are compared. The first model treats all species as adiabatic fluids, while the second model treats the ion species as adiabatic, and the electron species as isothermal. Nonlinear structures are analysed via the reductive perturbation analysis and pseudo-potential analysis. Each model supports both slow and fast ion-acoustic solitons, associated with the two (slow and fast) ion-acoustic speeds. The models support both positive and negative polarity solitons associated with the slow ion-acoustic speed. Moreover, results are in good agreement, and both models support positive and negative polarity double layers. For the fast ion-acoustic speed, the first model supports only positive polarity solitons, while the second model supports solitons of both polarity, coexistence of positive and negative polarity solitons, double layers and supersolitons. A novel feature of our analysis is the evaluation of nonlinear structures at critical number densities where polarity changes occur. This analysis shows that solitons that occur at the acoustic speed are neither a necessary nor a sufficient condition for the phenomenon of coexistence. The relationship between the existence regions of supersolitons and soliton polarity is also discussed.
Mishra, M. K.; Jain, S. K.; Jain
2013-10-01
Ion-acoustic solitons in magnetized low-β plasma consisting of warm adiabatic positive and negative ions and non-thermal electrons have been studied. The reductive perturbation method is used to derive the Korteweg-de Vries (KdV) equation for the system, which admits an obliquely propagating soliton solution. It is found that due to the presence of finite ion temperature there exist two modes of propagation, namely fast and slow ion-acoustic modes. In the case of slow-mode if the ratio of temperature to mass of positive ion species is lower (higher) than the negative ion species, then there exist compressive (rarefactive) ion-acoustic solitons. It is also found that in the case of slow mode, on increasing the non-thermal parameter (γ) the amplitude of the compressive (rarefactive) soliton decreases (increases). In fast ion-acoustic mode the nature and characteristics of solitons depend on negative ion concentration. Numerical investigation in case of fast mode reveals that on increasing γ, the amplitude of compressive (rarefactive) soliton increases (decreases). The width of solitons increases with an increase in non-thermal parameters in both the modes for compressive as well as rarefactive solitons. There exists a value of critical negative ion concentration (α c ), at which both compressive and rarefactive ion-acoustic solitons appear as described by modified KdV soliton. The value of α c decreases with increase in γ.
Indian Academy of Sciences (India)
Hong-Yan Wang; Kai-Biao Zhang
2015-01-01
Propagation of small but finite nonlinear dust-acoustic solitary waves are investigated in a planar unmagnetized dusty plasma, which consists of electrons, positrons, ions and negatively charged dust particles with different sizes and masses. A Kadomtsev–Petviashvili (KP) equation is obtained by using reductive perturbation method. The effect of positron density and positron–electron temperature ratio on dust-acoustic solitary structures are studied. Numerical results show that the increase in positron number density increases the amplitude of hump-like solitons but decreases the dip-like solitary waves. Furthermore, increase in the positron–electron temperature ratio results in the decrease of the amplitude of dip-like solitary waves. It seems that both the dipand hump-like solitary waves can exist in this system. Our results also suggest that the dust-size distribution has a significant role on the amplitude of the solitary waves.
DEFF Research Database (Denmark)
Henriksen, Casper Christian I
Summary: The effects of farming system, flower resources and semi-natural habitats on bumblebees and solitary bees in intensively cultivated landscapes in Denmark were investigated in two sets of studies, in 2011 and 2012. The pan trap colour preferences of bumblebees and solitary bees were also...... assessed. In 2011, bumblebees and solitary bees were trapped in road verges bordering 14 organic (organic sites) and 14 conventional (conventional sites) winter wheat fields. The quantity and quality of local flower resources in the road verge and adjacent field headland were estimated as overall density...... use as a proxy at four different scales (250, 500, 750 and 1000 m). In 2012, the effect of a four-fold larger area of organic arable fields in simple, homogeneous landscapes on bumblebees and solitary bees was investigated in eight circular landscapes (radius 1000 m). Bumblebees and solitary bees were...
Ion-acoustic cnoidal waves in plasmas with warm ions and kappa distributed electrons and positrons
Energy Technology Data Exchange (ETDEWEB)
Kaladze, T. [Department of Physics, Government College University (GCU), Lahore 54000 (Pakistan); I.Vekua Institute of Applied Mathematics, Tbilisi State University, 0186 Georgia (United States); Mahmood, S., E-mail: shahzadm100@gmail.com [Theoretical Physics Division (TPD), PINSTECH P.O. Nilore Islamabad 44000 (Pakistan); National Center for Physics (NCP), Quaid-i-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)
2014-03-15
Electrostatic ion-acoustic periodic (cnoidal) waves and solitons in unmagnetized electron-positron-ion (EPI) plasmas with warm ions and kappa distributed electrons and positrons are investigated. Using the reductive perturbation method, the Korteweg-de Vries (KdV) equation is derived with appropriate boundary conditions for periodic waves. The corresponding analytical and various numerical solutions are presented with Sagdeev potential approach. Differences between the results caused by the kappa and Maxwell distributions are emphasized. It is revealed that only hump (compressive) structures of the cnoidal waves and solitons are formed. It is shown that amplitudes of the cnoidal waves and solitons are reduced in an EPI plasma case in comparison with the ordinary electron-ion plasmas. The effects caused by the temperature variations of the warm ions are also discussed. It is obtained that the amplitude of the cnoidal waves and solitons decreases for a kappa distributed (nonthermal) electrons and positrons plasma case in comparison with the Maxwellian distributed (thermal) electrons and positrons EPI plasmas. The existence of kappa distributed particles leads to decreasing of ion-acoustic frequency up to thermal ions frequency.
Ion-acoustic solitons in negative ion plasma with two-electron temperature distributions
Energy Technology Data Exchange (ETDEWEB)
Mishra, M. K.; Tiwari, R. S.; Chawla, J. K. [Department of Physics, University of Rajasthan, Jaipur-302004 (India)
2012-06-15
Ion-acoustic solitons in a warm positive and negative ion species with different masses, concentrations, and charge states with two electron temperature distributions are studied. Using reductive perturbation method, Korteweg de-Vries (KdV) and modified-KdV (m-KdV) equations are derived for the system. The soliton solution of the KdV and m-KdV equations is discussed in detail. It is found that if the ions have finite temperatures, then there exist two types of modes, namely slow and fast ion-acoustic modes. It is also investigated that the parameter determining the nature of soliton (i.e., whether the system will support compressive or rarefactive solitons) is different for slow and fast modes. For the slow mode, the parameter is the relative temperature of the two ion species; whereas for the fast mode, it is the relative concentration of the two ion species. At a critical concentration of negative ions, both compressive and rarefactive solitons coexist. The amplitude and width of the solitons are discussed in detail at critical concentration for m-KdV solitons. The effect of the relative temperature of the two-electron and cold-electron concentration on the characteristics of the solitons are also discussed.
Ion-acoustic cnoidal waves in plasmas with warm ions and kappa distributed electrons and positrons
Kaladze, T.; Mahmood, S.
2014-03-01
Electrostatic ion-acoustic periodic (cnoidal) waves and solitons in unmagnetized electron-positron-ion (EPI) plasmas with warm ions and kappa distributed electrons and positrons are investigated. Using the reductive perturbation method, the Korteweg-de Vries (KdV) equation is derived with appropriate boundary conditions for periodic waves. The corresponding analytical and various numerical solutions are presented with Sagdeev potential approach. Differences between the results caused by the kappa and Maxwell distributions are emphasized. It is revealed that only hump (compressive) structures of the cnoidal waves and solitons are formed. It is shown that amplitudes of the cnoidal waves and solitons are reduced in an EPI plasma case in comparison with the ordinary electron-ion plasmas. The effects caused by the temperature variations of the warm ions are also discussed. It is obtained that the amplitude of the cnoidal waves and solitons decreases for a kappa distributed (nonthermal) electrons and positrons plasma case in comparison with the Maxwellian distributed (thermal) electrons and positrons EPI plasmas. The existence of kappa distributed particles leads to decreasing of ion-acoustic frequency up to thermal ions frequency.
High time resolution PFISR and optical observations of naturally enhanced ion acoustic lines
Directory of Open Access Journals (Sweden)
R. G. Michell
2009-04-01
Full Text Available Observations of naturally enhanced ion acoustic lines (NEIALs taken with the Poker Flat Incoherent Scatter Radar (PFISR using a mode with very high time resolution are presented. The auroral event took place over Poker Flat, Alaska on 8 February 2007 at 09:35 UT (~22:00 MLT, and the radar data are complemented by common-volume high-resolution auroral imaging. The NEIALs occurred during only one of the standard 15-s integration periods. The raw data of this time show very intermittent NEIALs which occur only during a few very short time intervals (≤1 s within the 15-s period. The time sampling of the raw data, ~19 ms on average, allows study of the time development of the NEIALs, though there are indications that even finer time resolution would be of interest. The analysis is based on the assumption that the NEIAL returns are the result of Bragg scattering from ion-acoustic waves that have been enhanced significantly above thermal levels. The spectra of the raw data indicate that although the up- and down-shifted shoulders can both become enhanced at the same time, (within 19 ms, they are most often enhanced individually. The overall power in the up-and down-shifted shoulders is approximately equal throughout the event, with the exception of one time, when very large up-shifted power was observed with no corresponding down-shifted power. This indicates that during the 480 μs pulse, the strongly enhanced ion-acoustic waves were only traveling downward and not upward. The exact time that the NEIALs occurred was when the radar beam was on the boundary of a fast-moving (~10 km/s, bright auroral structure, as seen in the high resolution auroral imaging of the magnetic zenith. When viewed with high time resolution, the occurrence of NEIALs is associated with rapid changes in auroral luminosity within the radar field of view due to fast-moving auroral fine structures.
Dust acoustic waves in an inhomogeneous plasma having dust size distribution
Banerjee, Gadadhar; Maitra, Sarit
2017-07-01
Propagations of nonlinear dust acoustic solitary waves in an inhomogeneous unmagnetized dusty plasma having power law dust distribution are investigated. Using a reductive perturbation technique, a variable coefficient deformed Korteweg-deVries (VCdKdV) equation is derived from the basic set of hydrodynamic equations. The generalized expansion method is employed to obtain a solitary wave solution for the VCdKdV equation. The different propagation characteristics of the solitary waves are studied in the presence of both plasma inhomogeneity and dust distribution.
Saleem, H.; Ali Shan, S.; Haque, Q.
2016-11-01
It is shown that the inhomogeneous field-aligned flow of heavier ions into the stationary plasma of the upper ionosphere produces very low frequency (of the order of a few Hz) electrostatic unstable ion acoustic waves (IAWs). This instability is an oscillatory instability unlike D'Angelo's purely growing mode. The growth rate of the ion acoustic wave (IAW) corresponding to heavier ions is due to shear flow and is larger than the ion Landau damping. However, the ion acoustic waves corresponding to non-flowing lighter ions are Landau damped. It is found that even if D'Angelo's instability condition is satisfied, the unstable mode develops its real frequency in this coupled system. Hence, the shear flow of one type of ions in a bi-ion plasma system produces ion acoustic wave activity. If the density non-uniformity is taken into account, then the drift wave becomes unstable. The coupled nonlinear equations for stationary ions "a," flowing ions "b," and inertialess electrons are also solved using the small amplitude limit. The solutions predict the existence of the order of a few kilometers electric field structures in the form of solitons and vortices, which is in agreement with the satellite observations.
Ion-acoustic shocks with reflected ions: modeling and PIC simulations
Liseykina, T; Vshivkov, V; Malkov, M
2015-01-01
Non-relativistic collisionless shock waves are widespread in space and astrophysical plasmas and are known as efficient particle accelerators. However, our understanding of collisionless shocks, including their structure and the mechanisms whereby they accelerate particles remains incomplete. We present here the results of numerical modeling of an ion-acoustic collisionless shock based on one-dimensional (1D) kinetic approximation both for electrons and ions with a real mass ratio. Special emphasis is made on the shock-reflected ions as the main driver of shock dissipation. The reflection efficiency, velocity distribution of reflected particles and the shock electrostatic structure are studied in terms of the shock parameters. Applications to particle acceleration in geophysical and astrophysical shocks are discussed.
Weakly nonlinear ion-acoustic excitations in a relativistic model for dense quantum plasma.
Behery, E E; Haas, F; Kourakis, I
2016-02-01
The dynamics of linear and nonlinear ionic-scale electrostatic excitations propagating in a magnetized relativistic quantum plasma is studied. A quantum-hydrodynamic model is adopted and degenerate statistics for the electrons is taken into account. The dispersion properties of linear ion acoustic waves are examined in detail. A modified characteristic charge screening length and "sound speed" are introduced, for relativistic quantum plasmas. By employing the reductive perturbation technique, a Zakharov-Kuznetzov-type equation is derived. Using the small-k expansion method, the stability profile of weakly nonlinear slightly supersonic electrostatic pulses is also discussed. The effect of electron degeneracy on the basic characteristics of electrostatic excitations is investigated. The entire analysis is valid in a three-dimensional as well as in two-dimensional geometry. A brief discussion of possible applications in laboratory and space plasmas is included.
Ion acoustic shock waves in plasmas with warm ions and kappa distributed electrons and positrons
Energy Technology Data Exchange (ETDEWEB)
Hussain, S.; Mahmood, S.; Hafeez Ur-Rehman [Theoretical Plasma Physics Division, PINSTECH, P.O. Nilore, Islamabad 44000, Pakistan and Department of Physics and Applied Mathematics, PIEAS, P.O. Nilore, Islamabad 44000 (Pakistan)
2013-06-15
The monotonic and oscillatory ion acoustic shock waves are investigated in electron-positron-ion plasmas (e-p-i) with warm ions (adiabatically heated) and nonthermal kappa distributed electrons and positrons. The dissipation effects are included in the model due to kinematic viscosity of the ions. Using reductive perturbation technique, the Kadomtsev-Petviashvili-Burgers (KPB) equation is derived containing dispersion, dissipation, and diffraction effects (due to perturbation in the transverse direction) in e-p-i plasmas. The analytical solution of KPB equation is obtained by employing tangent hyperbolic (Tanh) method. The analytical condition for the propagation of oscillatory and monotonic shock structures are also discussed in detail. The numerical results of two dimensional monotonic shock structures are obtained for graphical representation. The dependence of shock structures on positron equilibrium density, ion temperature, nonthermal spectral index kappa, and the kinematic viscosity of ions are also discussed.
Energy Technology Data Exchange (ETDEWEB)
Follett, R. K., E-mail: rfollett@lle.rochester.edu; Delettrez, J. A.; Edgell, D. H.; Henchen, R. J.; Katz, J.; Myatt, J. F.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States)
2016-11-15
Collective Thomson scattering is a technique for measuring the plasma conditions in laser-plasma experiments. Simultaneous measurements of ion-acoustic and electron plasma-wave spectra were obtained using a 263.25-nm Thomson-scattering probe beam. A fully reflective collection system was used to record light scattered from electron plasma waves at electron densities greater than 10{sup 21} cm{sup −3}, which produced scattering peaks near 200 nm. An accurate analysis of the experimental Thomson-scattering spectra required accounting for plasma gradients, instrument sensitivity, optical effects, and background radiation. Practical techniques for including these effects when fitting Thomson-scattering spectra are presented and applied to the measured spectra to show the improvements in plasma characterization.
Characterization of Ion-Acoustic Wave Reflection Off A Plasma Chamber Wall
Berumen, Jorge; Chu, Feng; Hood, Ryan; Mattingly, Sean; Rogers, Anthony; Skiff, Fred
2015-11-01
We present an experimental characterization of the ion acoustic wave reflection coefficient off a plasma chamber wall. The experiment is performed in a cylindrical, magnetized, singly-ionized Argon inductively-coupled gas discharge plasma that is weakly collisional with typical conditions: n ~ 1010cm-3 Te ~ 3 eV and B ~ 1 kG. The main diagnostics are laser-induced fluorescence and Langmuir probe measurements. A survey of the ion velocity distribution function's zeroth and first order as well as density fluctuations at different wave excitation frequencies is obtained. Analysis of the reflection coefficient's dependence on the phase velocity and frequency of the wave is done through the characterization of waves utilizing Case-Van Kampen modes and the use of Morrison's G-transform. This research is supported by the Department of Energy under grant No. DOE DE-FG02-99ER54543.
Farhad Kiyaei, Forough; Dorranian, Davoud
2017-01-01
Effects of the obliqueness and the strength of external magnetic field on the ion acoustic (IA) cnoidal wave in a nonextensive plasma are investigated. The reductive perturbation method is employed to derive the corresponding KdV equation for the IA wave. Sagdeev potential is extracted, and the condition of generation of IA waves in the form of cnoidal waves or solitons is discussed in detail. In this work, the domain of allowable values of nonextensivity parameter q for generation of the IA cnoidal wave in the plasma medium is considered. The results show that only the compressive IA wave may generate and propagate in the plasma medium. Increasing the strength of external magnetic field will increase the frequency of the wave and decrease its amplitude, while increasing the angle of propagation will decrease the frequency of the wave and increase its amplitude.
Numerical study of ion acoustic shock waves in dense quantum plasma
Energy Technology Data Exchange (ETDEWEB)
Hanif, M.; Mirza, Arshad M. [Theoretical Plasma Physics Group, Department of Physics, Quaid-e-Azam University, Islamabad 45320 (Pakistan); Ali, S.; Mukhtar, Q., E-mail: qaisarm@ncp.edu.pk [National Center for Physics, Quaid-e-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)
2014-03-15
Two fluid quantum hydrodynamic equations are solved numerically to investigate the propagation characteristics of ion acoustic shock waves in an unmagnetized dense quantum plasma, whose constituents are the electrons and ions. For this purpose, we employ the standard finite difference Lax Wendroff and relaxation methods, to examine the quantum effects on the profiles of shock potential, the electron/ion number densities, and velocity even for quantum parameter at H = 2. The effects of the latter vanish in a weakly non-linear limit while obeying the KdV theory. It is shown that the evolution of the wave depends sensitively on the plasma density and the quantum parameter. Numerical results reveal that the kinks or oscillations are pronounced for large values of quantum parameter, especially at H = 2. Our results should be important to understand the shock wave excitations in dense quantum plasmas, white dwarfs, neutron stars, etc.
The frequency and damping of ion acoustic waves in collisional and collisionless two-species plasma
Energy Technology Data Exchange (ETDEWEB)
Berger, R L; Valeo, E J
2004-07-15
The dispersion properties of ion acoustic waves (IAW) are sensitive to the strength of ion-ion collisions in multi-species plasma in which the different species usually have differing charge-to-mass ratios. The modification of the frequency and damping of the fast and slow acoustic modes in a plasma composed of light (low Z) and heavy (high Z) ions is considered. In the fluid limit where the light ion scattering mean free path, {lambda}{sub th} is smaller than the acoustic wavelength, {lambda} = 2{pi}/k, the interspecies friction and heat flow carried by the light ions scattering from the heavy ions causes the damping. In the collisionless limit, k{lambda}{sub lh} >> 1, Landau damping by the light ions provides the dissipation. In the intermediate regime when k{lambda}{sub lh} {approx} 1, the damping is at least as large as the sum of the collisional and Landau damping.
The Frequency and Damping of Ion Acoustic Waves in Collisional and Collisionless Two-species Plasma
Energy Technology Data Exchange (ETDEWEB)
R.L. Berger; E.J. Valeo
2004-08-18
The dispersion properties of ion acoustic waves (IAW) are sensitive to the strength of ion-ion collisions in multi-species plasma in which the different species usually have differing charge-to-mass ratios. The modification of the frequency and damping of the fast and slow acoustic modes in a plasma composed of light (low Z) and heavy (high Z) ions is considered. In the fluid limit where the light ion scattering mean free path, {lambda}{sub th} is smaller than the acoustic wavelength, {lambda} = 2{pi}/k, the interspecies friction and heat flow carried by the light ions scattering from the heavy ions causes the damping. In the collisionless limit, k{lambda}{sub th} >> 1, Landau damping by the light ions provides the dissipation. In the intermediate regime when k{lambda}{sub th} {approx} 1, the damping is at least as large as the sum of the collisional and Landau damping.
Large-amplitude ion-acoustic double layers in multispecies plasma
Jain, S. L.; Tiwari, R. S.; Sharma, S. R.
1990-06-01
The effect of second-ion species on the characteristics of large-amplitude ion-acoustic double layers (IADL) in a collisionless, unmagnetized plasma (consisting of hot and cold Maxwellian populations of electrons and two cold-ion species with different masses, concentrations, and charge states) is investigated. After deriving the criteria for the existence of large-amplitude IADL, it is found that the presence of a positive-ion impurity does not considerably modify the characteristics of large-amplitude IADL. However, the presence of negative-ion impurity significantly changes the characteristics of a large-amplitude IADL. An analytic discussion of small-amplitude IADL using a reductive perturbation method is also presented.
Ion-Acoustic Wave Scattering description using Case-Van Kampen modes
Berumen, Jorge; Chu, Feng; Hood, Ryan; Mattingly, Sean; Skiff, Fred
2016-10-01
We present an experimental characterization of the ion acoustic wave scattering using Case-Van Kampen modes. The experiment is performed in a cylindrical, magnetized, singly-ionized Argon inductively-coupled gas discharge plasma that is weakly collisional with typical conditions: n 109cm-3 Te 7 eV and B 1 kG. A 5 ring antenna with diameter similar to the plasma diameter is used for launching the waves. A survey of the ion velocity distribution function's zeroth and first order as well as density fluctuations at different frequencies is done using Laser-Induced Fluorescence (LIF) as the main diagnostics method. Analysis of the scattering of the waves and its dependence on wave frequency is done utilizing Case-Van Kampen modes and the use of Morrison's G-transform. This research is supported by the Department of Energy under Grant No. DOE DE-FG02-99ER54543.
Non-resonant interacting ion acoustic waves in a magnetized plasma
Energy Technology Data Exchange (ETDEWEB)
Maccari, Attilio [Technical Institute ' G Cardano' , Monterotondo, Rome (Italy)
1999-01-29
We perform an analytical and numerical investigation of the interaction among non-resonant ion acoustic waves in a magnetized plasma. Waves are supposed to be non-resonant, i.e. with different group velocities that are not close to each other. We use an asymptotic perturbation method, based on Fourier expansion and spatio-temporal rescaling. We show that the amplitude slow modulation of Fourier modes cannot be described by the usual nonlinear Schroedinger equation but by a new model system of nonlinear evolution equations. This system is C-integrable, i.e. it can be linearized through an appropriate transformation of the dependent and independent variables. We demonstrate that a subclass of solutions gives rise to envelope solitons. Each envelope soliton propagates with its own group velocity. During a collision solitons maintain their shape, the only change being a phase shift. Numerical results are used to check the validity of the asymptotic perturbation method. (author)
Follett, R. K.; Delettrez, J. A.; Edgell, D. H.; Henchen, R. J.; Katz, J.; Myatt, J. F.; Froula, D. H.
2016-11-01
Collective Thomson scattering is a technique for measuring the plasma conditions in laser-plasma experiments. Simultaneous measurements of ion-acoustic and electron plasma-wave spectra were obtained using a 263.25-nm Thomson-scattering probe beam. A fully reflective collection system was used to record light scattered from electron plasma waves at electron densities greater than 1021 cm-3, which produced scattering peaks near 200 nm. An accurate analysis of the experimental Thomson-scattering spectra required accounting for plasma gradients, instrument sensitivity, optical effects, and background radiation. Practical techniques for including these effects when fitting Thomson-scattering spectra are presented and applied to the measured spectra to show the improvements in plasma characterization.
Solitary and shock structures in a strongly coupled cryogenic quantum plasma
Energy Technology Data Exchange (ETDEWEB)
Hossen, M. A., E-mail: armanplasma@gmail.com; Mamun, A. A. [Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh)
2015-07-15
The quantum ion-acoustic (QIA) solitary and shock structures formed in a strongly coupled cryogenic quantum plasma (containing strongly coupled positively charged inertial cold ions and Fermi electrons as well as positrons) have been theoretically investigated. The generalized quantum hydrodynamic model and the reductive perturbation method have been employed to derive the Korteweg-de Vries (K-dV) and Burgers equations. The basic features of the QIA solitary and shock structures are identified by analyzing the stationary solitary and shock wave solutions of the K-dV and Burgers equations. It is found that the basic characteristics (e.g., phase speed, amplitude, and width) of the QIA solitary and shock structures are significantly modified by the effects of the Fermi pressures of electrons and positrons, the ratio of Fermi temperature of positrons to that of electrons, the ratio of effective ion temperature to electron Fermi temperature, etc. It is also observed that the effect of strong correlation among extremely cold ions acts as a source of dissipation, and is responsible for the formation of the QIA shock structures. The results of this theoretical investigation should be useful for understanding the nonlinear features of the localized electrostatic disturbances in laboratory electron-positron-ion plasmas (viz., super-intense laser-dense matter experiments)
Solitary Tibial Osteolytic Lesion
Directory of Open Access Journals (Sweden)
Emilios E. Pakos
2009-01-01
Full Text Available We report an unusual case of solitary osteolytic tibial metastasis from a primary endometrial cancer in a 62-year-old woman. The primary cancer was treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy combined with postoperative external beam radiotherapy, while the tibial metastasis was treated with an above knee amputation. The rarity of the case lies on the fact that metastases distally to the elbow and knee are uncommon and endometrial cancer rarely gives distal bone metastases and particularly solitary to the extremities.
Ion-acoustic solitons, double layers and rogue waves in plasma having superthermal electrons
Singh Saini, Nareshpal
2016-07-01
Most of the space and astrophysical plasmas contain different type of charged particles with non-Maxwellian velocity distributions (e.g., nonthermal, superthermal, Tsallis ). These distributions are commonly found in the auroral region of the Earth's magnetosphere, planetary magnetosphere, solar and stellar coronas, solar wind, etc. The observations from various satellite missions have confirmed the presence of superthermal particles in space and astrophysical environments. Over the last many years, there have been a much interest in studying the different kind of properties of the electrostatic nonlinear excitations (solitons, double layers, rogue waves etc.) in a multi-component plasmas in the presence of superthermal particles. It has been analyzed that superthermal distributions are more appropriate than Maxwellian distribution for the modeling of space data. It is interesting to study the dynamics of various kinds of solitary waves, Double layers, Shocks etc. in varieties of plasma systems containing different kind of species obeying Lorentzian (kappa-type)/Tsallis distribution. In this talk, I have focused on the study of large amplitude IA solitary structures (bipolar solitary structures, double layers etc.), modulational instability and rogue waves in multicomponent plasmas. The Sagdeev potential method has been employed to setup an energy balance equation, from which we have studied the characteristics of large amplitude solitary waves under the influence of superthermality of charged particles and other plasma parameters. The critical Mach number has been determined, above which solitary structures are observed and its variation with superthermality of electrons and other parameters has also been discussed. Double layers have also been discussed. Multiple scale reductive perturbation method has been employed to derive NLS equation. From the different kind of solutions of this equation, amplitude modulation of envelope solitons and rogue waves have been
M, G. Hafez; N, C. Roy; M, R. Talukder; M Hossain, Ali
2017-01-01
A comparative study is carried out for the nonlinear propagation of ion acoustic shock waves both for the weakly and highly relativistic plasmas consisting of relativistic ions and q-distributed electrons and positions. The Burgers equation is derived to reveal the physical phenomena using the well known reductive perturbation technique. The integration of the Burgers equation is performed by the (G\\prime /G)-expansion method. The effects of positron concentration, ion–electron temperature ratio, electron–positron temperature ratio, ion viscosity coefficient, relativistic streaming factor and the strength of the electron and positron nonextensivity on the nonlinear propagation of ion acoustic shock and periodic waves are presented graphically and the relevant physical explanations are provided.
Energy Technology Data Exchange (ETDEWEB)
Mead, W.C.
1980-09-11
Ion acoustic turbulence is examined as one mechanism which could contribute to the inhibition of electron thermal transport which has been inferred from many laser-plasma experiments. The behavior of the ion acoustic instability is discussed from the viewpoint of the literature of 2-dimensional particle-in-cell simulations. Simulation techniques, limitations, and reported saturation mechanisms and levels are discussed. A scaling law for the effective collision frequency ..nu..* can be fit to several workers' results to within an order-of-magnitude. The inferred ..nu..* is shown to be 1-2 orders-of-magnitude too small to account for the transport inhibition seen in Nd-laser-produced plasmas. Several differences between the simulation conditions and laser-produced plasma conditions are noted.
Energy Technology Data Exchange (ETDEWEB)
Wahlund, J.E.; Opgenoorth, H.J.; Persson, M.A.L. (Swedish Institute of Space Physics, Uppsala (Sweden)); Mishin, E.V.; Volokitin, A.S. (IZMIRAN, Troitsk, Moscow Region (Russian Federation)); Forme, F.R.E. (CNRS/CRPE (France))
1992-10-02
The authors propose an explanation for ion acoustic line spectra which have been observed by the EISCAT and Millstone Hill radars in the topside auroral ionosphere. They show that such lines can be generated in plasmas which are unstable to the ion-ion two-stream instability. This mechanism has the advantage of explaining the observed phenomena, and being consistent with typical conditions in the topside ionosphere.
Enhanced ion acoustic lines due to strong ion cyclotron wave fields
Directory of Open Access Journals (Sweden)
H. Bahcivan
2008-07-01
Full Text Available The Fast Auroral Snapshot Explorer (FAST satellite detected intense and coherent 5–20 m electric field structures in the high-latitude topside auroral ionosphere between the altitudes of 350 km and 650 km. These electric fields appear to belong to electrostatic ion cyclotron (EIC waves in terms of their frequency and wavelengths. Numerical simulations of the response of an electron plasma to the parallel components of these fields show that the waves are likely to excite a wave-driven parallel ion acoustic (IA instability, through the creation of a highly non-Maxwellian electron distribution function, which when combined with the (assumed Maxwellian ion distribution function provides inverse Landau damping. Because the counter-streaming threshold for excitation of EIC waves is well below that for excitation of IA waves (assuming Maxwellian statistics our results suggest a possible two step mechanism for destabilization of IA waves. Combining this simulation result with the observational fact that these EIC waves share a common phenomenology with the naturally enhanced IA lines (NEIALS observed by incoherent scatter radars, especially that they both occur near field-aligned currents, leads to the proposition that this two-step mechanism is an alternative path to NEIALS.
Ion-acoustic double layers in magnetized positive-negative ion plasmas with nonthermal electrons
El-Labany, S. K.; Sabry, R.; El-Taibany, W. F.; Elghmaz, E. A.
2012-07-01
The nonlinear ion-acoustic double layers (IADLs) in a warm magnetoplasma with positive-negative ions and nonthermal electrons are investigated. For this purpose, the hydrodynamic equations for the positive-negative ions, nonthermal electron density distribution, and the Poisson equation are used to derive a modified Zakharov-Kuznetsov (MZK) equation, in the small amplitude regime. It is found that compressive and rarefactive IADLs strongly depend on the mass and density ratios of the negative-to-positive ions as well as the nonthermal electron parameter. Also, it is shown that there are one critical value for the density ratio of the negative-to-positive ions ( ν), the ratio between unperturbed electron-to-positive ion density ( μ), and the nonthermal electron parameter ( β), which decide the existence of positive and negative IADLs. The present study is applied to examine the small amplitude nonlinear IADL excitations for the (H+, O2-) and (H+,H-) plasmas, where they are found in the D- and F-regions of the Earth's ionosphere. This investigation should be helpful in understanding the salient features of the nonlinear IADLs in either space or laboratory plasmas where two distinct groups of ions and non-Boltzmann distributed electrons are present.
Ion-acoustic Shocks with Self-Regulated Ion Reflection and Acceleration
Malkov, M A; Dudnikova, G I; Liseykina, T V; Diamond, P H; Papadopoulos, K; Liu, C-S; Su, J-J
2015-01-01
An analytic solution describing an ion-acoustic collisionless shock, self-consistently with the evolution of shock-reflected ions, is obtained. The solution extends the classic soliton solution beyond a critical Mach number, where the soliton ceases to exist because of the upstream ion reflection. The reflection transforms the soliton into a shock with a trailing wave and a foot populated by the reflected ions. The solution relates parameters of the entire shock structure, such as the maximum and minimum of the potential in the trailing wave, the height of the foot, as well as the shock Mach number, to the number of reflected ions. This relation is resolvable for any given distribution of the upstream ions. In this paper, we have resolved it for a simple "box" distribution. Two separate models of electron interaction with the shock are considered. The first model corresponds to the standard Boltzmannian electron distribution in which case the critical shock Mach number only insignificantly increases from M=1....
Ion-acoustic shocks with self-regulated ion reflection and acceleration
Malkov, M. A.; Sagdeev, R. Z.; Dudnikova, G. I.; Liseykina, T. V.; Diamond, P. H.; Papadopoulos, K.; Liu, C.-S.; Su, J. J.
2016-04-01
An analytic solution describing an ion-acoustic collisionless shock, self-consistently with the evolution of shock-reflected ions, is obtained. The solution extends the classic soliton solution beyond a critical Mach number, where the soliton ceases to exist because of the upstream ion reflection. The reflection transforms the soliton into a shock with a trailing wave and a foot populated by the reflected ions. The solution relates parameters of the entire shock structure, such as the maximum and minimum of the potential in the trailing wave, the height of the foot, as well as the shock Mach number, to the number of reflected ions. This relation is resolvable for any given distribution of the upstream ions. In this paper, we have resolved it for a simple "box" distribution. Two separate models of electron interaction with the shock are considered. The first model corresponds to the standard Boltzmannian electron distribution in which case the critical shock Mach number only insignificantly increases from M ≈1.6 (no ion reflection) to M ≈1.8 (substantial reflection). The second model corresponds to adiabatically trapped electrons. They produce a stronger increase, from M ≈3.1 to M ≈4.5 . The shock foot that is supported by the reflected ions also accelerates them somewhat further. A self-similar foot expansion into the upstream medium is described analytically.
Oblique ion-acoustic cnoidal waves in two temperature superthermal electrons magnetized plasma
Energy Technology Data Exchange (ETDEWEB)
Panwar, A., E-mail: anurajrajput@gmail.com; Ryu, C. M., E-mail: ryu201@postech.ac.kr [POSTECH, Hyoja-Dong San 31, KyungBuk, Pohang 790-784 (Korea, Republic of); Bains, A. S., E-mail: bainsphysics@yahoo.co.in [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Shandong University at Weihai, 264209 Weihai (China)
2014-12-15
A study is presented for the oblique propagation of ion acoustic cnoidal waves in a magnetized plasma consisting of cold ions and two temperature superthermal electrons modelled by kappa-type distributions. Using the reductive perturbation method, the nonlinear Korteweg de-Vries equation is derived, which further gives the solutions with a special type of cnoidal elliptical functions. Both compressive and rarefactive structures are found for these cnoidal waves. Nonlinear periodic cnoidal waves are explained in terms of plasma parameters depicting the Sagdeev potential and the phase curves. It is found that the density ratio of hot electrons to ions μ significantly modifies compressive/refractive wave structures. Furthermore, the combined effects of superthermality of cold and hot electrons κ{sub c},κ{sub h}, cold to hot electron temperature ratio σ, angle of propagation and ion cyclotron frequency ω{sub ci} have been studied in detail to analyze the height and width of compressive/refractive cnoidal waves. The findings in the present study could have important implications in understanding the physics of electrostatic wave structures in the Saturn's magnetosphere where two temperature superthermal electrons are present.
Ion-acoustic rogue waves and breathers in relativistically degenerate electron-positron plasmas
Abdikian, A.; Ismaeel, S.
2017-08-01
In this paper, we employ a weakly relativistic fluid model to study the nonlinear amplitude modulation of electrostatic waves in an unmagnetized electron-positron-ion plasma. It is assumed that the degeneracy pressure law for electrons and positrons follows the Chandrasekhar limit of state whereas ions are warm and classical. The hydrodynamic approach along with the perturbation method have been applied to obtain the corresponding nonlinear Schrödinger equation (NLSE) in which nonlinearity is in balance with the dispersive terms. Using the NLSE, we could evaluate the modulational instability to show that various types of localized ion acoustic excitations exist in the form of either bright-type envelope solitons or dark-type envelope solitons. The regions of the stable and unstable envelope wave have been confined punctually for various regimes. Furthermore, it is proposed that the exact solutions of the NLSE for breather waves are the rogue waves (RWs), Akhmediev breather (AB), and Kuznetsov-Ma breather (KM) soliton. In order to show that the characteristics of breather structures is influenced by the plasma parameters (namely, relativistic parameter, positron concentration, and ionic temperature), the relevant numerical analysis of the NLSE is examined. In particular, it is observed that by increasing the values of the mentioned plasma parameters, the amplitude of the RWs will be decreased. Our results help researchers to explain the formation and dynamics of nonlinear electrostatic excitations in super dense astrophysical regimes.
Indian Academy of Sciences (India)
C S Jayasree; G Renuka; C Venugopal
2003-12-01
During the magnetic storm of 21st March 1990, the DE-1 spacecraft encountered the auroral region at high invariant latitude at altitudes ranging from a few thousand kilometers in the ionosphere to many earth radii in the magnetosphere. The magnetic field perturbations interpretable as field aligned current (FAC) layers and the electrostatic turbulence possibly due to electrostatic ion acoustic instability driven by these currents are shown. The critical drift velocity of Hot Plasma Torus (HPT) electrons and the growth rate of ion acoustic wave as a function of electron to ion temperature ratio (/) for low and high current densities and energy of HPT electrons are found out. The intense FAC destabilizes the ion acoustic wave and the resultant electrostatic turbulence creates an anomalous resistivity. The current driven resistivity produces parallel electric field and high power dissipation. The anomalous resistivity , potential differnece along the auroral field lines ∥, intensity of electric field turbulence ∥ and power produced per unit volume are computed. It is found that the change in westward magnetic perturbation increases ∥; ; ∥ ;∥ and . Hence HPT electrons are heated and accelerated due to power dissipation during magnetically active periods in the auroral region. Concerning, applications, such HPT electrons can be used in particle accelerators like electron ring accelerator, smokatron etc.
Energy Technology Data Exchange (ETDEWEB)
Nopoush, M.; Abbasi, H. [Faculty of Physics, Amirkabir University of Technology, P. O. Box 15875-4413, Tehran (Iran, Islamic Republic of)
2011-08-15
The present paper is devoted to the simulation of the nonlinear disintegration of a localized perturbation into an ion-acoustic soliton in a plasma. Recently, this problem was studied by a simple model [H. Abbasi et al., Plasma Phys. Controlled Fusion 50, 095007 (2008)]. The main assumptions were (i) in the electron velocity distribution function (DF), the ion-acoustic soliton velocity was neglected in comparison to the electron thermal velocity, (ii) on the ion-acoustic evolution time-scale, the electron velocity DF was assumed to be stationary, and (iii) the calculation was restricted to the small amplitude case. In order to generalize the model, one has to consider the evolution of the electron velocity DF for finite amplitudes. For this purpose, a one dimensional electrostatic hybrid code, particle in cell (PIC)-fluid, was designed. It simulates the electrons dynamics by the PIC method and the cold ions dynamics by the fluid equations. The plasma contains a population of super-thermal electrons and, therefore, a Lorentzian (kappa) velocity DF is used to model the high energy tail in the electron velocity DF. Electron trapping is included in the simulation in view of their nonlinear resonant interaction with the localized perturbation. A Gaussian initial perturbation is used to model the localized perturbation. The influence of both the trapped and the super-thermal electrons on this process is studied and compared with the previous model.
Solitary and freak waves in superthermal plasma with ion jet
Abdelsalam, U. M.; Abdelsalam
2013-06-01
The nonlinear solitary and freak waves in a plasma composed of positive and negative ions, superthermal electrons, ion beam, and stationary dust particles have been investigated. The reductive perturbation method is used to obtain the Korteweg-de Vries (KdV) equation describing the system. The latter admits solitary wave solution, while the dynamics of the modulationally unstable wavepackets described by the KdV equation gives rise to the formation of freak/rogue excitation described by the nonlinear Schrödinger equation. In order to show that the characteristics of solitary and freak waves are influenced by plasma parameters, relevant numerical analysis of appropriate nonlinear solutions are presented. The results from this work predict nonlinear excitations that may associate with ion jet and superthermal electrons in Herbig-Haro objects.
Ongerboer de Visser, B W; Moffie, D
1981-01-01
The available clinical and pathological data of 5 cases with solitary midbrain metastasis including 2 of the present study are reviewed. Progressive dementia occurred in one case and mild dementia in another who also developed ocular symptoms. Ocular symptoms with sensory and coordination disturbances were seen in one, and only ocular symptoms in another case. Right-sided hemiplegia of 5 years duration occurred in the remaining case. Survival in tegmentum lesions is short.
Solitary intraosseous neurofibroma of mandible.
Directory of Open Access Journals (Sweden)
Vivek N
2006-01-01
Full Text Available Solitary intraosseous neurofibroma is a rare benign non-odontogenic tumor. Although neurofibromas occur predominantly as a feature of neurofibromatosis affecting the soft tissue, a few cases of solitary intraosseous neurofibromas of the jaw have been reported. We herewith report a case of solitary intraosseous neurofibroma of mandible in a middle-aged woman with a discussion on its clinical, radiological, and histopathological presentation along with review of cases.
Naturally Enhanced Ion Acoustic Lines with the Poker Flat AMISR radar.
Stromme, A.; Semeter, J.; Zettergren, M.
2007-12-01
The study of Naturally Enhanced Ion Acoustic Lines (NEIALs) have become one of the key studies for EISCAT both in the polar cusp using the EISCAT Svalbard Radar (ESR), and in the auroral zone, using the EISCAT UHF and VHF systems. Still many questions regarding the temporal and spatial extent of the NEIAL events remain unanswered. The new Advanced Modular Incoherent Scatter Radar (AMISR) in Poker Flat, Alaska is the first phased array Incoherent Scatter Radar at high latitudes, and by taking advantage of its possibility of (almost) simultaneous looking directions, we can resolve some of the space time ambiguity associated with NEIALs. During the night of the 23. March 2007, a period of NEIALs occurred. The radar ran in a 10 position mode with 9 beams in a narrow quadratic grid spaced by 3 degrees, plus a 10th position up B - slightly offset from the grid. Raw voltage data were sampled to allow for very high time resolution ACFs and spectra. Combining high time resolution data from multiple positions, we have the opportunity for the first time to look at the space-time ambiguity in the development of NEIALs. During the campaign a narrow field of view imager from university of Boston were operational at the Davis science center close by the AMISR array. The night of the 23. March, the imager was pointed field aligned, and at around 11:20 UT - at the time of the radar NEIALs - a field of dynamic rays occurred at and near the zenith. High time resolution multi position data from AMISR will be shown to follow the space and time development of the NEIAL event. This will also be correlated with high time resolution data from the imager.
Aminmansoor, F.; Abbasi, H.
2015-08-01
The present paper is devoted to simulation of nonlinear disintegration of a localized perturbation into ion-acoustic solitons train in a plasma with hot electrons and cold ions. A Gaussian initial perturbation is used to model the localized perturbation. For this purpose, first, we reduce fluid system of equations to a Korteweg de-Vries equation by the following well-known assumptions. (i) On the ion-acoustic evolution time-scale, the electron velocity distribution function (EVDF) is assumed to be stationary. (ii) The calculation is restricted to small amplitude cases. Next, in order to generalize the model to finite amplitudes cases, the evolution of EVDF is included. To this end, a hybrid code is designed to simulate the case, in which electrons dynamics is governed by Vlasov equation, while cold ions dynamics is, like before, studied by the fluid equations. A comparison between the two models shows that although the fluid model is capable of demonstrating the general features of the process, to have a better insight into the relevant physics resulting from the evolution of EVDF, the use of kinetic treatment is of great importance.
Directory of Open Access Journals (Sweden)
Renu M Magdum
2014-01-01
Full Text Available Schwannomas are rare benign tumors arising from Schwann cells of peripheral nerves that form the neural sheath. While there have been reports of such tumors in the orbit, solitary schwannomas arising from the eyelids are very rare. There are reports of schwannomas being erroneously diagnosed as chalazion, inclusion cysts or even eyelid malignancy. We are reporting a case of a 20-year-old female who presented with a painless, non-tender, slow-growing mass in the upper eyelid of the right eye. The external appearance of the mass was suggestive of an implantation cyst of the eyelid and it could be completely excised as it had a well-defined capsule. Histopathological examination showed characteristic hypercellular and hypocellular areas with fusiform nuclei that tended to form palisades. The purpose of reporting this case of schwannoma in a young female is to recommend the inclusion of this entity as a differential diagnosis of well-defined lid tumors.
Solitary Polypoid Laryngeal Xanthoma
Directory of Open Access Journals (Sweden)
Francisco Vera-Sempere
2013-01-01
Full Text Available We report the case of a 51-year-old male smoker with diabetes mellitus and hyperlipidaemia and a long history of human immunodeficiency virus (HIV/hepatitis C virus (HCV infection treated with various antiretroviral regimes, who was referred to the otolaryngology department with progressive dysphonia. Fibre-optic laryngoscopy showed a solitary, yellowish-white pedunculated polyp on the anterior third of the left cord, with no other abnormality. Pathological analysis revealed a polypoid laryngeal xanthoma that was immunoreactive against CD68, perilipin, and adipophilin. This unusual laryngeal lesion in the clinical context of our patient suggests a possible role of antiretroviral treatment in the pathogenesis of these xanthomas.
Directory of Open Access Journals (Sweden)
Manlio Mencoboni
2010-12-01
Full Text Available Solitary fibrous tumor (SFT is a rare mesenchymal neoplasm which may be found everywhere in the body. It is now distinguished into two forms, pleural and extrapleural, which morphologically resemble each other. Abdominal localizations are quite rare, with 10 cases only reported in bladder; rarely they can be source of paraneoplastic syndromes (i.e., hypoglycemia secondary to insulin-like growth factor. In April 2006 a 74-year-old white male presented with chills, diaphoresis and acute abdominal pain with hematuria. At admission in emergency he underwent an abdominal X-ray (no pathological findings and an ultrasound examination of the kidneys and urinary tract, which revealed a pelvic hyperechogenic neoformation measuring approximately 10¥8¥7 cm, compressing the bladder. Blood chemistry at admission revealed only a mild neutrophilic leucocytosis (WBC 16600, N 80%, L 11%, elevated fibrinogen and ESR, and hypoglycemia (38 mg/dL. Macroscopic hematuria was evident, while urinocolture was negative. Contrast enhanced CT scan of the abdomen and pelvic region revealed a large round neoformation dislocating the bladder, with an evident contrast-enhanced periphery and a central necrotic area. Continuous infusion of glucose 5% solution was necessary in order to maintain blood glucose levels above 50 mg/dL. The patient underwent complete surgical resection of an ovoidal mass coated by adipose tissue, with well delimited margins; histological findings were consistent with solitary fibrous tumor (SFT. Hypoglycemia resolved completely with removal of the growth. In this case report we describe a SFT growing in the bladder, a quite rare localization, which presented a unique hypoglycemia. In contrast to the majority of cases reported in the literature, the behavior of this SFT was not aggressive, and, since the patient is still alive, surgical resection was considered conclusive.
Lee, Myoung-Jae; Jung, Young-Dae
2017-04-01
The influence of electron–electron collisions on the propagation of the ion-acoustic space-charge wave is investigated in a cylindrical waveguide filled with warm collisional plasma by employing the normal mode analysis and the method of separation of variables. It is shown that the frequency of the ion-acoustic space-charge wave with higher-harmonic modes is always smaller than that with lower-harmonic modes, especially in intermediate wave number domains. It is also shown that the collisional damping rate of the ion-acoustic space-charge wave due to the electron–electron collision effect with higher-harmonic modes is smaller than that with lower-harmonic modes. In addition, it is found that the maximum position of the collisional damping rate shifts to large wave numbers with an increase of the harmonic mode. The variation of the wave frequency and the collisional damping rate of the ion-acoustic space-charge wave is also discussed.
Energy Technology Data Exchange (ETDEWEB)
Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200 (South Africa); Bharuthram, R. [University of the Western Cape, Modderdam Road, Bellville 7530 (South Africa); Singh, S. V. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India); School of Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa); Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India)
2012-07-15
Using the Sagdeev pseudopotential technique, the existence of large amplitude ion-acoustic solitons is investigated for a plasma composed of ions, and hot and cool electrons. Not only are all species treated as adiabatic fluids but the model for which inertial effects of the hot electrons is neglected whilst retaining inertia and pressure for the ions and cool electrons has also been considered. The focus of this investigation has been on identifying the admissible Mach number ranges for large amplitude nonlinear ion-acoustic soliton structures. The lower Mach number limit yields a minimum velocity for the existence of ion-acoustic solitons. The upper Mach number limit for positive potential solitons is found to coincide with the limiting value of the potential (positive) beyond which the ion number density ceases to be real valued, and ion-acoustic solitons can no longer exist. Small amplitude solitons having negative potentials are found to be supported when the temperature of the cool electrons is negligible.
Energy Technology Data Exchange (ETDEWEB)
Bouzit, Omar, E-mail: omar.bouzit@yahoo.fr; Tribeche, Mouloud, E-mail: mouloudtribeche@yahoo.fr, E-mail: mtribeche@usthb.dz [Plasma Physics Group (PPG), Theoretical Physics Laboratory (TPL), Faculty of Physics, University of Bab-Ezzouar, U.S.T.H.B, B.P. 32, El Alia, Algiers 16111 (Algeria); Bains, A. S., E-mail: bainsphysics@yahoo.co.in [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N5E2 (Canada)
2015-08-15
Modulation instability of ion-acoustic waves (IAWs) is investigated in a collisionless unmagnetized one dimensional plasma, containing positive ions and electrons following the mixed nonextensive nonthermal distribution [Tribeche et al., Phys. Rev. E 85, 037401 (2012)]. Using the reductive perturbation technique, a nonlinear Schrödinger equation which governs the modulation instability of the IAWs is obtained. Valid range of plasma parameters has been fixed and their effects on the modulational instability discussed in detail. We find that the plasma supports both bright and dark solutions. The valid domain for the wave number k where instabilities set in varies with both nonextensive parameter q as well as non thermal parameter α. Moreover, the analysis is extended for the rational solutions of IAWs in the instability regime. Present study is useful for the understanding of IAWs in the region where such mixed distribution may exist.
Directory of Open Access Journals (Sweden)
Z Ebne Abbasi
2013-03-01
Full Text Available Investigation of ion acoustic solitons in three component plasma including positive and negative ions and Maxwellian electrons shows that negative to positive relative ion density plays a critical role so that by changing ν over the range of 0<ν<1 compressive or rarefactive solitons will propagate. In this paper, it is shown that due to the superthermal electrons, there are three domains for ν so that in the first one only compressive solitons are allowed, in the second one compressive and rarefactive solitons coexist together and in the third one only rarefactive solitons are observed. The results from sagdeev potential in weak nonlinear region are in good agreement with analytic results obtained from KdV equation.
Michael, Manesh; Venugopal, C.; Sreekala, G.; Willington, Neethu Theresa; Sebastian, Sijo
2016-07-01
We investigate the propagation characteristics of Ion-acoustic solitons and double layers in a five component cometary plasma consisting of positively and negatively charged oxygen ions, kappa described hydrogen ions, hot solar electrons, and slightly colder cometary electrons. The KdV and modified KdV equations are derived for the system and its solution is plotted for different kappa values and negatively charged oxygen ion densities. It is found that the strength of double layer increases with increasing spectral indices. It, however, decreases with increasing negatively charged oxygen ion densities. The parameter for the transition from compressive to rarefactive soliton is also specified. The presence of negatively charged oxygen ions can significantly affect the nonlinearity coefficients (both quadratic and cubic) of a double layer.
Energy Technology Data Exchange (ETDEWEB)
Rufai, O. R., E-mail: rrufai@csir.co.za [Council for Scientific and Industrial Research, Pretoria (South Africa); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Bellville (South Africa); Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (W), Navi, Mumbai-410218 (India)
2015-10-15
The effect of excess superthermal electrons is investigated on finite amplitude nonlinear ion-acoustic waves in a magnetized auroral plasma. The plasma model consists of a cold ion fluid, Boltzmann distribution of cool electrons, and kappa distributed hot electron species. The model predicts the evolution of negative potential solitons and supersolitons at subsonic Mach numbers region, whereas, in the case of Cairn's nonthermal distribution model for the hot electron species studied earlier, they can exist both in the subsonic and supersonic Mach number regimes. For the dayside auroral parameters, the model generates the super-acoustic electric field amplitude, speed, width, and pulse duration of about 18 mV/m, 25.4 km/s, 663 m, and 26 ms, respectively, which is in the range of the Viking spacecraft measurements.
Hafez, M. G.; Talukder, M. R.; Ali, M. Hossain
2016-01-01
The theoretical and numerical studies have been investigated on the nonlinear propagation of electrostatic ion-acoustic waves (IAWs) in an un-magnetized Thomas-Fermi plasma system consisting of electron, positrons, and positive ions for both of ultra-relativistic and non-relativistic degenerate electrons. Korteweg-de Vries (K-dV) equation is derived from the model equations by using the well-known reductive perturbation method. This equation is solved by employing the generalized Riccati equation mapping method. The hyperbolic functions type solutions to the K-dV equation are only considered for describing the effect of plasma parameters on the propagation of electrostatic IAWs for both of ultra-relativistic and non-relativistic degenerate electrons. The obtained results may be helpful in proper understanding the features of small but finite amplitude localized IAWs in degenerate plasmas and provide the mathematical foundation in plasma physics.
Energy Technology Data Exchange (ETDEWEB)
Rouhani, M. R.; Akbarian, A.; Mohammadi, Z. [Department of Physics, Alzahra University, P. O. Box 1993891176, Tehran (Iran, Islamic Republic of)
2013-08-15
The behavior of quantum dust ion acoustic soliton and shocks in a plasma including inertialess quantum electrons and positrons, classical cold ions, and stationary negative dust grains are studied, using arbitrary amplitude approach. The effect of dissipation due to viscosity of ions is taken into account. The numerical analysis of Sagdeev potential for small value of quantum diffraction parameter (H) shows that for chosen plasma, only compressive solitons can exist and the existence domain of this type of solitons is decreased by increasing dust density (d). Additionally, the possibility of propagation of both subsonic and supersonic compressive solitons is investigated. It is shown that there is a critical dust density above which only supersonic solitons are observed. Moreover, increasing d leads to a reduction in the existence domain of compressive solitons and the possibility of propagation of rarefactive soliton is provided. So, rarefactive solitons are observed only due to the presence of dust particles in this model quantum plasma. Furthermore, numerical solution of governed equations for arbitrary amplitude shock waves has been investigated. It is shown that only compressive large amplitude shocks can propagate. Finally, the effects of plasma parameters on these structures are investigated. This research will be helpful in understanding the properties of dense astrophysical (i.e., white dwarfs and neutron stars) and laboratory dusty plasmas.
Effect of non-maxwellians ions on dust acoustic dressed soliton
Amour, Rabia; Tribeche, Mouloud
2016-07-01
Dust is an ubiquitous component of space and astrophysical environments, occurring for example in planetary rings, comets and the Earth's ionosphere. Dusty plasmas are known to support a wide variety of ultra low-frequency wave modes. The most well studied of such modes are the so called dust-acoustic wave (DAW) and dust ion-acoustic wave (DIAW). The aim of this communication is to study a small-amplitude dust acoustic dressed solitons in a three component dusty plasma having electrons, suprathermal ions, and dust grains. We have then investigate the effect of ion suprathermality on small amplitude dust acoustic dressed wave and compared the result with the soliton's exact solution of the fourth order of pseudo-potential and K-dV soliton.
Solitary mastocytoma in an adult
Directory of Open Access Journals (Sweden)
Jain V
1997-01-01
Full Text Available A 24-year old female developed late onset solitary mastocytoma on the left forearm. She complained of intense pruritus off and on which was not associated with flushing of face and blister formation over the nodule. Darier′s sign was positive. Excisional biopsy was done and histopathology confirmed the diagnosis.
Solitary waves and homoclinic orbits
Energy Technology Data Exchange (ETDEWEB)
Balmforth, N.J.
1994-03-01
The notion that fluid motion often organizes itself into coherent structures has increasingly permeated modern fluid dynamics. Such localized objects appear in laminar flows and persist in turbulent states; from the water on windows on rainy days, to the circulations in planetary atmospheres. This review concerns solitary waves in fluids. More specifically, it centres around the mathematical description of solitary waves in a single spatial dimension. Moreover, it concentrates on strongly dissipative dynamics, rather than integrable systems like the KdV equation. One-dimensional solitary waves, or pulses and fronts as they are also called, are the simplest kinds of coherent structure (at least from a geometrical point of view). Nevertheless, their dynamics can be rich and complicated. In some circumstances this leads to the formation of spatio-temporal chaos in the systems giving birth to the solitary waves, and understanding that phenomenon is one of the major goals in the theory outlined in this review. Unfortunately, such a goal is far from achieved to date, and the author assess its current status and incompleteness.
Perron, P. J. G.; J.-M. A. Noël; Kabin, K.; St-Maurice, J.-P.
2013-01-01
Temperature anisotropies may be encountered in space plasmas when there is a preferred direction, for instance, a strong magnetic or electric field. In this paper, we study how ion temperature anisotropy can affect the threshold conditions of a shear-modified current driven electrostatic ion-acoustic (CDEIA) instability. In particular, this communication focuses on instabilities in the context of topside auroral F-region situations and in the limit where finite Larmor radius...
Rehman, Momin A.; Mishra, M. K.
2016-01-01
The ion-acoustic solitons in collisionless plasma consisting of warm adiabatic ions, isothermal positrons, and two temperature distribution of electrons have been studied. Using reductive perturbation method, Korteweg-de Vries (K-dV), the modified K-dV (m-KdV), and Gardner equations are derived for the system. The soliton solution of the Gardner equation is discussed in detail. It is found that for a given set of parameter values, there exists a critical value of β=Tc/Th, (ratio of cold to hot electron temperature) below which only rarefactive KdV solitons exist and above it compressive KdV solitons exist. At the critical value of β, both compressive and rarefactive m-KdV solitons co-exist. We have also investigated the soliton in the parametric regime where the KdV equation is not valid to study soliton solution. In this region, it is found that below the critical concentration the system supports rarefactive Gardner solitons and above it compressive Gardner solitons are found. The effects of temperature ratio of two-electron species, cold electron concentration, positron concentration on the characteristics of solitons are also discussed.
Feng, Q S; Wang, Q; Zheng, C Y; Liu, Z J; Cao, L H; He, X T
2016-01-01
The properties of the nonlinear frequency shift (NFS) especially the fluid NFS from the harmonic generation of the ion-acoustic wave (IAW) in multi-ion species plasmas have been researched by Vlasov simulation. The pictures of the nonlinear frequency shift from harmonic generation and particles trapping are shown to explain the mechanism of NFS qualitatively. The theoretical model of the fluid NFS from harmonic generation in multi-ion species plasmas is given and the results of Vlasov simulation are consistent to the theoretical result of multi-ion species plasmas. When the wave number $k\\lambda_{De}$ is small, such as $k\\lambda_{De}=0.1$, the fluid NFS dominates in the total NFS and will reach as large as nearly $15\\%$ when the wave amplitude $|e\\phi/T_e|\\sim0.1$, which indicates that in the condition of small $k\\lambda_{De}$, the fluid NFS dominates in the saturation of stimulated Brillouin scattering especially when the nonlinear IAW amplitude is large.
Hafez, M. G.; Roy, N. C.; Talukder, M. R.; Hossain Ali, M.
2016-09-01
This work investigates the oblique nonlinear propagation of ion acoustic (IA) shock waves for both weakly and highly relativistic plasmas composed of nonthermal electrons and positrons with relativistic thermal ions. The KdVB-like equation, involving dispersive, weakly transverse dispersive, nonlinearity and dissipative coefficients, is derived employing the well known reductive perturbation method. The integration of this equation is carried out by the {tanh} method taking the stable shock formation condition into account. The effects of nonthermal electrons and positrons, nonthermal electrons with isothermal positrons, isothermal electrons with nonthermal positrons, and isothermal electrons and positrons on oblique propagation of IA shock waves in weakly relativistic regime are described. Furthermore, the effects of plasma parameters on oblique propagation of IA shock waves in highly relativistic regime are discussed and compared with weakly relativistic case. It is seen that the plasma parameters within certain limits significantly modify the structures of the IA shock waves in both cases. The results may be useful for better understanding of the interactions of charged particles with extra-galactic jets as well as astrophysical compact objects.
Energy Technology Data Exchange (ETDEWEB)
Gogoi, R; Kalita, L; Devi, N, E-mail: runmoni_gogoi@rediffmail.co, E-mail: latikakalita@rediffmail.co, E-mail: nirupama_cotton@rediffmail.co [Department of Mathematics, Cotton College, Guwahati-781001, Assam (India)
2010-02-01
Much interest was shown towards the studies on nonlinear stability in the late sixties. Plasma instabilities play an important role in plasma dynamics. More attention has been given towards stability analysis after recognizing that they are one of the principal obstacles in the way of a successful resolution of the problem of controlled thermonuclear fusion. Nonlinearity and dispersion are the two important characteristics of plasma instabilities. Instabilities and nonlinearity are the two important and interrelated terms. In our present work, the continuity and momentum equations for both ions and electrons together with the Poisson equation are considered as cold plasma model. Then we have adopted the modified reductive perturbation technique (MRPT) from Demiray [1] to derive the higher order equation of the Nonlinear Schroedinger equation (NLSE). In this work, detailed mathematical expressions and calculations are done to investigate the changing character of the modulation of ion acoustic plasma wave through our derived equation. Thus we have extended the application of MRPT to derive the higher order equation. Both progressive wave solutions as well as steady state solutions are derived and they are plotted for different plasma parameters to observe dark/bright solitons. Interesting structures are found to exist for different plasma parameters.
Impact of Ion Acoustic Wave Instabilities in the Flow Field of a Hypersonic Vehicle on EM Signals
Mudaliar, Saba; Sotnikov, Vladimir
2016-10-01
Flow associated with a high speed air vehicle (HSAV) can get partially ionized. In the absence of external magnetic field the flow field turbulence is due to ion acoustic wave (IAW) instabilities. Our interest is in studying the impact of this turbulence on the radiation characteristics of EM signals from the HSAV. We decompose the radiated signal into coherent and diffuse parts. We find that the coherent part has the same spectrum as that of the source signal, but it is distorted because of dispersive coherent attenuation. The diffuse part is expressed as a convolution (in wavenumber and frequency) of the source signal with the spectrum of electron density fluctuations. This is a constrained convolution in the sense that the spectrum has to satisfy the IAW dispersion relation. A quantity that characterizes the flow is the mean free path (MFP). When the MFP is large compared to the thickness of the flow the coherent part is significant. If the MFP is larger than the thickness of the flow the diffuse part is the dominant part of the received signal. In the special case when the source signal frequency is close the electron plasma frequency, there can exist in the flow region Langmuir modes in addition to the EM modes. The radiation characteristics of EM source signals from the HSAV in this case are quite different.
Directory of Open Access Journals (Sweden)
P. J. G. Perron
2013-03-01
Full Text Available Temperature anisotropies may be encountered in space plasmas when there is a preferred direction, for instance, a strong magnetic or electric field. In this paper, we study how ion temperature anisotropy can affect the threshold conditions of a shear-modified current driven electrostatic ion-acoustic (CDEIA instability. In particular, this communication focuses on instabilities in the context of topside auroral F-region situations and in the limit where finite Larmor radius corrections are small. We derived a new fluid-like expression for the critical drift which depends explicitly on ion anisotropy. More importantly, for ion to electron temperature ratios typical of F-region, solutions of the kinetic dispersion relation show that ion temperature anisotropy may significantly lower the drift threshold required for instability. In some cases, a perpendicular to parallel ion temperature ratio of 2 and may reduce the relative drift required for the onset of instability by a factor of approximately 30, assuming the ion-acoustic speed of the medium remains constant. Therefore, the ion temperature anisotropy should be considered in future studies of ion-acoustic waves and instabilities in the high-latitude ionospheric F-region.
Modeling of Plasma Irregularities in Expanding Ionospheric Dust Clouds
Fu, H.; Scales, W.; Mahmoudian, A.; Bordikar, M. R.
2009-12-01
Natural dust layers occur in the earth’s mesosphere (50km-85km). Plasma irregularities are associated with these natural dust layers that produce radar echoes. Recently, an Ionospheric sounding rocket experiment was performed to investigate the plasma irregularities in upper atmospheric dust layers. The Charged Aerosol Release Experiment (CARE) uses a rocket payload injection of particles in the ionosphere to determine the mechanisms for enhanced radar scatter from plasma irregularities embedded in artificial dusty plasma in space. A 2-D hybrid computational model is described that may be used to study a variety of irregularities in dusty space plasmas which may lead to radar echoes. In this model, the dust and ions are both treated with Particle-In-Cell method while the dust charge varies with time based on the standard dust Orbit Motion Limited charging model. A stochastic model is adopted to remove particle ions due to the dust charging process. Electrons are treated with a fluid model including the parallel dynamics of magnetic fields. Fourier spectral methods with a predictor-corrector time advance are used to solve it. This numerical model will be used to investigate the electrodynamics and several possible plasma irregularity generation mechanisms after the creation of an artificial dust layer. The first is the dust ion-acoustic instability due to the drift of dust relative to the plasma. The instability saturates by trapping some ions. The effects of dust radius and dust drift velocity on plasma irregularities will be analyzed further. Also, a shear- driven instability in expanding dusty clouds is investigated.
Solitary angiokeratoma of the tongue.
Sion-Vardy, Netta; Manor, Esther; Puterman, Max; Bodner, Lipa
2008-01-01
Angiokeratoma is a rare cutaneous lesion. It can be either a generalized systemic form, presenting as multiple asymptomatic papules on the skin, associated with metabolic diseases or a solitary cutaneous form. Oral cavity involvement is more common in the systemic form, as a part of a more generalized cutaneous disease, but very rare in the localized form of angiokeratoma. A 45-year-old female presented with a painless lesion on the tongue of one months duration, which bled occasionally. On clinical examination, a lesion of approximately 5 mm in diameter was observed on the left surface of the tongue. The lesion was purple in color with a granulomatous appearance. There were no other changes in the oral mucosa. On dermatologic examination, no angiokeratomas were found, anywhere on the skin. The lesion was excised under local anesthesia. The histologic diagnosis was angiokeratoma. A case of a solitary angiokeratoma of the tongue is reported. We report here the third intra-oral case and the second case in the tongue with solitary angiokeratoma.
Multi-component optical solitary waves
DEFF Research Database (Denmark)
Kivshar, Y. S.; Sukhorukov, A. A.; Ostrovskaya, E. A.
2000-01-01
We discuss several novel types of multi-component (temporal and spatial) envelope solitary waves that appear in fiber and waveguide nonlinear optics. In particular, we describe multi-channel solitary waves in bit-parallel-wavelength fiber transmission systems for highperformance computer networks......, multi-color parametric spatial solitary waves due to cascaded nonlinearities of quadratic materials, and quasiperiodic envelope solitons due to quasi-phase-matching in Fibonacci optical superlattices. (C) 2000 Elsevier Science B.V. All rights reserved....
Trushnikov, D. N.; Mladenov, G. M.; Belenkiy, V. Ya.; Koleva, E. G.; Varushkin, S. V.
2014-04-01
Many papers have sought correlations between the parameters of secondary particles generated above the beam/work piece interaction zone, dynamics of processes in the keyhole, and technological processes. Low- and high-frequency oscillations of the current, collected by plasma have been observed above the welding zone during electron beam welding. Low-frequency oscillations of secondary signals are related to capillary instabilities of the keyhole, however; the physical mechanisms responsible for the high-frequency oscillations (>10 kHz) of the collected current are not fully understood. This paper shows that peak frequencies in the spectra of the collected high-frequency signal are dependent on the reciprocal distance between the welding zone and collector electrode. From the relationship between current harmonics frequency and distance of the collector/welding zone, it can be estimated that the draft velocity of electrons or phase velocity of excited waves is about 1600 m/s. The dispersion relation with the properties of ion-acoustic waves is related to electron temperature 10 000 K, ion temperature 2 400 K and plasma density 1016 m-3, which is analogues to the parameters of potential-relaxation instabilities, observed in similar conditions. The estimated critical density of the transported current for creating the anomalous resistance state of plasma is of the order of 3 A.m-2, i.e. 8 mA for a 3-10 cm2 collector electrode. Thus, it is assumed that the observed high-frequency oscillations of the current collected by the positive collector electrode are caused by relaxation processes in the plasma plume above the welding zone, and not a direct demonstration of oscillations in the keyhole.
Electro-acoustic solitary waves and double layers in a quantum plasma
Dip, P. R.; Hossen, M. A.; Salahuddin, M.; Mamun, A. A.
2017-02-01
A meticulous theoretical investigation has carried out to study the properties related to the higher-order nonlinearity of the electro-acoustic waves, specifically ion-acoustic (IA) waves in an unmagnetized, collisionless, quantum electron-positron-ion (EPI) plasma. The plasma system is supposed to be formed of positively charged inertial heavy ions, inertialess electrons and positrons. The reductive perturbation technique is employed to derive the modified Korteweg-de Vries (mK-dV) equation to analyze the solitary waves (SWs), and the standard Gardner (SG) equation to analyze the higher-order SWs as well as double layers (DLs). The basic features (viz. amplitude, width, phase speed, etc.) of the IA SWs and DLs are examined. The comparison between the mK-dV SWs and SG SWs is also made. It is found that the amplitude, width, phase speed, etc. of the IA SWs and DLs are significantly modified by the effects of the both Fermi temperatures as well as pressures and Bohm potentials of electrons and positrons. Our findings may be useful in explaining the physics behind the formation of the IA waves in both astrophysical and laboratory EPI plasmas (viz. white dwarfs, laser-solid matter interaction experiments, etc.).
Charged dust and shock phenomena in the Solar System
Directory of Open Access Journals (Sweden)
S. I. Popel
2006-01-01
Full Text Available The results on shock phenomena in dusty plasmas of the Solar System are reviewed. The problems of dust ion acoustic bow shock in interaction of the solar wind with dusty cometary coma and formation of transient atmospheres of atmosphereless cosmic bodies such as Moon, Mercury, asteroids and comets are considered. The latter assumes the evolution of meteoroid impact plumes and production of charged dust grains due to the condensation of both the plume substance and the vapor thrown from the crater and the surrounding regolith layer. Physical phenomena occurring during large meteoroid impacts can be modeled with the aid of active rocket experiments, which involve the release of some gaseous substance in near-Earth space. New vistas in investigation of shock processes in natural dusty plasmas are determined.
[Solitary plasmocytoma of the mandible].
Laurent, F; Chausse, J M; Toccanier, M F; Kuffer, R
1985-01-01
The authors present a case of solitary bony plasmocytoma of the mandibule, with local amyloid deposition. Diagnosis was made at extemporaneous pathological examination, then confirmed by the examination of the fixed surgical sample. Immunoenzymologically the proliferation proved to be monoclonal, with secretion of kappa light chain. The patient was treated by surgical curettage and homologous cancelous bone filling, followed by 5,500 rads of electrontherapy. He was then regularly controlled during 8 years and remained free from local recurrence. All investigations in search of dissemination (Kahler disease) remained negative.
Solitary Fibrous Tumor of the Stomach
Hussain, Qulsoom; Shafique, Khurram; Hurairah, Abu; Grossman, Evan B.
2017-01-01
Solitary fibrous tumor is a rare mesenchymal neoplasm that usually originates from the pleura, but has been reported in other extrapleural locations. We report a rare case of a solitary fibrous tumor of the stomach, which was successfully treated with endoscopic mucosal resection. PMID:28286800
Solitary intraosseous neurofibroma of the tibia
Energy Technology Data Exchange (ETDEWEB)
Huang, Guo-Shu; Chang, Wei-Chou; Juan, Chun-Jung; Chen, Cheng-Yu. [National Defense Medical Center, Department of Radiology, Tri-Service General Hospital, Neihu 114, Taipei (Taiwan); Lee, Chian-Her [National Defense Medical Center, Department of Orthopedic Surgery, Tri-Service General Hospital, Neihu 114, Taipei (Taiwan); Lee, Herng-Sheng [National Defense Medical Center, Department of Pathology, Tri-Service General Hospital, Neihu 114, Taipei (Taiwan)
2005-05-01
A solitary intraosseous neurofibroma is rare and mostly occurs in the mandible. We report a case of a solitary intraosseous neurofibroma of the tibia. The radiographic findings were nonspecific and showed an eccentrically located, osteolytic lesion with a thin sclerotic border in the diaphysis of the left proximal tibia. The entity of intraosseous neurofibroma is briefly reviewed. (orig.)
Solitary Waves in Relativistic Electromagnetic Plasma
Institute of Scientific and Technical Information of China (English)
XIE Bai-Song; HUA Cun-Cai
2005-01-01
Solitary waves in relativistic electromagnetic plasmas are obtained numerically. The longitudinal momentum of electrons has been taken into account in the problem. It is found that in the moving frame with electromagnetic field propagating the solitary waves can exist in both cases, where the vector potential frequency is larger or smaller than the plasma characteristic frequency.
Haque, Q.; Mirza, Arshad M.; Iqbal, Javed
2016-04-01
Linear and nonlinear characteristics of electrostatic waves in a multicomponent magnetoplasma comprising of Boltzmann distributed electrons, Cairn's distributed hot electrons, and cold dynamic ions are studied. It is found that the effect of superthermal electrons, ion-neutral collisions, and ion shear flow modifies the propagation of ion-acoustic and drift waves. The growth rate of the ion shear flow instability varies with the addition of Cairn's distributed hot electrons. It is also investigated that the behavior of different type of vortices changes with the inclusion of superthermal hot electrons. The relevance of this investigation in space plasmas such as in auroral region and geomagnetic tail is also pointed out.
Electrostatic solitary waves in dusty pair-ion plasmas
Misra, A P
2013-01-01
The propagation of electrostatic waves in an unmagnetized collisionless pair-ion plasma with immobile positively charged dusts is studied for both large- and small-amplitude perturbations. Using a two-fluid model for pair-ions, it is shown that there appear two linear ion modes, namely the "fast" and "slow" waves in dusty pair-ion plasmas. The properties of these wave modes are studied with different mass $(m)$ and temperature $(T)$ ratios of negative to positive ions, as well as the effects of immobile charged dusts $(\\delta)$. For large-amplitude waves, the pseudopotential approach is performed, whereas the standard reductive perturbation technique (RPT) is used to study the small-amplitude Korteweg-de Vries (KdV) solitons. The profiles of the pseudopotential, the large amplitude solitons as well as the dynamical evolution of KdV solitons are numerically studied with the system parameters as above. It is found that the pair-ion plasmas with positively charged dusts support the propagation of solitary waves ...
Electrostatic solitary waves in dusty pair-ion plasmas
Energy Technology Data Exchange (ETDEWEB)
Misra, A. P. [Department of Mathematics, Siksha Bhavana, Visva-Bharati University, Santiniketan-731 235, West Bengal (India); Adhikary, N. C. [Physical Sciences Division, Institute of Advanced Study in Science and Technology, Vigyan Path, Paschim Boragaon, Garchuk, Guwahati-781035, Assam (India)
2013-10-15
The propagation of electrostatic waves in an unmagnetized collisionless pair-ion plasma with immobile positively charged dusts is studied for both large- and small-amplitude perturbations. Using a two-fluid model for pair-ions, it is shown that there appear two linear ion modes, namely the “fast” and “slow” waves in dusty pair-ion plasmas. The properties of these wave modes are studied with different mass (m) and temperature (T) ratios of negative to positive ions, as well as the effects of immobile charged dusts (δ). For large-amplitude waves, the pseudopotential approach is performed, whereas the standard reductive perturbation technique is used to study the small-amplitude Korteweg-de Vries (KdV) solitons. The profiles of the pseudopotential, the large amplitude solitons as well as the dynamical evolution of KdV solitons, are numerically studied with the system parameters as above. It is found that the pair-ion plasmas with positively charged dusts support the propagation of solitary waves (SWs) with only the negative potential. The results may be useful for the excitation of SWs in laboratory dusty pair-ion plasmas, electron-free industrial plasmas as well as for observation in space plasmas where electron density is negligibly small compared to that of negative ions.
Revisiting the plasma sheath - dust in plasma sheath
Das, G C; Bora, M P
2015-01-01
In this work, we have considered the formation of warm plasma sheath in the vicinity of a wall in a plasma with considerable presence of dust particles. As an example, we have used the parameters relevant in case of lunar plasma sheath, though the results obtained in this work could be applied to any other physical situation such as laboratory plasma. In the ion-acoustic time scale, we neglect the dust dynamics. The dust particles affect the sheath dynamics by affecting the Poisson equation which determines the plasma potential in the sheath region. We have assumed the current to a dust particle to be balanced throughout the analysis. This makes the grain potential dependent on plasma potential, which is then incorporated into the Poisson equation. The resultant numerical model becomes an initial value problem, which is described by a 1-D integro-differential equation, which is then solved self-consistently by incorporating the change in plasma potential caused by inclusion of the dust potential in the Poisso...
Charge Fluctuation of Dust Grain and Its Impact on Dusty-Acoustic Wave Damping
Atamaniuk, B
2007-01-01
We consider the influence of dust charge fluctuations on damping of the dust-ion-acoustic waves. It is assumed that all grains have equal masses but charges are not constant in time - they may fluctuate in time. The dust charges are not really independent of the variations in the plasma potentials. All modes will influence the charging mechanism, and feedback will lead to several new interesting and unexpected phenomena. The charging of the grains depends on local plasma characteristics. If the waves disturb these characteristic, then charging of the grains is affected and the grain charge is modified, with a resulting feedback on the wave mode. In the case considered here, when the temperature of electrons is much greater than the temperature of the ions and the temperature of electrons is not great enough for further ionization of the ions, we show that attenuation of the acoustic wave depends only on one phenomenological coefficient
Generalized polarization force acting on dust grains in a dusty plasma
Bentabet, Karima; Mayout, Saliha; Tribeche, Mouloud
2017-01-01
The polarization force acting on dust particles in a dusty plasma is revisited within the theoretical framework of the Tsallis statistical mechanics. The generalized nonextensive polarization force expression is derived. As application, the modifications arising in the propagation of dust-acoustic solitary waves, and dust sheath formation are analyzed. Our results should be of wide relevance to explain and interpret the sheath formation and its structure in nonequilibrium plasmas related process such as surface treatments and ion implantation.
Transversally periodic solitary gravity–capillary waves
Milewski, Paul A.; Wang, Zhan
2014-01-01
When both gravity and surface tension effects are present, surface solitary water waves are known to exist in both two- and three-dimensional infinitely deep fluids. We describe here solutions bridging these two cases: travelling waves which are localized in the propagation direction and periodic in the transverse direction. These transversally periodic gravity–capillary solitary waves are found to be of either elevation or depression type, tend to plane waves below a critical transverse period and tend to solitary lumps as the transverse period tends to infinity. The waves are found numerically in a Hamiltonian system for water waves simplified by a cubic truncation of the Dirichlet-to-Neumann operator. This approximation has been proved to be very accurate for both two- and three-dimensional computations of fully localized gravity–capillary solitary waves. The stability properties of these waves are then investigated via the time evolution of perturbed wave profiles. PMID:24399922
Solitary Fibrous Tumor of the Uterus
Directory of Open Access Journals (Sweden)
Po-Wei Chu
2006-12-01
Conclusion: The behavior of solitary fibrous tumors arising from the uterus is difficult to evaluate; therefore, complete surgical excision featuring clear margins and comprehensive follow-up is recommended.
Management of the Solitary Pulmonary Nodule.
Chan, Edward Y; Gaur, Puja; Ge, Yimin; Kopas, Lisa; Santacruz, Jose F; Gupta, Nakul; Munden, Reginald F; Cagle, Philip T; Kim, Min P
2016-09-02
Context .- Optimal management of the patient with a solitary pulmonary nodule entails early diagnosis and appropriate treatment for patients with malignant tumors, and minimization of unnecessary interventions and procedures for those with ultimately benign nodules. With the growing number of high-resolution imaging modalities and studies available, incidentally found solitary pulmonary nodules are an increasingly common occurrence. Objective .- To provide guidance to clinicians involved in the management of patients with a solitary pulmonary nodule, including aspects of risk stratification, workup, diagnosis, and management. Data Sources .- Data for this review were gathered from an extensive literature review on the topic. Conclusions .- Logical evaluation and management pathways for a patient with a solitary pulmonary nodule will allow providers to diagnose and treat individuals with early stage lung cancer and minimize morbidity from invasive procedures for patients with benign lesions.
Conservative numerical methods for solitary wave interactions
Energy Technology Data Exchange (ETDEWEB)
Duran, A; Lopez-Marcos, M A [Departamento de Matematica Aplicada y Computacion, Facultad de Ciencias, Universidad de Valladolid, Paseo del Prado de la Magdalena s/n, 47005 Valladolid (Spain)
2003-07-18
The purpose of this paper is to show the advantages that represent the use of numerical methods that preserve invariant quantities in the study of solitary wave interactions for the regularized long wave equation. It is shown that the so-called conservative methods are more appropriate to study the phenomenon and provide a dynamic point of view that allows us to estimate the changes in the parameters of the solitary waves after the collision.
Akbari-Moghanjoughi, M
2011-01-01
Recently, Yan-Xia Xu, et al. in the article Ref. [Phys. Plasmas \\textbf{18}, 052301 (2011)] have studied the effects of various plasma parameters on interaction of two ion-acoustic solitary waves in an unmagnetized three-dimensional electron-positron-ion quantum plasma. They have used the extended reductive perturbation technique, the so-called, extended Poincare'-Lighthill-Kuo (PLK) technique, to deduce from the model governing the quantum hydrodynamics (QHD) differential equations leading to the soliton dynamical properties, namely, Korteweg-de Vries evolution equations (one for each wave) and coupled differential equations describing the phase-shift in trajectories of solitons due to the two dimensional collision. The variation of the calculated collision phase-shifts are then numerically inspected in terms of numerous plasma fractional parameters. In this comment we give some notes specific to the validity of the results of above-mentioned article and refer to important misconceptions about the use of the...
EL-Kalaawy, O. H.
2017-03-01
The nonlinear propagation of modified ion acoustic shock waves and double layers in a relativistic degenerate plasma is considered. This plasma system is proposed for containing inertial viscous positive and negative ion fluids, relativistic electron fluids, and negatively charged immobile heavy ions. The basic set of fluid equations is reduced to modified Burgers (MB) and further modified Burgers (FMB) or (Gardner) or Mamun and Zobaer (M-Z) equations by using the reductive perturbation method. The basic features of these shocks obtained from this analysis are observed to be significantly different from those obtained from the standard Burgers equation. By introducing two special functions and He's semi-inverse method, a variational principle and conservation laws for the Gardner (FmB) equation are obtained. A set of new exact solutions for the Gardner (FmB) equation are obtained by the auto-Bäcklund transformations. Finally, we will study the physical meanings of solutions.
Afeyan, Bedros; Won, K; Montgomery, D S; Hammer, J; Kirkwood, R K; Schmitt, A J
2012-01-01
In a series of experiments on the Omega laser facility at LLE, we have demonstrated the suppression of SRS in prescribed spectral windows due to the presence of externally controlled levels of ion acoustic waves (IAW, by crossing two blue beams at the Mach -1 surface) and electron plasma waves (EPW, by crossing a blue and a green beam around a tenth critical density plasma) generated via optical mixing. We have further observed SRS backscattering of a green beam when crossed with a blue pump beam, in whose absence, that (green beam) backscattering signature was five times smaller. This is direct evidence for green beam amplification when crossed with the blue. Additional proof comes from transmitted green beam measurements. A combination of these techniques may allow the suppression of unacceptable levels of SRS near the light entrance hole of large-scale hohlraums on the NIF or LMJ.
Institute of Scientific and Technical Information of China (English)
刘铁路; 王云良; 路彦珍
2015-01-01
The nonlinear propagation of quantum ion acoustic wave (QIAW) is investigated in a four-component plasma com-posed of warm classical positive ions and negative ions, as well as inertialess relativistically degenerate electrons and positrons. A nonlinear Schr ¨odinger equation is derived by using the reductive perturbation method, which governs the dynamics of QIAW packets. The modulation instability analysis of QIAWs is considered based on the typical parameters of the white dwarf. The results exhibit that both in weakly relativistic limit and in ultrarelativistic limit, the modulational instability regions are sensitively dependent on the ratios of temperature and number density of negative ions to those of positive ions respectively, and on relativistically degenerate effect as well.
Colloidal solitary waves with temperature dependent compressibility
Azmi, A.; Marchant, T. R.
2014-05-01
Spatial solitary waves which form in colloidal suspensions of dielectric nanoparticles are considered. The interactions, or compressibility, of the colloidal particles, is modelled using a series in the particle density, or packing fraction, where the virial, or series, coefficients depend on the type of particle interaction model. Both the theoretical hard disk and sphere repulsive models, and a model with temperature dependent compressibility, are considered. Experimental results show that particle interactions can be temperature dependent and either repulsive or attractive in nature, so we model the second virial coefficient using a physically realistic temperature power law. One- and two-dimensional semi-analytical colloidal solitary wave solutions are found. Trial functions, based on the form of the nonlinear Schrödinger equation soliton, are used, together with averaging, to develop the semi-analytical solutions. When the background packing fraction is low, the one-dimensional solitary waves have three solutions branches (with a bistable regime) while the two-dimensional solitary waves have two solution branches, with a single stable branch. The temperature dependent second virial coefficient results in changes to the solitary wave properties and the parameter space, in which multiple solutions branches occur. An excellent comparison is found between the semi-analytical and numerical solutions.
Adjustable solitary waves in electroactive rods
Wang, Y. Z.; Zhang, C. L.; Dai, H.-H.; Chen, W. Q.
2015-10-01
This paper presents an asymptotic analysis of solitary waves propagating in an incompressible isotropic electroactive circular rod subjected to a biasing longitudinal electric displacement. Several asymptotic expansions are introduced to simplify the rod governing equations. The boundary conditions on the lateral surface of the rod are satisfied from the asymptotic point of view. In the limit of finite-small amplitude and long wavelength, a set of ten simplified one-dimensional nonlinear governing equations is established. To validate our approach and the derivation, we compare the linear dispersion relation with the one directly derived from the three-dimensional linear theory in the limit of long wavelength. Then, by the reductive perturbation method, we deduce the far-field equation (i.e. the KdV equation). Finally, the leading order of the electroelastic solitary wave solution is presented. Numerical examples are provided to show the influences of the biasing electric displacement and material constants on the solitary waves. It is found that the biasing electric displacement can modulate the velocity of solitary waves with a prescribed amplitude in the electroactive rod, a very interesting result which may promote the particular application of solitary waves in solids with multi-field coupling.
Solitary Spinal Epidural Metastasis from Gastric Cancer
Directory of Open Access Journals (Sweden)
Taisei Sako
2016-01-01
Full Text Available Solitary epidural space metastasis of a malignant tumor is rare. We encountered a 79-year-old male patient with solitary metastatic epidural tumor who developed paraplegia and dysuria. The patient had undergone total gastrectomy for gastric cancer followed by chemotherapy 8 months priorly. The whole body was examined for suspected metastatic spinal tumor, but no metastases of the spine or important organs were observed, and a solitary mass was present in the thoracic spinal epidural space. The mass was excised for diagnosis and treatment and was histopathologically diagnosed as metastasis from gastric cancer. No solitary metastatic epidural tumor from gastric cancer has been reported in English. Among the Japanese, 3 cases have been reported, in which the outcome was poor in all cases and no definite diagnosis could be made before surgery in any case. Our patient developed concomitant pneumonia after surgery and died shortly after the surgery. When a patient has a past medical history of malignant tumor, the possibility of a solitary metastatic tumor in the epidural space should be considered.
Reactive airway disease - dust; Bronchial asthma - dust; Triggers - dust ... Things that make allergies or asthma worse are called triggers. Dust is a common trigger. When your asthma or allergies become worse due to dust, you are ...
Intraoral solitary neurofibroma in an infant
Directory of Open Access Journals (Sweden)
Narwal Anjali
2008-01-01
Full Text Available Neurofibroma is a non-circumscribed, thick and irregular benign tumor of the peripheral nerve sheath. On the skin, the diffuse and soft nature of neurofibroma often resembles "a bag of worms". It can develop at any point along a nerve and often form by late adolescence. Although neurofibromas occur predominantly as a feature of neurofibromatosis affecting the soft tissue, a few cases of solitary intraoral neurofibromas have also been reported. Solitary intraosseous neurofibroma in the oral cavity is a rare benign tumor with very few cases reported in literature. This case report presents a case of intraosseous solitary neurofibroma of maxilla in a 5-month-old male child due to the rarity of this tumor at this site in very early age, along with a discussion of its clinical, radiological, and histopathological presentation.
A radiographic study of solitary bone cysts
Energy Technology Data Exchange (ETDEWEB)
Kim, Kyung Rak; Hwang, Eui Hwan; Lee, Sang Rae [Dept. of Oral and Maxillofacial Radiology, Division of Dentistry, Kyung Hee University, Seoul (Korea, Republic of)
1994-02-15
The aim of this study was to evaluate the clinical, radiographic and histopathologic features of 23 cases of solitary bone cyst by means of the analysis of radiographs and biopsy specimens in 23 persons visited the Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University and Chunbuk National University. The obtained results were as follows; 1. The incidence of solitary bone cyst was almost equal in males (52.2%) and in females(42.8%) and the prevalent age of the solitary bone cyst were the second decade (47.8%) and the third decade (21.7%). 2. In the signs and symptoms of solitary bone cyst, pain or tenderness revealed in 17.4%, swelling revealed in 13.0%, pain and swelling revealed in 21.7%, paresthesia revealed in 4.4% and 43.5% were a symptom and the tooth vitality involved in the solitary bone cyst, 76.5% were posterior and 23.5% were either positive or negative. 3. In the location of the solitary bone cyst, 47.8% present posterior region, 21.7% present anterior region, 21.6% present anterior and posterior region, 4.4% present condylar process area. 4. In the hyperostotic border of the solitary bone cyst, 47.8% were seen entirely, 21.8% were seen partially, and 30.4% were not seen. 5. In the change of tooth, 59.1% were loss of the alveolar lamina dura, 13.6% were root resorption 4.55% were tooth displacement, 4.55% were root resorption and tooth displacement. 6. In the change of cortical bone of the solitary bone cyst, 39.1% were intact and 60.9% were thinning and expansion of cortical bone. 7. In the histopathologic findings of 9 cases, 33.3% were thin connective tissue wall, 11.1% were thickened myxo-fibromatous wall, 55.6% were thickened myxofibromatous wall with dysplastic bone formation.
Uphill solitary waves in granular flows
Martínez, E.; Pérez-Penichet, C.; Sotolongo-Costa, O.; Ramos, O.; Måløy, K. J.; Douady, S.; Altshuler, E.
2007-03-01
We have experimentally observed uphill solitary waves in the surface flow on a granular material. A heap is constructed by injecting sand between two vertical glass plates separated by a distance much larger than the average grain size, with an open boundary. As the heap reaches the open boundary, solitary fluctuations appear on the flowing layer and move “up the hill” (i.e., against the direction of the flow). We explain the phenomenon in the context of stop-and-go traffic models.
Indian Academy of Sciences (India)
Aiyong Chen; Jibin Li; Chunhai Li; Yuanduo Zhang
2010-01-01
The bifurcation theory of dynamical systems is applied to an integrable non-linear wave equation. As a result, it is pointed out that the solitary waves of this equation evolve from bell-shaped solitary waves to W/M-shaped solitary waves when wave speed passes certain critical wave speed. Under different parameter conditions, all exact explicit parametric representations of solitary wave solutions are obtained.
The solitary sellar plasmacytoma: a diagnostic challenge
DEFF Research Database (Denmark)
Soejbjerg, Anne; Dyve, Suzan; Baerentzen, Steen
2016-01-01
UNLABELLED: Solitary sellar plasmacytomas are exceedingly rare and difficult to distinguish from other pituitary tumors. We report a case of a 62-year-old woman presenting with blurred vision of the right eye and tenderness of the right temporal region, which was interpreted as temporal arteritis...
Clinical implications of the solitary functioning kidney
Westland, R.; Schreuder, M.F.; Goudoever, J.B. van; Sanna-Cherchi, S.; Wijk, J.A. van
2014-01-01
Congenital anomalies of the kidney and urinary tract are the major cause of ESRD in childhood. Children with a solitary functioning kidney form an important subgroup of congenital anomalies of the kidney and urinary tract patients, and a significant fraction of these children is at risk for progress
Solitary waves on nonlinear elastic rods. I
DEFF Research Database (Denmark)
Sørensen, Mads Peter; Christiansen, Peter Leth; Lomdahl, P. S.
1984-01-01
Acoustic waves on elastic rods with circular cross section are governed by improved Boussinesq equations when transverse motion and nonlinearity in the elastic medium are taken into account. Solitary wave solutions to these equations have been found. The present paper treats the interaction between...
Shallow Water Waves and Solitary Waves
Hereman, Willy
2013-01-01
Encyclopedic article covering shallow water wave models used in oceanography and atmospheric science. Sections: Definition of the Subject; Introduction and Historical Perspective; Completely Integrable Shallow Water Wave Equations; Shallow Water Wave Equations of Geophysical Fluid Dynamics; Computation of Solitary Wave Solutions; Numerical Methods; Water Wave Experiments and Observations; Future Directions, and Bibliography.
Solitary waves on nonlinear elastic rods. II
DEFF Research Database (Denmark)
Sørensen, Mads Peter; Christiansen, Peter Leth; Lomdahl, P. S.
1987-01-01
In continuation of an earlier study of propagation of solitary waves on nonlinear elastic rods, numerical investigations of blowup, reflection, and fission at continuous and discontinuous variation of the cross section for the rod and reflection at the end of the rod are presented. The results...
Peptide Toxins in Solitary Wasp Venoms
Konno, Katsuhiro; Kazuma, Kohei; Nihei, Ken-ichi
2016-01-01
Solitary wasps paralyze insects or spiders with stinging venom and feed the paralyzed preys to their larva. Accordingly, the venoms should contain a variety of constituents acting on nervous systems. However, only a few solitary wasp venoms have been chemically studied despite thousands of species inhabiting the planet. We have surveyed bioactive substances in solitary wasp venoms found in Japan and discovered a variety of novel bioactive peptides. Pompilidotoxins (PMTXs), in the venoms of the pompilid wasps Anoplius samariensis and Batozonellus maculifrons, are small peptides consisting of 13 amino acids without a disulfide bond. PMTXs slowed Na+ channel inactivation, in particular against neuronal type Na+ channels, and were rather selective to the Nav1.6 channel. Mastoparan-like cytolytic and antimicrobial peptides are the major components of eumenine wasp venoms. They are rich in hydrophobic and basic amino acids, adopting a α-helical secondary structure, and showing mast cell degranulating, antimicrobial and hemolytic activities. The venom of the spider wasp Cyphononyx fulvognathus contained four bradykinin-related peptides. They are hyperalgesic and, dependent on the structure, differently associated with B1 or B2 receptors. Further survey led to the isolation of leucomyosuppressin-like FMRFamide peptides from the venoms of the digger wasps Sphex argentatus and Isodontia harmandi. These results of peptide toxins in solitary wasp venoms from our studies are summarized. PMID:27096870
Peptide Toxins in Solitary Wasp Venoms
Directory of Open Access Journals (Sweden)
Katsuhiro Konno
2016-04-01
Full Text Available Solitary wasps paralyze insects or spiders with stinging venom and feed the paralyzed preys to their larva. Accordingly, the venoms should contain a variety of constituents acting on nervous systems. However, only a few solitary wasp venoms have been chemically studied despite thousands of species inhabiting the planet. We have surveyed bioactive substances in solitary wasp venoms found in Japan and discovered a variety of novel bioactive peptides. Pompilidotoxins (PMTXs, in the venoms of the pompilid wasps Anoplius samariensis and Batozonellus maculifrons, are small peptides consisting of 13 amino acids without a disulfide bond. PMTXs slowed Na+ channel inactivation, in particular against neuronal type Na+ channels, and were rather selective to the Nav1.6 channel. Mastoparan-like cytolytic and antimicrobial peptides are the major components of eumenine wasp venoms. They are rich in hydrophobic and basic amino acids, adopting a α-helical secondary structure, and showing mast cell degranulating, antimicrobial and hemolytic activities. The venom of the spider wasp Cyphononyx fulvognathus contained four bradykinin-related peptides. They are hyperalgesic and, dependent on the structure, differently associated with B1 or B2 receptors. Further survey led to the isolation of leucomyosuppressin-like FMRFamide peptides from the venoms of the digger wasps Sphex argentatus and Isodontia harmandi. These results of peptide toxins in solitary wasp venoms from our studies are summarized.
Giant solitary fibrous tumour of the liver
T. Terkivatan (Türkan); M. Kliffen (Mike); J.H.W. de Wilt (Johannes); A.N. van Geel (Albert); A.M.M. Eggermont (Alexander); C. Verhoef (Kees)
2006-01-01
textabstractBackground: Solitary fibrous tumour (SFT) is an uncommon mesenchymal neoplasm that most frequently affects the pleura, although it has been reported with increasing frequency in various other sites such as in the peritoneum, pericardium and in non-serosal sites such as lung parenchyma,
Solitary Wave Solutions for Zoomeron Equation
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Amna IRSHAD
2013-04-01
Full Text Available Tanh-Coth Method is applied to find solitary wave solutions of the Zoomeron equation which is of extreme importance in mathematical physics. The proposed scheme is fully compatible with the complexity of the problem and is highly efficient. Moreover, suggested combination is capable to handle nonlinear problems of versatile physical nature.
Solitary fibrous tumour of the vagus nerve.
Scholsem, Martin; Scholtes, Felix
2012-04-01
We describe the complete removal of a foramen magnum solitary fibrous tumour in a 36-year-old woman. It originated on a caudal vagus nerve rootlet, classically described as the 'cranial' accessory nerve root. This ninth case of immunohistologically confirmed cranial or spinal nerve SFT is the first of the vagus nerve.
Solitary Wave Propagation Influenced by Submerged Breakwater
Institute of Scientific and Technical Information of China (English)
王锦; 左其华; 王登婷
2013-01-01
The form of Boussinesq equation derived by Nwogu (1993) using velocity at an arbitrary distance and surface elevation as variables is used to simulate wave surface elevation changes. In the numerical experiment, water depth was divided into five layers with six layer interfaces to simulate velocity at each layer interface. Besides, a physical experiment was carried out to validate numerical model and study solitary wave propagation.“Water column collapsing”method (WCCM) was used to generate solitary wave. A series of wave gauges around an impervious breakwater were set-up in the flume to measure the solitary wave shoaling, run-up, and breaking processes. The results show that the measured data and simulated data are in good agreement. Moreover, simulated and measured surface elevations were analyzed by the wavelet transform method. It shows that different wave frequencies stratified in the wavelet amplitude spectrum. Finally, horizontal and vertical velocities of each layer interface were analyzed in the process of solitary wave propagation through submerged breakwater.
Solitary wave interactions of the GRLW equation
Energy Technology Data Exchange (ETDEWEB)
Ramos, J.I. [Room I-320-D, E.T.S. Ingenieros Industriales, Universidad de Malaga, Plaza El Ejido, s/n 29013 Malaga (Spain)]. E-mail: jirs@lcc.uma.es
2007-07-15
An approximate quasilinearization method for the solution of the generalized regularized long-wave (GRLW) equation based on the separation of the temporal and spatial derivatives, three-point, fourth-order accurate, compact difference equations, is presented. The method results in a system of linear equations with tridiagonal matrices, and is applied to determine the effects of the parameters of the GRLW equation and initial conditions on the formation of undular bores and interactions/collisions between two solitary waves. It is shown that the method preserves very accurately the first two invariants of the GRLW equation, the formation of secondary waves is a strong function of the amplitude and width of the initial Gaussian conditions, and the collision between two solitary waves is a strong function of the parameters that appear in the GRLW equation and the amplitude and speed of the initial conditions. It is also shown that the steepening of the leading and trailing waves may result in the formation of multiple secondary waves and/or an undular bore; the former interacts with the trailing solitary wave which may move parallel to or converge onto the leading solitary wave.
Dust mite allergy Overview By Mayo Clinic Staff Dust mite allergy is an allergic reaction to tiny bugs that commonly live in house dust. Signs of dust mite allergy include those common to hay fever, such as ...
Sabetkar, Akbar; Dorranian, Davoud
2016-08-01
Our prime objective of this paper is to examine the parametric regimes for the existence and polarity of dust acoustic double layers (DADLs) and its solitary structures arising from a magnetized self-gravitating opposite polarity dust-plasma (OPDP) model. The constituents of the OPDP model are two species of positively and negatively charged dust grains, Maxwellian electrons and kappa distributed ions. Contributions of gravitational force only on dust grains are taken into account. For weakly nonlinear analysis, the multiple time scale technique has been used to construct the extended Korteweg-de Vries (E-KdV) and modified Korteweg-de Vries (M-KdV) equations. They pinpoint the evolution of DADLs and solitary structures associated with dust acoustic (DA) mode, respectively. The relevant configurational parameters in our study include the superthermality of ions (κ), obliqueness of propagation (θ), ion concentration (δi), static magnetic field B0 (via ω c p , ω c n ), and self-gravitational field (via γ), as well as the density (μ0), charge (α), and mass (β) ratio of positive to negative dust species. The proposed OPDP model permits positive and negative double layer polarities, while higher order nonlinear equation dictates us only positive polarity solitary structures. The main modification due to an increase in self-gravitational field (via γ) is an enhancement in the spatial width of double layers, yet leaving their amplitude, phase speed, and polarity practically unaffected. With enhanced superthermality and other intrinsic parameters in OPDP model, there is an opposite trend in both amplitude and width of double layers, while the amplitude and the width of solitary waves (via M-KdV equation) undergo the identical behaviors. In particular, the amplitude of solitary waves manifests monotonic behavior for permissible range of obliqueness θ, whereas this scenario is acceptable to only width of double layers. The results are discussed in the context of
Pediatric retrograde intra-renal surgery for renal stones <2 cm in solitary kidney
Directory of Open Access Journals (Sweden)
Wael Mohamed Gamal
2016-01-01
Full Text Available Introduction: Management of renal stones in children with a solitary kidney is a challenge. In the current study, the efficacy and safety of retrograde intrarenal surgery (RIRS in these children were determined. Patients and Methods: Records of children with renal stones who were treated at our institute between August 2011 and August 2014 were retrospectively assessed. Inclusion criteria were: Children with single renal stone <2 cm size, in a solitary kidney. A 7.5 Fr flexible ureteroscope (FURS was introduced into the ureter over a hydrophilic guidewire under visual and fluoroscopic guidance - applying a back-loading technique. The stone was completely dusted using 200 μm laser fiber (0.2-0.8 joules power and10-30 Hz frequency. At the end of the maneuver, a 5 Fr JJ stent was inserted into the ureter. The children were discharged home 24 h postoperative - provided that no complications were detected. Results: Fourteen children (3 girls and 11 boys with median age 9.5 years (range 6-12 were included. The mean stone burden was 12.2 ± 1.5 mm (range 9-20. Stones were successfully accessed in all of the cases by the FURS except for 2 cases in whom a JJ stent was inserted into the ureter and left in place for 2 weeks to achieve passive dilatation. All of the stones were dusted completely. The immediate postoperative stone-free rate (SFR was 79%, and the final SFR was 100% after 3 weeks. No intraoperative complications were observed. Conclusions: RIRS for renal stone <2 cm in children with a solitary kidney is a single-session procedure with a high SFR, low complication rate, and is a minimally invasive, natural orifice technique.
Nonlinear dust acoustic waves with polarization force effects in Kappa distribution plasma
Chen, Hui; Zhou, Suyun; Luo, Rongxiang; Liu, Sanqiu
2017-01-01
The propagation characteristics of dust acoustic solitary waves (DASWs) in dusty plasmas with the effects of polarization force and superthermal ions are studied. First, the polarization force induced by superthermal ions is obtained. It is shown that the superthermality of background ions affect the Debye screening of dust grains as well as the polarization force significantly. Then for small amplitude solitary waves, the KdV equation is obtained by applying the reductive perturbation technique. And for the arbitrary amplitude solitary waves, the Sagdeev potential method is employed and the Sagdeev potential is analyzed. In both case, the effects of the polarization force associated the ions’ superthermality on the characteristic of the DASWs are analyzed.
On the solitary wave paradigm for tsunamis
DEFF Research Database (Denmark)
Madsen, Per A.; Fuhrman, David R.; Schäffer, Hemming Andreas
2008-01-01
Since the 1970s, solitary waves have commonly been used to model tsunamis especially in experimental and mathematical studies. Unfortunately, the link to geophysical scales is not well established, and in this work we question the geophysical relevance of this paradigm. In part 1, we simulate...... of finite amplitude solitary wave theory in laboratory studies of tsunamis. We conclude that order-of-magnitude errors in effective temporal and spatial duration occur when this theory is used as an approximation for long waves on a sloping bottom. In part 3, we investigate the phenomenon of disintegration...... of long waves into shorter waves, which has been observed e.g. in connection with the Indian Ocean tsunami in 2004. This happens if the front of the tsunami becomes sufficently steep, and as a result the front turns into an undular bore. We discuss the importance of these very short waves in connection...
A Solitary Plasmocytoma Case Causing Horner Syndrome
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Mustafa Vayvada
2014-08-01
Full Text Available Solitary plasmacytoma is a rare plasma cell tumour, when seen in the chest wall, it is important to diagnose since the treatment scheme and prognosis will vary, compared to primary malignant tumours of the chest wall. A 60-year-old male presented to our clinic with left shoulder pain radiating to the left axilla. Horner%u2019s syndrome symptoms were present, in further examination a chest wall mass located in the left upper lung lobe region was detected. Histopathologic diagnosis was solitary plasmocytoma via video-assisted thoracoscopy. The primary tumor of the rib malignancy causing Horner%u2019s syndrome is discussed with reference to the relevant literature.
Hypokalemia associated with a solitary pulmonary nodule
Saeian, Samira; Ghayumi, Seiyed Mohammad Ali; Shams, Mesbah
2016-01-01
Abstract Background: Differential diagnosis of hypokalemia and adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome often presents challenging in endocrinology and requires careful clinical, biochemical, radiological, and pathological investigations. Hypokalemia is a common abnormality and systematic approach is required to avoid delays in diagnosis of important underlying causes. Case Summary: A 49-year-old woman presented with moderate hypokalemia. Further evaluation showed hypercortisolism due to ectopic ACTH secretion. Chest computed tomography (CT) revealed a peripheral solitary pulmonary nodule. Excision biopsy of the nodule showed carcinoid tumor. After excision biopsy, all of the patient's symptoms improved and electrolytes and ACTH levels also became normal. Conclusion: Carciniod tumors should be considered as a differential diagnosis in patients presenting with hypokalemia and ectopic ACTH syndrome. Carcinoid tumor often present as solitary pulmonary nodule and excision biopsy can be curative. PMID:27977570
Asymptotic Linear Stability of Solitary Water Waves
Pego, Robert L.; Sun, Shu-Ming
2016-12-01
We prove an asymptotic stability result for the water wave equations linearized around small solitary waves. The equations we consider govern irrotational flow of a fluid with constant density bounded below by a rigid horizontal bottom and above by a free surface under the influence of gravity neglecting surface tension. For sufficiently small amplitude waves, with waveform well-approximated by the well-known sech-squared shape of the KdV soliton, solutions of the linearized equations decay at an exponential rate in an energy norm with exponential weight translated with the wave profile. This holds for all solutions with no component in (that is, symplectically orthogonal to) the two-dimensional neutral-mode space arising from infinitesimal translational and wave-speed variation of solitary waves. We also obtain spectral stability in an unweighted energy norm.
From solitary wave to traveling surge
Institute of Scientific and Technical Information of China (English)
宋礼庭
1995-01-01
The solution of kinetic Alfven wave under action of anomalous resistance has two branches: the slow wave, VP
Partial Differential Equations and Solitary Waves Theory
Wazwaz, Abdul-Majid
2009-01-01
"Partial Differential Equations and Solitary Waves Theory" is a self-contained book divided into two parts: Part I is a coherent survey bringing together newly developed methods for solving PDEs. While some traditional techniques are presented, this part does not require thorough understanding of abstract theories or compact concepts. Well-selected worked examples and exercises shall guide the reader through the text. Part II provides an extensive exposition of the solitary waves theory. This part handles nonlinear evolution equations by methods such as Hirota’s bilinear method or the tanh-coth method. A self-contained treatment is presented to discuss complete integrability of a wide class of nonlinear equations. This part presents in an accessible manner a systematic presentation of solitons, multi-soliton solutions, kinks, peakons, cuspons, and compactons. While the whole book can be used as a text for advanced undergraduate and graduate students in applied mathematics, physics and engineering, Part II w...
[Solitary fibrous tumours of the kidney].
Gres, Pascal; Avances, Christophe; Ben Naoum, Kamel; Chapuis, Héliette; Costa, Pierre
2004-02-01
Solitary fibrous tumours (SFT) are mesenchymal tumours that usually arise from the pleura. Renal SFT are exceptional (9 cases reported in the literature). The authors report a new case discovered during assessment of HT and treated by radical right nephrectomy. The histological appearance is characteristic: a tumour with a fibrous centre, composed of a monomorphic proliferation of spindle cells, with positive CD 34, CD 99, and bcl 2 labelling. The prognosis after complete resection is generally favourable.
Solitary vascular malformation of the clitoris.
Haritharan, T; Islah, M; Zulfiqar, A; Thambi Dorai, C R
2006-06-01
Isolated involvement of the clitoris by vascular malformation (VM) is very rare. Clinically, the lesion simulates female pseudohermaphroditism. A five-year-old girl presented with clitoromegaly and a clinical diagnosis of solitary VM of the clitoris was made. Magnetic resonance imaging showed characteristic features and confirmed the diagnosis and the extent of the VM. This is the first reported case of isolated involvement of the clitoris by VM to be diagnosed preoperatively.
Two-color walking Peregrine solitary waves.
Baronio, Fabio; Chen, Shihua; Mihalache, Dumitru
2017-09-15
We study the extreme localization of light, evolving upon a non-zero background, in two-color parametric wave interaction in nonlinear quadratic media. We report the existence of quadratic Peregrine solitary waves, in the presence of significant group-velocity mismatch between the waves (or Poynting vector beam walk-off), in the regime of cascading second-harmonic generation. This finding opens a novel path for the experimental demonstration of extreme rogue waves in ultrafast quadratic nonlinear optics.
Stable complex solitary waves of Sasa Satsuma equation
Indian Academy of Sciences (India)
Sasanka Ghosh
2001-11-01
Existence of a new class of complex solitary waves is shown for Sasa Satsuma equation. These solitary waves are found to be stable in a certain domain of the parameter and become chaotic if the parameter exceeds the value 2.4. Signiﬁcantly, the complex solitary waves propagate at higher bit rate over the most stable solitons under the same conditions of the input parameters.
Numerical Study on Breaking Criteria for Solitary Waves
Institute of Scientific and Technical Information of China (English)
Chung-ren CHOU; Ruey-syan SHIH; John Z. YIM
2003-01-01
Studies of the breaking criteria for solitary waves on a slope are presented in this paper. The boundary element method is used to model the processes of shoaling and breaking of solitary waves on various slopes. Empirical formulae that can be used to characterize the breaking of solitary waves are presented. These include the breaking index, the wave height, the water depth, and the maximum particle velocity at the point of breaking. Comparisons with the results of other researches are given.
Energy Technology Data Exchange (ETDEWEB)
Akhmadaliev, C.
2004-12-01
The aim of this work is to investigate the acoustic wave generation by pulsed and periodically modulated ion beams in different solid materials depending on the beam parameters and to demonstrate the possibility to apply an intensity modulated focused ion beam (FIB) for acoustic emission and for nondestructive investigation of the internal structure of materials on a microscopic scale. The combination of a FIB and an ultrasound microscope in one device can provide the opportunity of nondestructive investigation, production and modification of micro- and nanostructures simultaneously. This work consists of the two main experimental parts. In the first part the process of elastic wave generation during the irradiation of metallic samples by a pulsed beam of energetic ions was investigated in an energy range from 1.5 to 10 MeV and pulse durations of 0.5-5 {mu}s, applying ions with different masses, e.g. oxygen, silicon and gold, in charge states from 1{sup +} to 4{sup +}. The acoustic amplitude dependence on the ion beam parameters like the ion mass and energy, the ion charge state, the beam spot size and the pulse duration were of interest. This work deals with ultrasound transmitted in a solid, i.e. bulk waves, because of their importance for acoustic transmission microscopy and nondestructive inspection of internal structure of a sample. The second part of this work was carried out using the IMSA-100 FIB system operating in an energy range from 30 to 70 keV. The scanning ion acoustic microscope based on this FIB system was developed and tested. (orig.)
Dispersion relation for ion-acoustic waves in plasma%等离子体中离子声波的色散关系
Institute of Scientific and Technical Information of China (English)
张开彪; 王红艳
2013-01-01
以含有满足玻耳兹曼分布的低温电子、远离平衡态的高温电子和离子组成的等离子体为研究对象,推导得到在该等离子体中传播的离子声波的色散关系.利用数值模拟方法讨论系统参数如快电子数、两种电子温度之比和数密度比值对离子声波的色散关系的影响.结果表明:系统参数的变化均会影响和改变着系统的色散关系,其中ω2随快电子数α的增大而增大.%A plasma which consisted of lower temperature Boltzmann distributed electrons,higher temperature non-thermal distributed electrons and ions was studied and the dispersion relation of ionacoustic waves was obtained in this paper.The effects and influences of system parameters,such as the fast electrons number,the ratio of the two electrons temperatures,and the ratio of the two electrons densities on the dispersion relation of the ion-acoustic waves were analyzed carefully by using numerical simulation method.The results showed that variation of the plasma parameters has an important influence on the dispersion relation of this system.In addition,ω2 increase with the increase of the fast electrons number α.
The cruel and unusual phenomenology of solitary confinement
Directory of Open Access Journals (Sweden)
Shaun eGallagher
2014-06-01
Full Text Available What happens when subjects are deprived of intersubjective contact? This paper looks closely at the phenomenology and psychology of one example of that deprivation: solitary confinement. It also puts the phenomenology and psychology of solitary confinement to use in the legal context. Not only is there no consensus on whether solitary confinement is a cruel and unusual punishment, there is no consensus on the definition of the term ‘cruel’ in the use of that legal phrase. I argue that we can find a moral consensus on the meaning of ‘cruelty’ by looking specifically at the phenomenology and psychology of solitary confinement.
The cruel and unusual phenomenology of solitary confinement.
Gallagher, Shaun
2014-01-01
What happens when subjects are deprived of intersubjective contact? This paper looks closely at the phenomenology and psychology of one example of that deprivation: solitary confinement. It also puts the phenomenology and psychology of solitary confinement to use in the legal context. Not only is there no consensus on whether solitary confinement is a "cruel and unusual punishment," there is no consensus on the definition of the term "cruel" in the use of that legal phrase. I argue that we can find a moral consensus on the meaning of "cruelty" by looking specifically at the phenomenology and psychology of solitary confinement.
MALIGNANT CHANGE IN A SOLITARY CYLINDROMA: A RARE CASE REPORT
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Shivaji D
2014-06-01
Full Text Available Cylindroma is a rare tumour which originates from skin appendages. Cylindromas are of two types namely solitary and multiple. Malignant transformation of cylindroma is unusual and is extremely rare in solitary type. They show strong predilection for middle aged and elderly females. We report a case of a 70 year old male patient presented with nodular swelling along with surface ulceration in the right axillary region since six months, which on histopathological examination revealed a case of malignant transformation of benign solitary cylindroma. We report a rare case of malignant cylindroma arising in a patient with solitary cylindroma at an unusual site
Bulk solitary waves in elastic solids
Samsonov, A. M.; Dreiden, G. V.; Semenova, I. V.; Shvartz, A. G.
2015-10-01
A short and object oriented conspectus of bulk solitary wave theory, numerical simulations and real experiments in condensed matter is given. Upon a brief description of the soliton history and development we focus on bulk solitary waves of strain, also known as waves of density and, sometimes, as elastic and/or acoustic solitons. We consider the problem of nonlinear bulk wave generation and detection in basic structural elements, rods, plates and shells, that are exhaustively studied and widely used in physics and engineering. However, it is mostly valid for linear elasticity, whereas dynamic nonlinear theory of these elements is still far from being completed. In order to show how the nonlinear waves can be used in various applications, we studied the solitary elastic wave propagation along lengthy wave guides, and remarkably small attenuation of elastic solitons was proven in physical experiments. Both theory and generation for strain soliton in a shell, however, remained unsolved problems until recently, and we consider in more details the nonlinear bulk wave propagation in a shell. We studied an axially symmetric deformation of an infinite nonlinearly elastic cylindrical shell without torsion. The problem for bulk longitudinal waves is shown to be reducible to the one equation, if a relation between transversal displacement and the longitudinal strain is found. It is found that both the 1+1D and even the 1+2D problems for long travelling waves in nonlinear solids can be reduced to the Weierstrass equation for elliptic functions, which provide the solitary wave solutions as appropriate limits. We show that the accuracy in the boundary conditions on free lateral surfaces is of crucial importance for solution, derive the only equation for longitudinal nonlinear strain wave and show, that the equation has, amongst others, a bidirectional solitary wave solution, which lead us to successful physical experiments. We observed first the compression solitary wave in the
Localization and solitary waves in solid mechanics
Champneys, A R; Thompson, J M T
1999-01-01
This book is a collection of recent reprints and new material on fundamentally nonlinear problems in structural systems which demonstrate localized responses to continuous inputs. It has two intended audiences. For mathematicians and physicists it should provide useful new insights into a classical yet rapidly developing area of application of the rich subject of dynamical systems theory. For workers in structural and solid mechanics it introduces a new methodology for dealing with structural localization and the related topic of the generation of solitary waves. Applications range from classi
Microtubules: A network for solitary waves
Directory of Open Access Journals (Sweden)
Zdravković Slobodan
2017-01-01
Full Text Available In the present paper we deal with nonlinear dynamics of microtubules. The structure and role of microtubules in cells are explained as well as one of models explaining their dynamics. Solutions of the crucial nonlinear differential equation depend on used mathematical methods. Two commonly used procedures, continuum and semi-discrete approximations, are explained. These solutions are solitary waves usually called as kink solitons, breathers and bell-type solitons. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III45010
Asymptotic Methods for Solitary Solutions and Compactons
Directory of Open Access Journals (Sweden)
Ji-Huan He
2012-01-01
Full Text Available This paper is an elementary introduction to some new asymptotic methods for the search for the solitary solutions of nonlinear differential equations, nonlinear differential-difference equations, and nonlinear fractional differential equations. Particular attention is paid throughout the paper to giving an intuitive grasp for the variational approach, the Hamiltonian approach, the variational iteration method, the homotopy perturbation method, the parameter-expansion method, the Yang-Laplace transform, the Yang-Fourier transform, and ancient Chinese mathematics. Hamilton principle and variational principles are also emphasized. The reviewed asymptotic methods are easy to be followed for various applications. Some ideas on this paper are first appeared.
Solitary lucent epiphyseal lesions in children
Energy Technology Data Exchange (ETDEWEB)
Gardner, D.J.; Azouz, E.M.
1988-10-01
We evaluated retrospectively the varying radiographic appearances of 15 solitary lucent epiphyseal lesions occurring in children. Imaging modalities used included plain films, conventional tomography, nuclear scintigraphy, and computed tomography. 40% of the lesions (6) were due to osteomyelitis. The remaining lesions included tuberculosis (1), foreign body granuloma (1), chondroblastoma (2), chondromyoxid fibroma (1), enchondroma (1), osteoid osteoma (2), and eosinophilic granuloma (1). Although the radiographic appearances of such lesions may be particularly characteristic, pathologic correlation is frequently necessary. The high incidence of osteomyelitis in our cases emphasizes its importance as a cause for a lucent epiphyseal lesion.
[Solitary naso-sinusal fibrous tumor].
Martínez, V; Jiménez, M L; Cuatrecasas, M; Jürgens, A; de Amesti, C; Orus, C; Fabra, J M
1995-01-01
Here we present two clinical cases of solitary naso-sinusal fibrous tumour. This tumour has a mesenchymal origin and has an evident pleural location, with well defined immunohistochemical and ultrastructural characteristics. The clinical manifestation is an apparent benign tumour with an inclination to local aggressiveness. The most effective treatment seems to be surgical removal, but given the low number of cases mentioned (there are only eight cases reported in international literature), and the tendency to eventual recurrence, called for cobalt therapy after surgery. The evolution of clinical cases is irregular.
Solitonic and chaotic behaviors for the nonlinear dust-acoustic waves in a magnetized dusty plasma
Zhen, Hui-Ling; Tian, Bo; Xie, Xi-Yang; Wu, Xiao-Yu; Wen, Xiao-Yong
2016-05-01
A model for the nonlinear dust-ion-acoustic waves in a two-ion-temperature, magnetized dusty plasma is studied in this paper. Via the symbolic computation, one-, two- and N-soliton solutions are obtained. It is found that when √{μeμi }parallel during the propagation on the x - y, x - t, and y - t planes, where x, y, and z are the scaled spacial coordinates, and t is the retarded time. Upon the introduction of the driving force Γ(t ) , both the developed and weak chaotic motions as well as the effect of Γ(t ) are explored. Via the phase projections and power spectra, we find the difference between the two chaotic motions roots in the relative magnitude of nonlinearity and external force. Increasing the frequency of the external force or the strength of the damped term can weaken the chaotic motions of such a forced model.
Study on Solitary Waves of a General Boussinesq Model
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
In this paper, we employ the bifurcation method of dynamical systems to study the solitary waves and periodic waves of a generalized Boussinesq equations. All possible phase portraits in the parameter plane for the travelling wave systems are obtained. The possible solitary wave solutions, periodic wave solutions and cusp waves for the general Boussinesq type fluid model are also investigated.
Exact solitary wave solutions of nonlinear wave equations
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The hyperbolic function method for nonlinear wave equations ispresented. In support of a computer algebra system, many exact solitary wave solutions of a class of nonlinear wave equations are obtained via the method. The method is based on the fact that the solitary wave solutions are essentially of a localized nature. Writing the solitary wave solutions of a nonlinear wave equation as the polynomials of hyperbolic functions, the nonlinear wave equation can be changed into a nonlinear system of algebraic equations. The system can be solved via Wu Elimination or Grbner base method. The exact solitary wave solutions of the nonlinear wave equation are obtained including many new exact solitary wave solutions.
The lifecycle of axisymmetric internal solitary waves
Directory of Open Access Journals (Sweden)
J. M. McMillan
2010-09-01
Full Text Available The generation and evolution of solitary waves by intrusive gravity currents in an approximate two-layer fluid with equal upper- and lower-layer depths is examined in a cylindrical geometry by way of theory and numerical simulations. The study is limited to vertically symmetric cases in which the density of the intruding fluid is equal to the average density of the ambient. We show that even though the head height of the intrusion decreases, it propagates at a constant speed well beyond 3 lock radii. This is because the strong stratification at the interface supports the formation of a mode-2 solitary wave that surrounds the intrusion head and carries it outwards at a constant speed. The wave and intrusion propagate faster than a linear long wave; therefore, there is strong supporting evidence that the wave is indeed nonlinear. Rectilinear Korteweg-de Vries theory is extended to allow the wave amplitude to decay as r^{-p} with p=½ and the theory is compared to the observed waves to demonstrate that the width of the wave scales with its amplitude. After propagating beyond 7 lock radii the intrusion runs out of fluid. Thereafter, the wave continues to spread radially at a constant speed, however, the amplitude decreases sufficiently so that linear dispersion dominates and the amplitude decays with distance as r^{-1}.
Radiation therapy for the solitary plasmacytoma
Directory of Open Access Journals (Sweden)
Esengül Koçak
2010-06-01
Full Text Available Plasma-cell neoplasms are classically categorized into four groups as: multiple myeloma (MM, plasma-cell leukemias, solitary plasmacytomas (SP of the bone (SPB, and extramedullary plasmacytomas (EMP. These tumors may be described as localized or diffuse in presentation. Localized plasma-cell neoplasms are rare, and include SP of the skeletal system, accounting for 2-5% of all plasma-cell neoplasms, and EMP of soft tissue, accounting for approximately 3% of all such neoplasms. SP is defined as a solitary mass of neoplastic plasma cells either in the bone marrow or in various soft tissue sites. There appears to be a continuum in which SP often progresses to MM. The main treatment modality for SP is radiation therapy (RT. However, there are no conclusive data in the literature on the optimal RT dose for SP. This review describes the interrelationship of plasma-cell neoplasms, and attempts to determine the minimal RT dose required to obtain local control.
Long solitary internal waves in stable stratifications
Directory of Open Access Journals (Sweden)
W. B. Zimmerman
2004-01-01
Full Text Available Observations of internal solitary waves over an antarctic ice shelf (Rees and Rottman, 1994 demonstrate that even large amplitude disturbances have wavelengths that are bounded by simple heuristic arguments following from the Scorer parameter based on linear theory for wave trapping. Classical weak nonlinear theories that have been applied to stable stratifications all begin with perturbations of simple long waves, with corrections for weak nonlinearity and dispersion resulting in nonlinear wave equations (Korteweg-deVries (KdV or Benjamin-Davis-Ono that admit localized propagating solutions. It is shown that these theories are apparently inappropriate when the Scorer parameter, which gives the lowest wavenumber that does not radiate vertically, is positive. In this paper, a new nonlinear evolution equation is derived for an arbitrary wave packet thus including one bounded below by the Scorer parameter. The new theory shows that solitary internal waves excited in high Richardson number waveguides are predicted to have a halfwidth inversely proportional to the Scorer parameter, in agreement with atmospheric observations. A localized analytic solution for the new wave equation is demonstrated, and its soliton-like properties are demonstrated by numerical simulation.
The solitary sellar plasmacytoma: a diagnostic challenge
Directory of Open Access Journals (Sweden)
Anne Soejbjerg
2016-06-01
Full Text Available Solitary sellar plasmacytomas are exceedingly rare and difficult to distinguish from other pituitary tumors. We report a case of a 62-year-old woman presenting with blurred vision of the right eye and tenderness of the right temporal region, which was interpreted as temporal arteritis. MRI revealed a pituitary mass lesion (20mm×14mm×17mm without compression of the optic chiasm and her pituitary function was normal. Pituitary surgery was undertaken due to growth of the lesion, and histopathological examination showed a highly cellular neoplasm composed of mature monoclonal plasma cells. Subsequent examinations revealed no evidence of extrasellar myeloma. The patient received pituitary irradiation and has remained well and free of symptoms apart from iatrogenic central diabetes insipidus. Until now, only eight cases of solitary sellar plasmacytoma have been reported. Most frequent symptoms stem from compression of the cranial nerves in the cavernous sinus (III, IV, V, whereas the anterior pituitary function is mostly intact.
Solitary fibrous tumor surrounding the carotid sheath.
Gómez-Oliveira, Guillermo; Alvarez-Flores, Modesto; Arribas-García, Ignacio; Martínez-Gimeno, Carlos
2010-03-01
Solitary fibrous tumors (SFTs) are rare spindle cell neoplasms that are mostly found arising from the pleura. Although SFTs recently have been reported in other regions, they are rare in the head and neck and have often been misdiagnosed due to their rarity. SFTs are benign in most cases. Clinically, SFTs usually manifest as well-circumscribed, slow-growing, smooth and painless masses. Symptoms are often minimal, although they may include sore throat, difficulty in swallowing, change of voice or trismus. CT-Scan and MRI are the most sensitive imaging procedures used. The treatment of choice is complete surgical excision of the lesion. Because recurrences have been noted up to 30 years after surgery, long-term follow up is mandatory. In this article, we present a case of a Solitary Fibrous Tumor arising in the parapharyngeal space in a 20-year-old man, involving the carotid sheath, treated by surgical excision with no recurrence after 1 year. The clinical presentation, surgical management and pathological findings are described.
Subsonic ion-acoustic solitons
H ABBASI; Pajouh, H. Hakimi; Shah, H. A.
2005-01-01
In this paper, the nonlinear theory of plasma waves is extended to the plasmas that their equilibrium state are specified by the non-Maxwellian (here kappa) distribution. We believe that the extension is very important since most of the space and some of laboratory plasmas are not in the Maxwellian equilibrium. Although the linear theory of this issue has been known for the decades but, to our knowledge, this is the first attempt in opening the gate to the nonlinear world of plasma waves with...
Energy Technology Data Exchange (ETDEWEB)
Rudakov, D; Yu, J; Boedo, J; Hollmann, E; Krasheninnikov, S; Moyer, R; Muller, S; Yu, A; Rosenberg, M; Smirnov, R; West, W; Boivin, R; Bray, B; Brooks, N; Hyatt, A; Wong, C; Fenstermacher, M; Groth, M; Lasnier, C; McLean, A; Stangeby, P; Ratynskaia, S; Roquemore, A; Skinner, C; Solomon, W M
2008-04-23
Dust production and accumulation impose safety and operational concerns for ITER. Diagnostics to monitor dust levels in the plasma as well as in-vessel dust inventory are currently being tested in a few tokamaks. Dust accumulation in ITER is likely to occur in hidden areas, e.g. between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering resolves size of particles between 0.16-1.6 {micro}m in diameter; the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast-framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in 2D with a single camera or 3D using multiple cameras, but determination of particle size is problematic. In order to calibrate diagnostics and benchmark dust dynamics modeling, pre-characterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase of carbon atomic, C2 dimer, and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.
Solitary plasmacytoma of spine with amyloidosis
Directory of Open Access Journals (Sweden)
Cui-yun SUN
2017-01-01
Full Text Available Objective To report the diagnosis and treatment of one case of solitary plasmacytoma of spine with amyloidosis and investigate the clinicopathological features combined with literatures. Methods and Results The patient was a 46-year-old woman. She suffered from weakness of both lower limbs, unsteady gait and numbness of toes for 20 d. MRI examination revealed an irregular mass behind the spinal cord at T5-7 level and T6-7 vertebral body accessory. The enhanced MRI showed obvious heterogeneous enhancement. The border was clear and spinal dura mater was compressed to shift forward. During operation, T5-7 processus spinosus and vertebral laminae were eroded, and the cortex of bone showed "moth-eaten" erosion. The intraspinal and extradural lesion had rich blood supply, loose bone structure and intact spinal dura mater. Histologically, tumor cells were composed of intensive small cells, and focal plasmacytoid cells were seen. Flake pink staining substance was among them. Artificial cracks were common and multinuclear giant tumor cells were scatteredly distributed. Immunohistochemical analysis showed the cytoplasm of tumor cells were diffusely positive for CD138, CD38 and vimentin (Vim,scatteredly positive for leukocyte common antigen (LCA, and negative for immune globulin κ light chain(IgGκ and λ light chain (IgGλ, CD99, S-100 protein (S-100, pan cytokeratin (PCK, epithelial membrane antigen (EMA, HMB45 and CD34. The Ki-67 labeling index was 1.25%. Congo red staining showed the pink staining substance was brownish red. Hybridization in situ examination showed the DNA content of IgGκ was more than that of IgGλ. The final pathological diagnosis was solitary plasmacytoma of spine with amyloidosis. The patient was treated with postoperative chemotherapy, and there was no recurrence or metastasis during 18-month follow-up period. Conclusions Solitary plasmacytoma of spine with amyloidosis is a rare tumor. The imaging features can offer a few
Weak bond detection in composites using highly nonlinear solitary waves
Singhal, Taru; Kim, Eunho; Kim, Tae-Yeon; Yang, Jinkyu
2017-05-01
We experimentally investigate a diagnostic technique for identifying a weak bond in composites using highly nonlinear solitary waves (HNSWs). We set up a one-dimensional chain of granular crystals, consisting of spherical particles with nonlinear interactions, to generate HNSWs. These solitary wave packets are transmitted into an inspection area of composites by making a direct contact with the chain. We demonstrate that a strong type of solitary waves injected to the weak bond area can break the weak bond of laminates, thereby causing delamination. Then, to identify the creation of the delamination, we transmit a weak type of solitary waves by employing the same apparatus, and measure the solitary waves reflected from the specimens. By analyzing these reflected solitary waves, we differentiate the weak bond samples with the pristine bond ones in an efficient and fast manner. The diagnostic results based on the proposed method are compared with the strength and energy release rate at bond interfaces, which are measured via standard testing methods such as three point bending and end notched flexure tests. This study shows the potential of solitary wave-based detection of weak bonds for hot spot monitoring of composite-based structures.
Non Planar Electrostatic Solitary Wave Structures in Negative Ion Degenerate Plasma
Institute of Scientific and Technical Information of China (English)
S.Hussain; N.Akhtar; Saeed-ur-Rehman
2011-01-01
@@ Theoretical and numerical studies are performed for quantum ion acoustic solitons in planar and non-planar geometries in an unmagnetized homogenous plasma consisting of warm positive and negative ions with nonthermal electrons.A deformed Korteweg de Vries(DKdV)equation is derived by using the reductive perturbation method.The numerical solution to the DKdV equation indicates that the quantum parameter, temperatures of positive ions, temperture of negative ions and electron density blatantly influence the propagation speed and the structure of quantum ion acoustic solitons.The geometrical effects on the structure of quantum ion acoustic wave are discussed.It is shown that the amplitude and propagation speed in spherical geometry is larger as compared to cylinderical and planar geometries for different values of the above-mentioned parameters.%Theoretical and numerical studies are performed for quantum ion acoustic solitons in planar and non-planar geometries in an unmagnetized homogenous plasma consisting of warm positive and negative ions with nonthermal electrons. A deformed Korteweg de Vries (DKdV) equation is derived by using the reductive perturbation method.The numerical solution to the DKdV equation indicates that the quantum parameter, temperatures of positive ions, temperture of negative ions and electron density blatantly influence the propagation speed and the structure of quantum ion acoustic solitons. The geometrical effects on the structure of quantum ion acoustic wave are discussed. It is shown that the amplitude and propagation speed in spherical geometry is larger as compared to cylinderical and planar geometries for different values of the above-mentioned parameters.
A solitary fibrous tumor of the kidney
Directory of Open Access Journals (Sweden)
Anuruddha M Abeygunasekera
2015-01-01
Full Text Available A solitary fibrous tumor (SFT is an uncommon spindle cell neoplasm that usually occurs in the pleura, but may occur in extrapleural sites. Its occurrence in the kidney is rare. We report a SFT, clinically thought to be a renal cell carcinoma arising in the kidney of a 68-year-old female. The tumor was well-circumscribed and composed of a mixture of spindle cells and dense collagenous bands. Immunohistochemical studies revealed reactivity for CD34, CD99, and Bcl-2 protein, with no staining for keratin or muscle markers, confirming the diagnosis. The immunohistochemical study was the key to diagnosis. Several younger members of her family had colorectal and lung cancers suggesting the possibility of a familial or genetic susceptibility.
Solitary waves of the splitted RLW equation
Zaki, S. I.
2001-07-01
A combination of the splitting method and the cubic B-spline finite elements is used to solve the non-linear regularized long wave (RLW) equation. This approach involves a Bubnov-Galerkin method with cubic B-spline finite elements so that there is continuity of the dependent variable and its first derivative throughout the solution region. Time integration of the resulting systems is effected using a Crank-Nicholson approximation. In simulations of the migration of a single solitary wave this algorithm is shown to have higher accuracy and better conservation than a recent splitting difference scheme based on cubic spline interpolation functions, for different amplitudes ranging from a very small ( ⩾0.03) to a considerably high amplitudes ( ⩽0.3). The development of an undular bore is modeled.
Numerical Simulation of Solitary Kinetic Alfven Waves
Institute of Scientific and Technical Information of China (English)
DING Jian; LI Yi; WANG Shui
2008-01-01
Using the two-fluid model in the case of α1 (α=β/2Q, β is the ratio of thermal pressure to magnetic pressure, and Q=m,e/m,I), we numerically investigate the interactions between two solitary kinetic Alfven waves (SKAWs) and between an SKAW and a density discontinuity. The results show that the two SKAWs would remain in their original shapes and propagate at their initiating speeds, which indicates that SKAWs behave just like standard solitons. The simulation also shows that SKAWs will reflect and refract when crossing a discontinuity and propagating into a higher density region. The transmission wave is an SKAW with increasing density, and the reverberation is a disturbance with lower amplitude.
Benign solitary solid cold thyroid nodules
DEFF Research Database (Denmark)
Døssing, Helle; Bennedbaek, Finn Noe; Karstrup, Steen;
2002-01-01
PURPOSE: To evaluate the effects of ultrasonography (US)-guided interstitial laser photocoagulation (ILP) on the volume of benign solitary solid cold thyroid nodules and any nodule-related symptoms. MATERIALS AND METHODS: ILP was performed in 16 patients with normal thyroid function and a solid...... to evaluate the size of the untreated thyroid nodule. RESULTS: In the 16 patients treated with ILP, the mean thyroid nodule volume decreased from 10 to 5.4 mL (P .... Pressure symptoms were significantly reduced (P =.0002) after 6 months. The treatment was well-tolerated in all patients. No significant change in thyroid nodule volume was seen in the control group. CONCLUSION: US-guided ILP could become a useful nonsurgical alternative in the treatment of the benign...
Solitary Plasmacytoma of the Chest Wall
Directory of Open Access Journals (Sweden)
Servet Kayhan
2014-03-01
Full Text Available A previously healthy 55-year-old man with right sided lateral chest pain admitted to clinic. It was found a solid and painful mass at the right 4th rib in physical examination. Chest X-ray and thoracic computarized tomography showed an opacity measured 60x33 mm within the right chest wall destructing the 4th rib. Needle aspiration was performed from tumor and cytologic examination showed atypic plasma cell infiltration. The patient was scheduled for a chest wall resection and reconstructive surgery. Examination of a permanent section showed that the chest wall tumor was solitary plasmacytoma. There was no evidence of multiple myeloma recurrence after two years from the operation.
Transparent lattices and their solitary waves.
Sadurní, E
2014-09-01
We provide a family of transparent tight-binding models with nontrivial potentials and site-dependent hopping parameters. Their feasibility is discussed in electromagnetic resonators, dielectric slabs, and quantum-mechanical traps. In the second part of the paper, the arrays are obtained through a generalization of supersymmetric quantum mechanics in discrete variables. The formalism includes a finite-difference Darboux transformation applied to the scattering matrix of a periodic array. A procedure for constructing a hierarchy of discrete Hamiltonians is indicated and a particular biparametric family is given. The corresponding potentials and hopping functions are identified as solitary waves, pointing to a discrete spinorial generalization of the Korteweg-deVries family.
Solitary vortex couples in viscoelastic Couette flow
Groisman, A; Groisman, Alexander; Steinberg, Victor
1996-01-01
We report experimental observation of a localized structure, which is of a new type for dissipative systems. It appears as a solitary vortex couple ("diwhirl") in Couette flow with highly elastic polymer solutions. A unique property of the diwhirls is that they are stationary, in contrast to the usual localized wave structures in both Hamiltonian and dissipative systems which are stabilized by wave dispersion. It is also a new object in fluid dynamics - a couple of vortices that build a single entity somewhat similar to a magnetic dipole. The diwhirls arise as a result of a purely elastic instability through a hysteretic transition at negligible Reynolds numbers. It is suggested that the vortex flow is driven by the same forces that cause the Weissenberg effect. The diwhirls have a striking asymmetry between the inflow and outflow, which is also an essential feature of the suggested elastic instability mechanism.
Solitary Fibrous Tumor of the Cerebello-Pontine Angle
Biggs, Nigel D.; Fagan, Paul A.; Turner, Jennifer J.; Doust, Bruce
1999-01-01
A case is presented of solitary fibrous tumor occurring in the cerebello-pontine angle. There have been only two other reported cases of a solitary fibrous tumors in this region. Imaging studies showed the tumor to be characteristic in shape and position of an acoustic tumor. However, at surgery the tumor was found to have a “rock hard” consistency. Solitary fibrous tumor differs from acoustic schwannoma and meningioma in its histopathological features and in this case, regrowth, after incomplete excision, was extremely rapid. ImagesFigure 2Figure 3Figure 4Figure 5Figure 6 PMID:17171119
Generation of Solitary Rossby Waves by Unstable Topography
Institute of Scientific and Technical Information of China (English)
YANG Hong-Wei; YIN Bao-Shu; DONG Huan-He
2012-01-01
The effect of topography on generation of the solitary Rossby waves is researched. Here, the topography, as a forcing for waves generation, is taken as a function of longitude variable x and time variable t, which is called unstable topography. With the help of a perturbation expansion method, a forced mKdv equation governing the evolution of amplitude of the solitary Rossby waves is derived from quasi-geostrophic vortieity equation and is solved by the pseudo-spectral method. Basing on the waterfall plots, the generational features of the solitary Rossby waves under the influence of unstable topography and stable topography are compared and some conclusions are obtained.
Energy Technology Data Exchange (ETDEWEB)
Holt, P.F.
1987-01-01
This book discusses the following: the respiratory system; respirable dust; the fate of inhaled dust; translocation and some general effects of inhaled dust; silicosis; experimental research on silica-related disease; natural fibrous silicates; asbestos dust levels and dust sources; asbestos-related diseases - asbestosis, lung cancer, mesothelioma and other diseases, cancers at sites other than lung and pleura; experimental research relating to asbestos-related diseases; asbestos hazard - mineral types and hazardous occupations, neighbourhood and domestic hazard; silicates other than asbestos-man-made mineral fibres, mineral silicates and cement; metals; coal mine dust, industrial carbon and arsenic; natural and synthetic organic substances; dusts that provoke allergic alveolitis; tobacco smoke.
Zhang, Heng; Duan, Wen-Shan; Qi, Xin; Yang, Lei
2016-02-12
Head-on collision and overtaking collision between a KdV solitary wave and an envelope solitary wave are first studied in present paper by using Particle-in-cell (PIC) method in a dusty plasma. There are phase shifts of the KdV solitary wave in both head-on collision and the overtaking collision, while no phase shift is found for the envelop solitary wave in any cases. The remarkable difference between head-on collision and the overtaking collision is that the phase shift of KdV solitary wave increases as amplitude of KdV solitary wave increases in head-on collision, while it decreases as amplitude of the KdV solitary wave increases in the overtaking collision. It is found that the maximum amplitude during the collision process is less than sum of two amplitudes of both solitary waves, but is larger than either of the amplitude.
A plethora of generalised solitary gravity-capillary water waves
Clamond, Didier; Duran, Angel
2014-01-01
The present study describes, first, an efficient algorithm for computing gravity-capillary solitary waves solutions of the irrotational Euler equations and, second, provides numerical evidences of the existence of (likely) an infinite number of generalised solitary waves (i.e. solitary waves with undamped oscillatory wings). Using conformal mapping, the unknown fluid domain (which is to be determined) is mapped into a uniform strip of the complex plane. A Babenko-like equation is then derived from a Lagrangian expressed in the transformed domain. The Babenko equation is then solved numerically using a Levenberg-Marquardt algorithm. Various interesting solutions are computed, some of them being known, some seem to be new. The emergence of generalised solitary waves is shown when the Bond number is increased.
Solitary pulmonary granuloma with marked enhancement on dynamic CT scanning
Energy Technology Data Exchange (ETDEWEB)
Stark, P.; Wong, V.; Gold, P.
1988-10-01
A patient is described who presented with a vividly enhancing solitary pulmonary nodule during dynamic CT scanning. This mass proved to represent a granuloma due to coccidioidomycosis. The presumptive mechanism of enhancement as well as the differential diagnosis are discussed.
Solitary plasmacytoma of the rib: A rare case
Directory of Open Access Journals (Sweden)
Rikki Singal
2011-01-01
Full Text Available Localized solitary plasmacytoma of the bone is a rare disease and is characterized by only one or two isolated bone lesions with no evidence of disease dissemination. We report a case of solitary plasmacytoma of the rib in a 43-year-old female. The patient underwent complete en-bloc resection of the chest wall including rib, muscle, and parietal pleura. Patient is asymptomatic without any recurrence after two and half years of follow up.
Solitary mesenteric vascular anomaly presenting as acute abdomen
Directory of Open Access Journals (Sweden)
Thambidorai C
2008-01-01
Full Text Available A 4-year-old girl with a solitary vascular anomaly of the mesentery presented with acute lower abdominal pain. Despite the use of ultrasound, computed tomography scan and image-guided core biopsies, the lesion was initially mistaken for an inflammatory intra-abdominal mass. The correct diagnosis was made at laparotomy. Solitary vascular anomaly of the mesentery is rare and its presentation as an acute abdomen has not been reported before.
Solitary osteochondroma arising from cervical spina bifida occulta.
Ofluoglu, Ali Ender; Abdallah, Anas; Gokcedag, Akin
2013-01-01
Solitary osteochondromas are common benign long bone tumors originating from cartilage. They may produce a wide variety of symptoms and complications depending on their spinal location. These may include compressive myelopathy, nerve root compression, pathologic fracture and malignant degeneration, or in some cases only pain. Solitary cervical spine osteochondromas have been reported mostly in the neural arch or vertebral body. This report describes a patient presenting with neck pain, with a benign osteochondroma arising in the right bifid C5 lamina.
[Adenocarcinoma of lung cancer with solitary metastasis to the stomach].
Koh, Sung Ae; Lee, Kyung Hee
2014-09-25
Although hematogenous metastasis of cancer to the gastrointestinal track is rare, it sometime has been reported in patients with malignant melanoma and breast cancer. However, it is extremely rare for lung cancer to metastasize to the stomach, not to mention solitary gastric metastasis. Herein, the authors report a case of a 69-year-old man who was initially diagnosed with lung cancer with synchronous primary gastric cancer which proved to be lung cancer with solitary gastric metastasis after the operation.
Solitary Wave in One-dimensional Buckyball System at Nanoscale
Xu, Jun; Zheng, Bowen; Liu, Yilun
2016-01-01
We have studied the stress wave propagation in one-dimensional (1-D) nanoscopic buckyball (C60) system by molecular dynamics (MD) simulation and quantitative modeling. Simulation results have shown that solitary waves are generated and propagating in the buckyball system through impacting one buckyball at one end of the buckyball chain. We have found the solitary wave behaviors are closely dependent on the initial temperature and impacting speed of the buckyball chain. There are almost no dispersion and dissipation of the solitary waves (stationary solitary wave) for relatively low temperature and high impacting speed. While for relatively high temperature and low impacting speed the profile of the solitary waves is highly distorted and dissipated after propagating several tens of buckyballs. A phase diagram is proposed to describe the effect of the temperature and impacting speed on the solitary wave behaviors in buckyball system. In order to quantitatively describe the wave behavior in buckyball system, a simple nonlinear-spring model is established, which can describe the MD simulation results at low temperature very well. The results presented in this work may lay a solid step towards the further understanding and manipulation of stress wave propagation and impact energy mitigation at nanoscale. PMID:26891624
On cusped solitary waves in finite water depth
Liao, Shijun
2013-01-01
It is well-known that the Camassa-Holm (CH) equation admits both of the peaked and cusped solitary waves in shallow water. However, it was an open question whether or not the exact wave equations can admit them in finite water depth. Besides, it was traditionally believed that cusped solitary waves, whose 1st-derivative tends to infinity at crest, are essentially different from peaked solitary ones with finite 1st-derivative. Currently, based on the symmetry and the exact water wave equations, Liao [1] proposed a unified wave model (UWM) for progressive gravity waves in finite water depth. The UWM admits not only all traditional smooth progressive waves but also the peaked solitary waves in finite water depth: in other words, the peaked solitary progressive waves are consistent with the traditional smooth ones. In this paper, in the frame of the linearized UWM, we further give, for the first time, the cusped solitary waves in finite water depth, and besides reveal a close relationship between the cusped and p...
Solitary mammals provide an animal model for autism spectrum disorders.
Reser, Jared Edward
2014-02-01
Species of solitary mammals are known to exhibit specialized, neurological adaptations that prepare them to focus working memory on food procurement and survival rather than on social interaction. Solitary and nonmonogamous mammals, which do not form strong social bonds, have been documented to exhibit behaviors and biomarkers that are similar to endophenotypes in autism. Both individuals on the autism spectrum and certain solitary mammals have been reported to be low on measures of affiliative need, bodily expressiveness, bonding and attachment, direct and shared gazing, emotional engagement, conspecific recognition, partner preference, separation distress, and social approach behavior. Solitary mammals also exhibit certain biomarkers that are characteristic of autism, including diminished oxytocin and vasopressin signaling, dysregulation of the endogenous opioid system, increased Hypothalamic-pituitary-adrenal axis (HPA) activity to social encounters, and reduced HPA activity to separation and isolation. The extent of these similarities suggests that solitary mammals may offer a useful model of autism spectrum disorders and an opportunity for investigating genetic and epigenetic etiological factors. If the brain in autism can be shown to exhibit distinct homologous or homoplastic similarities to the brains of solitary animals, it will reveal that they may be central to the phenotype and should be targeted for further investigation. Research of the neurological, cellular, and molecular basis of these specializations in other mammals may provide insight for behavioral analysis, communication intervention, and psychopharmacology for autism.
Solitary fibrous tumor of the pleura.
Marak, Creticus P; Dorokhova, Olena; Guddati, Achuta K
2013-01-01
Solitary fibrous tumor of the pleura (SFTP) is a rare tumor of mesenchymal origin which can grow to a large size and present with symptoms of cough and pleuritic chest pain. No specific etiological factors for SFTPs are known and they may grow undetected for several years. These tumors are usually benign and may mimic a variety of malignancies. SFTPs are often detected as peripheral opacities on chest X-ray. Unfortunately, fine needle aspiration rarely provides adequate information for a definitive diagnosis. Imaging with computed tomography provides details about the size and extent of any invasion into adjacent tissues. Surgical resection is the mainstay of treatment, and immunohistochemistry of the resected tumor often provides confirmation of the diagnosis. Some SFTPs have been observed to be malignant, and surgical intervention is often lifesaving. There is no adequate data to support the usage of radiotherapy and chemotherapy in the treatment of SFTPs. This tumor exemplifies malignancies which require surgical resection to preempt worse outcomes. Awareness of their presentation and clinical course may help the clinician provide a prompt referral to the thoracic surgeon for resection.
Food searching and superparasitism in solitary parasitoids
Sirot, Etienne; Bernstein, Carlos
Optimality theory predicts that, provided that a larva resulting from superparasitism has some chance of winning the competition with the other larvae present in the host, under certain conditions, solitatry parasitoids should resort to superparasitism. Both theoretical and experimental studies have shown that the life expectancy of the parasitoid has a strong influence on the decision to reject or to accept superparasitism. In many species, life expectancy on its turn depends on the feeding behaviour of the parasitoids, which have to forage for non-host food (mainly plant materials), for the maintenance of their energy reseves. As many solitary parasitoids do not find non-host food in their host patches, they have to choose at each instant whether to search for food or to search for hosts. In this paper, we develop a stochastic dynamic programming model to study the behavioural choice between host and food searching, and its consequences for the acceptance and rejection of superparasitism. We study the influence of habitat quality and parasitoid physiological state on the optimal choice. The model predicts that the crucial point determining the optimal strategy is the balance between egg-and time-limitation.
Intracranial solitary fibrous tumor: Imaging findings
Energy Technology Data Exchange (ETDEWEB)
Clarencon, Frederic, E-mail: fredclare5@msn.com [Department of Neuroradiology, Pitie-Salpetriere Hospital, APHP, 75013 Paris (France); Bonneville, Fabrice [Department of Neuroradiology, Hopital Rangueil, Toulouse University Hospital, 31000 Toulouse (France); Rousseau, Audrey [Department of Neuropathology, Pitie-Salpetriere Hospital (France); Galanaud, Damien [Department of Neuroradiology, Pitie-Salpetriere Hospital, APHP, 75013 Paris (France); Kujas, Michele [Department of Neuropathology, Pitie-Salpetriere Hospital (France); Naggara, Olivier [Department of Neuroradiology, St Anne Hospital, 75014 Paris (France); Cornu, Philippe [Department of Neurosurgery, Pitie-Salpetriere Hospital (France); Chiras, Jacques [Department of Neuroradiology, Pitie-Salpetriere Hospital, APHP, 75013 Paris (France)
2011-11-15
Objective: To study the neuroimaging features of intracranial solitary fibrous tumors (ISFTs). Materials and methods: Retrospective study of neuroimaging features of 9 consecutive histopathologically proven ISFT cases. Location, size, shape, density, signal intensity and gadolinium uptake were studied at CT and MRI. Data collected from diffusion-weighted imaging (DWI) (3 patients), perfusion imaging and MR spectroscopy (2 patients), and DSA (4 patients) were also analyzed. Results: The tumors most frequently arose from the intracranial meninges (7/9), while the other lesions were intraventricular. Tumor size ranged from 2.5 to 10 cm (mean = 6.6 cm). They presented multilobular shape in 6/9 patients. Most ISFTs were heterogeneous (7/9) with areas of low T2 signal intensity that strongly enhanced after gadolinium administration (6/8). Erosion of the skull was present in about half of the cases (4/9). Components with decreased apparent diffusion coefficient were seen in 2/3 ISFTs on DWI. Spectroscopy revealed elevated peaks of choline and myo-inositol. MR perfusion showed features of hyperperfusion. Conclusion: ISFT should be considered in cases of extra-axial, supratentorial, heterogeneous, hypervascular tumor. Areas of low T2 signal intensity that strongly enhance after gadolinium injection are suggestive of this diagnosis. Restricted diffusion and elevated peak of myo-inositol may be additional valuable features.
Solitary magnetic perturbations at the ELM onset
Wenninger, RP; Boom, JE; Burckhart, A; Dunne, MG; Dux, R; Eich, T; Fischer, R; Fuchs, C; Garcia-Munoz, M; Igochine, V; Hoelzl, M; Luhmann, NC; Lunt, T; Maraschek, M; Mueller, HW; Park, HK; Schneider, PA; Sommer, F; Suttrop, W; Viezzer, E
2012-01-01
Edge localised modes (ELMs) allow maintaining sufficient purity of tokamak H-mode plasmas and thus enable stationary H-mode. On the other hand in a future device ELMs may cause divertor power flux densities far in excess of tolerable material limits. The size of the energy loss per ELM is determined by saturation effects in the non-linear phase of the ELM, which at present is hardly understood. Solitary magnetic perturbations (SMPs) are identified as dominant features in the radial magnetic fluctuations below 100kHz. They are typically observed close (+-0.1ms) to the onset of pedestal erosion. SMPs are field aligned structures rotating in the electron diamagnetic drift direction with perpendicular velocities of about 10km/s. A comparison of perpendicular velocities suggests that the perturbation evoking SMPs is located at or inside the separatrix. Analysis of very pronounced examples showed that the number of peaks per toroidal turn is 1 or 2, which is clearly lower than corresponding numbers in linear stabil...
Solitary caecum diverticulitis mimicking acute appendicitis.
Hot, Semih; Eğin, Seracettin; Gökçek, Berk; Yeşiltaş, Metin; Alemdar, Ali; Akan, Arzu; Karahan, Servet Rüştü
2015-12-01
Solitary cecum diverticulum is a benign formation, but it can be complicated with inflammation, perforation and bleeding. Cecum diverticulitis (CD) is the most common complication of caecal diverticulum and it has the highest incidence among Asians, but it is a rare condition in the western world. The incidence of colonic diverticular disease can vary according to national origin, cultural structure and nutritional habits. CD is not common in our country, but it is an important situation because of its clinical similarity with the commonly seen acute right side abdominal diseases like acute appendicitis. Preoperative diagnosis is difficult, and hence, the actual frequency is not known. The treatment of CD can vary from medical therapy to right hemi colectomy. In this study, we presented ten CD cases on whom surgical resection was performed in our surgery unit during the last 8 years. Our purpose was to increase the awareness of surgeons about this situation, and so, make them pay attention for not having their first experience in the operating room.
Krugel, Endrik
2002-01-01
The dielectric permeability; How to evaluate grain cross sections; Very small and very big particles; Case studies of Mie calculus; Particle statistics; The radiative transition probability; Structure and composition of dust; Dust radiation; Dust and its environment; Polarization; Grain alignment; PAHs and spectral features of dust; Radiative transport; Diffuse matter in the Milky Way; Stars and their formation; Emission from young stars. Appendices Mathematical formulae; List of symbols.
Maycroft, Neil; Cheang, Shu Lea
2015-01-01
The fan of a motherboard switches on and off intermittently. It blows household dust, removed from the inside of a computer carcass, into the air. The dust then settles onto the motherboard, to be blown off again. This continual movement of dust is contained in the piece. However, it should remind us that the ceaseless creation and motion of unconfined dust accompanies all stages of the e-waste journey.
Maycroft, Neil; Cheang, Shu Lea
2015-01-01
The fan of a motherboard switches on and off intermittently. It blows household dust, removed from the inside of a computer carcass, into the air. The dust then settles onto the motherboard, to be blown off again. This continual movement of dust is contained in the piece. However, it should remind us that the ceaseless creation and motion of unconfined dust accompanies all stages of the e-waste journey.
Hemenway, Mary Kay; Armosky, Brad J.
2004-01-01
Space is seeming less and less like empty space as new discoveries and reexaminations fill in the gaps. And, ingenuity and technology, like the Spitzer Space Telescope, is allowing examination of the far reaches of the Milky Way and beyond. Even dust is getting its due, but not the dust everyone is familiar with. People seldom consider the dust in…
Effect of superthermal electrons on dust-acoustic Gardner solitons in nonplanar geometry
Indian Academy of Sciences (India)
Deb Kumar Ghosh; Yday Narayan Ghosh; Prasanta Chatterjee; C S Wong
2013-04-01
The properties of nonplanar (cylindrical and spherical) dust-acoustic solitary waves (DASWs) in an unmagnetized, collisionless three-component dusty plasma, whose constituents are negatively charged cold dust fluid, superthermal/non-Maxwellian electrons (represented by kappa distribution) and Boltzmann distributed ions, are investigated by deriving the modified Gardner (MG) equation. The well-known reductive perturbation method is employed to derive the MG equation. The basic features of nonplanar DA Gardner solitons (GSs) are discussed. It is seen that the properties of nonplanar DAGSs (positive and negative) significantly differ as the value of spectral index changes.
Solitary infantile myofibromatosis of the cranial vault: case report.
Merciadri, Paolo; Pavanello, Marco; Nozza, Paolo; Consales, Alessandro; Ravegnani, Giuseppe Marcello; Piatelli, Gianluca; Gandolfo, Carlo; Cama, Armando
2011-04-01
Infantile myofibromatosis is a mesenchymal disorder of early childhood characterized by the formation of tumors in the skin, muscle, viscera, bone, and subcutaneous tissue. Although relatively rare overall, it represents the most common fibrous tumor of infancy. The etiology of this disorder is unknown. Infantile myofibromatosis can present as a solitary or multicentric form. With the multicentric form, bone is often involved, but solitary bone lesions account for only 10% of the cases. Imaging findings are not pathognomonic, and the differential diagnosis usually includes eosinophilic granuloma (Langerhans cell histiocytosis), osteomyelitis, metastasis, osteoblastoma, epidermoid cyst, hemangioma, fibrous dysplasia, fibrosarcoma, and meningioma. A histological pattern is typical, but there are no histopathological differences between the solitary and multicentric forms. Solitary lesions generally have a favorable prognosis if totally removed, with a 10% recurrence rate; incompletely resected lesions recur. We report the case of a 9-year-old boy who came to our attention with a solitary infantile myofibroma of the calvarium, appearing as a tight-elastic, lightly tender mass in the left frontal area, eroding both the inner and the outer tables. Histopathologically, the specimens showed a spindle-cell tumor with dense reticulin fiber network and expression of smooth muscle actin. Fifty-eight months MR follow-up after total removal showed no residual or relapse.
Laparoscopic Rectopexy in Solitary Rectal Ulcer
Directory of Open Access Journals (Sweden)
Hassan Salmanroughani
2011-12-01
Full Text Available Patients with Solitary Rectal Ulcer Syndrome (SRUS come to a physician with passage of mucus and bloody liquid within defecation. The treatment for SRUS is depended to the severity of symptoms and the existance of rectal prolapse. This study is a report of the assessing of rectopexy as surgical modalities for 62 medical treatment resistant SRUS patients who were referred to the gastrointestinal department of Shahid Sadoughi Medical University and Mojibian hospital. The present non-randomized clinical trial was carried out in 62 SRUS patients from 1991 till 2005. In these patients SRUS was confirmed by histology. They were symptomatic after conservative therapy and referred for surgical intervention. All of them had been undergone abdominal rectopexy by two laparoscopic surgeons. In our study, rectal bleeding and history of digitalization had the highest and lowest frequency of symptoms and signs in our cases respectively. Abdominal rectopexy was done in 39 cases and complete recovery in our cases was 69.23%. Complete recovery rate in cases with dysplasia (63.8% was significantly higher than cases without that (P=0.04. Complete recovery rate in cases that had finger defecation (85% was significantly higher than cases without that (50% (P=0.03. Laparoscopic rectopexy is one of the main surgical techniques for treatment of SRUS. This technique can present complete recovery for SRUS patients. Some of them include topical medications, behavior modification supplemented by fiber and biofeedback and surgery were more available and studied. But it seems that education of SRUS patient conservative treatment remain cornerstone in the SRUS management.
Solitary pancreas retransplant: Study of 22 cases
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Tércio Genzini
2006-03-01
Full Text Available Objective: To present our experience with pancreas retransplantin patients previously submitted to simultaneous pancreas-kidneytransplant, pancreas after kidney transplant and pancreastransplant alone. Methods: Between January/1996 and December/2005, 330 pancreas transplants were performed: 308 primarytransplants and 22 (6% retransplants of solitary pancreas. Thefollowing variables were analyzed: patient age; time elapsedbetween the first and the second transplant; causes of loss of thefirst graft; technical characteristics of the transplant andretransplant and the criteria for selecting donors for retransplant.These clinical data were submitted to statistical analysis. Results:The mean age of patients was 34.3 years and the mean elapsedtime between the first and second transplant was 19.3 months.The causes of the first graft loss were venous (8; 35% and arterial(5; 23% thrombosis, chronic rejection (4; 18%, ischemia/reperfusion injury (2, reflux pancreatitis (1, primary non-function(1 and sepsis (1. A second transplant was performed in thesame iliac fossa in 16 patients (72%. Venous drainage wasperformed in the iliac vein in 16 patients (72%, in the inferior venacava in 5 patients (22% and in the portal vein in one patient. 6 allbladder drainage was the technique used in 18 (82% cases andenteric drainage, in 4 patients (18%. Immunosuppressive regimenapplied to all cases was quadruple therapy with antilymphocyteinduction, tacrolimus, mycophenolate mofetil and steroids. Therewas one early death due to sepsis. One-year patient and pancreasgraft survival rates for retransplants were, respectively, 95% and85%. There was no additional risk for removing the pancreas graftat retransplant. Conclusion: Pancreas retransplant was technicallyfeasible in all cases and results similar to those described in theliterature were found for primary pancreas transplant.
Clinicopathological analysis of solitary fibrous tumor
Institute of Scientific and Technical Information of China (English)
Xiumei Zhang; Hai Wang; Shujing Wang; Jinfeng Miao; Zhengai Piao; Yingying Dong
2012-01-01
Objective: The aim of this study was to investigate the clinicopathologic characteristics, diagnosis and differential diagnosis, molecular genetics, treatment and prognosis of solitary fibrous tumor (SFT). Methods: The clinicopathological manifestations were analyzed retrospectively in 22 patients with surgically confirmed SFT. Results: There were 12 male patients and 10 female patients, with the age range 33–67 (mean 48.62) years. The SFTs originated from different from parts of the body, including 13 in the chest, 2 in the lungs, 3 in the abdomen, 1 in the lumbosacral area, 2 in the pelvis, and 1 in the left shoulder. There were 19 benign and 3 malignant tumors. Major clinical presentations were local masses and compression symptoms. Microscopy: the tumor was composed of areas of alternating hypercellularity and hypocellularity. The tumor cells were spindle to short-spindle shaped and arranged in fascicular or storiform pattern and hemangiopericytoma-like structure was presented. Immunohistochemically, Vimentin positive rate was 100% (22/22), Bcl-2 positive rate was 95.5% (21/22), CD99 positive rate was 86.4% (19/22), CD34 positive rate was 81.8 (18/22), focally positive for P53, as well as negative CK, S100 and Desmin. Ki67 labelling index was 2%–30%. Conclusion: SFT is a rare tumor which may be found in various parts of human body. SFT mostly is a benign tumor, but a few could be malignant. Its diagnosis mainly rely on its morphologic features and immunohistochemical profiles. The major treatment is to completely resect it by operation and long-term clinical follow-up is necessary.
Gene expression profiling of solitary fibrous tumors.
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François Bertucci
Full Text Available BACKGROUND: Solitary fibrous tumors (SFTs are rare spindle-cell tumors. Their cell-of-origin and molecular basis are poorly known. They raise several clinical problems. Differential diagnosis may be difficult, prognosis is poorly apprehended by histoclinical features, and no effective therapy exists for advanced stages. METHODS: We profiled 16 SFT samples using whole-genome DNA microarrays and analyzed their expression profiles with publicly available profiles of 36 additional SFTs and 212 soft tissue sarcomas (STSs. Immunohistochemistry was applied to validate the expression of some discriminating genes. RESULTS: SFTs displayed whole-genome expression profiles more homogeneous and different from STSs, but closer to genetically-simple than genetically-complex STSs. The SFTs/STSs comparison identified a high percentage (∼30% of genes as differentially expressed, most of them without any DNA copy number alteration. One of the genes most overexpressed in SFTs encoded the ALDH1 stem cell marker. Several upregulated genes and associated ontologies were also related to progenitor/stem cells. SFTs also overexpressed genes encoding therapeutic targets such as kinases (EGFR, ERBB2, FGFR1, JAK2, histone deacetylases, or retinoic acid receptors. Their overexpression was found in all SFTs, regardless the anatomical location. Finally, we identified a 31-gene signature associated with the mitotic count, containing many genes related to cell cycle/mitosis, including AURKA. CONCLUSION: We established a robust repertoire of genes differentially expressed in SFTs. Certain overexpressed genes could provide new diagnostic (ALDH1A1, prognostic (AURKA and/or therapeutic targets.
Solitary median maxillary central incisor (SMMCI syndrome
Directory of Open Access Journals (Sweden)
Hall Roger K
2006-04-01
Full Text Available Abstract Solitary median maxillary central incisor syndrome (SMMCI is a complex disorder consisting of multiple, mainly midline defects of development resulting from unknown factor(s operating in utero about the 35th–38th day(s from conception. It is estimated to occur in 1:50,000 live births. Aetiology is uncertain. Missense mutation in the SHH gene (I111F at 7q36 may be associated with SMMCI. The SMMCI tooth differs from the normal central incisor, in that the crown form is symmetric; it develops and erupts precisely in the midline of the maxillary dental arch in both primary and permanent dentitions. Congenital nasal malformation (choanal atresia, midnasal stenosis or congenital pyriform aperture stenosis is positively associated with SMMCI. The presence of an SMMCI tooth can predict associated anomalies and in particular the serious anomaly holoprosencephaly. Common congenital anomalies associated with SMMCI are: severe to mild intellectual disability, congenital heart disease, cleft lip and/or palate and less frequently, microcephaly, hypopituitarism, hypotelorism, convergent strabismus, oesophageal and duodenal atresia, cervical hemivertebrae, cervical dermoid, hypothyroidism, scoliosis, absent kidney, micropenis and ambiguous genitalia. Short stature is present in half the children. Diagnosis should be made by eight months of age, but can be made at birth and even prenatally at 18–22 weeks from the routine mid-trimester ultrasound scan. Management depends upon the individual anomalies present. Choanal stenosis requires emergency surgical treatment. Short stature may require growth hormone therapy. SMMCI tooth itself is mainly an aesthetic problem, which is ideally managed by combined orthodontic, prosthodontic and oral surgical treatment; alternatively, it can be left untreated.
Observation of dust acoustic multi-solitons in a strongly coupled dusty plasma
Boruah, A.; Sharma, S. K.; Nakamura, Y.; Bailung, H.
2016-09-01
The excitation and propagation of low frequency dust acoustic multi-solitons are investigated in an unmagnetized strongly coupled dusty plasma. A floating 2D dusty medium is produced in an RF discharge Ar plasma with silica micro-particles. Dust acoustic perturbations are excited by applying a negative sinusoidal pulse of frequency 1-2 Hz and amplitude 4-20 V to an exciter grid. An initial large amplitude dust density compression breaks into a number of solitary pulses which are identified as dust acoustic solitons. The observed multi-soliton evolution is compared with numerical simulations of modified Korteweg de Vries (KdV)-Burger equation. The characteristics of the generated solitons are in good agreement with the theory.
Coupled dust drift acoustic shock and soliton in collisional four component magnetized dusty plasmas
Farooq, M.; Ahmad, Mushtaq; Jan, Qasim
2017-09-01
Low frequency electrostatic coupled dust drift dust acoustic waves are studied in an inhomogeneous, collisional four component dust magnetoplasma composed of dust components of opposite polarity, along with Boltzmannian ions and electrons. The nonlinear evolution equation in the form of an ordinary differential equation and its limiting cases are derived and solved using the Tanh-method. The numerical analysis of the obtained solutions is studied for both laboratory and cosmic plasma systems. It is observed that, depending on the values of the plasma parameters like ion and electron temperatures, and charge number, both rarefactive and compressive shock and solitary waves may exist. It is shown that the concepts of a critical ion and electron temperatures/density in the nonlinear equations treatment, and of a changeover from compressive to rarefactive shock and soliton characters, correspond to the formation of rarefactive regimes, at which the electric stresses maximize and density minimizes.
Linnarsson, Dag; Fubini, Bice; Gerde, Per; Karlsson, Lars L; Loftus, David J; Prisk, G Kim; Staufer, Urs; Tranfield, Erin M; van Westrenen, Wim
2012-01-01
The formation, composition and physical properties of lunar dust are incompletely characterised with regard to human health. While the physical and chemical determinants of dust toxicity for materials such as asbestos, quartz, volcanic ashes and urban particulate matter have been the focus of substantial research efforts, lunar dust properties, and therefore lunar dust toxicity may differ substantially. In this contribution, past and ongoing work on dust toxicity is reviewed, and major knowledge gaps that prevent an accurate assessment of lunar dust toxicity are identified. Finally, a range of studies using ground-based, low-gravity, and in situ measurements is recommended to address the identified knowledge gaps. Because none of the curated lunar samples exist in a pristine state that preserves the surface reactive chemical aspects thought to be present on the lunar surface, studies using this material carry with them considerable uncertainty in terms of fidelity. As a consequence, in situ data on lunar dust...
The novel multi-solitary wave solution to the fifth-order KdV equation
Institute of Scientific and Technical Information of China (English)
Zhang Yi; Chen Deng-Yuan
2004-01-01
By using Hirota's method, the novel multi-solitary wave solutions to the fifth-order KdV equation are obtained.Furthermore, various new solitary wave solutions are also derived by a reconstructed bilinear Backlund transformation.
Diffractons: Solitary Waves Created by Diffraction in Periodic Media
Ketcheson, David I.
2015-03-31
A new class of solitary waves arises in the solution of nonlinear wave equations with constant impedance and no dispersive terms. These solitary waves depend on a balance between nonlinearity and a dispersion-like effect due to spatial variation in the sound speed of the medium. A high-order homogenized model confirms this effective dispersive behavior, and its solutions agree well with those obtained by direct simulation of the variable-coefficient system. These waves are observed to be long-time stable, globally attracting solutions that arise in general as solutions to nonlinear wave problems with periodically varying sound speed. They share some properties with known classes of solitary waves but possess important differences as well.
Shoaling Large Amplitude Internal Solitary Waves in a Laboratory Tank
Allshouse, Michael; Larue, Conner; Swinney, Harry
2014-11-01
The shoaling of internal solitary waves onto the continental shelf can change both the wave dynamics and the state of the environment. Previous observations have demonstrated that these waves can trap fluid and transport it over long distances. Through the use of a camshaft-based wavemaker, we produce large amplitude shoaling waves in a stratified fluid in a laboratory tank. Simulations of solitary waves are used to guide the tuning of the wave generator to approximate solitary waves; thus nonlinear waves can be produced within the 4m long tank. PIV and synthetic schlieren measurements are made to study the transport of fluid by the wave as it moves up a sloping boundary. The results are then compared to numerical simulations and analyzed using finite time Lyapunov exponent calculations. This Lagrangian analysis provides an objective measure of barriers surrounding trapped regions in the flow. Supported by ONR MURI Grant N000141110701 (WHOI).
A rare gigantic solitary cysticercosis pseudotumour of the neck
Directory of Open Access Journals (Sweden)
Seif J Uledi
2010-11-01
Full Text Available Cysticercosis is one of the ancient parasitic infections and endemic in many parts of the developing world. Humans acquire cysticercosis when they ingest pork tapeworm eggs either through faecal-oral route by eating faecally contaminated food or by auto infection.The clinical picture largely depends on the location of larval encystment. Neurocysticercosis is the most common form of presentation. Solitary extra neural lesions are quite rare and fairly small in size.We present a very unique case of 56 year old Malawian female with a very rare, long standing gigantic solitary cysticercosis pseudo tumour of the neck. By far, there is no documented report on incorrigible cysticercosis lesion with such a sheer size.Solitary extraneural cysticercosis lesions may mimic other soft tissue masses; therefore it is important for clinicians working in endemic regions to consider cysticercosis as a differential diagnosis when evaluating patients with soft tissue lesions.
Giant solitary trichoepithelioma with desmoplasia on histopathology: An unusual finding
Directory of Open Access Journals (Sweden)
Sundeep Chowdhry
2016-10-01
Full Text Available Trichoepithelioma is a well-recognized hamartoma of hair germ clinically presenting as solitary or multiple papules. Uncommonly, it may present as a large solitary lesion, termed as giant solitary trichoepithelioma (GST. A 50-year old man presented with a large, pedunculated mass over the root of nose obstructing visual field. It was excised and sent for histopathological examination. H&E staining revealed in addition to characteristic features of trichoepithelioma, a desmoplastic hypocellular stroma. After taking into account the clinical and histopathological features, a diagnosis of GST was made. This case is the first case to the best of authors’ knowledge describing desmoplastic stroma in a case of GST. It is also noteworthy because it reports the largest GST described so far over the nose.
On solitary patterns in Lotka-Volterra chains
Zilburg, Alon; Rosenau, Philip
2016-03-01
We present and study a class of Lotka-Volterra chains with symmetric 2N-neighbors interactions. To identify the types of solitary waves which may propagate along the chain, we study their quasi-continuum approximations which, depending on the coupling between neighbors, reduce into a large variety of partial differential equations. Notable among the emerging equations is a bi-cubic equation {u}t={[{{bu}}2+2κ {{uu}}{xx}+{({u}{xx})}2]}x which we study in some detail. It begets remarkably stable topological and non-topological solitary compactons that interact almost elastically. They are used to identify discretons, their solitary discrete antecedents on the lattice, which decay at a doubly exponential rate. Many of the discrete modes are robust while others either decompose or evolve into breathers.
Solitary calvarial metastases : An unusual presentation of thoracic neuroblastoma
Directory of Open Access Journals (Sweden)
Grover S
2003-01-01
Full Text Available A primary thoracic origin occurs only in 20% of neuroblastomas, and their classical presentation is mediastinal or cord compression. Skeletal metastases of neuroblastomas are characteristically multiple, and calvarial deposits usually show simultaneous involvement of orbit. Solitary metastases in neuroblastoma, is an unusual entity and its presentation as a large calvarial mass, especially from a thoracic primary, is rare. Furthermore, calvarial metastases are relatively uncommon in children compared to adults. We discuss the clinical, radiographic, CT features, and differential diagnosis of a large calvarial mass with sunray spiculation in a child, which was due to a solitary metastases from an occult thoracic neuroblastoma. The possibility of neuroblastoma presenting in this unique fashion and the importance of considering a chemosensitive tumor such as neuroblastoma in the differential diagnosis of a solitary calvarial mass in a child is highlighted by our report.
Numerical Simulation of Cylindrical Solitary Waves in Periodic Media
Quezada de Luna, Manuel
2013-07-14
We study the behavior of nonlinear waves in a two-dimensional medium with density and stress relation that vary periodically in space. Efficient approximate Riemann solvers are developed for the corresponding variable-coefficient first-order hyperbolic system. We present direct numerical simulations of this multiscale problem, focused on the propagation of a single localized perturbation in media with strongly varying impedance. For the conditions studied, we find little evidence of shock formation. Instead, solutions consist primarily of solitary waves. These solitary waves are observed to be stable over long times and to interact in a manner approximately like solitons. The system considered has no dispersive terms; these solitary waves arise due to the material heterogeneity, which leads to strong reflections and effective dispersion.
Clinical analysis of bone scanning in solitary lesion
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
A rational analysis procedure for solitary lesions on whole bone scan-ning was offered. This study was undertaken to analyze retrospectively solitary le-sions which obtained final diagnose through the following aspects: (1) diagnosis ofbone metastasis, (2) the incidence of bone metastasis in different tumor, (3) the mostpossible lesion sites indicating bone metastasis, (4) morphological analysis of solitarylesions. The results are: (1) The incidence of solitary lesions in 2465 cases on wholebone scanning is 15.3%. (2) The rate of bone metastasis is 24.8% in 282 patientswith primary malignancy. The rate of bone metastasis is 6.3% in 64 patients withoutprimary malignancy, and the total diagnostic rate of bone metastasis is 21.4% in 346patients. (3) In patients with primary malignancy, the incidence of bone metastasis ofsolitary lesions is as follows respectively: bronchi cancer 36.1%(22/61); breast cancer23.8%(20/84); prostate gland 17.2%(5/29); other urinary system cancer 22.2%(4/18):G.I. system cancer 16.9%(10/59); others 29.0%(9/31). There is no significant differ-ence in different cancer. (4) In patients without primary malignancy, 93.7%(60/64) ofsolitary lesions are benign. (5) From anatomical point of view, we found the diagnos-tic rate of bone metastasis is as follow: 30% in spine; 34.2% in pelvis; 36.4% in skull;10.8% in other bones. There are significant differences in four groups. It is concludedthat: (1) The diagnostic rate of bone metastasis in solitary lesions is 21.4%. (2) Themost possible solitary lesions indicating osseous tumor spread are at spine, pelvic andskull. (3) Special attention to "cold" and streak like lesions should be paid. (4) Aclinical analysis procedure for diagnosis of solitary lesions has been summarized outhere.``
Serotonin enhances solitariness in phase transition of the migratory locust
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Xiaojiao eGuo
2013-10-01
Full Text Available The behavioral plasticity of locusts is a striking trait presented during the reversible phase transition between solitary and gregarious individuals. However, the results of serotonin as a neurotransmitter from the migratory locust Locusta migratoria in phase transition showed an alternative profile compared to the results from the desert locust Schistoserca gregaria. In this study, we investigated the roles of serotonin in the brain during the phase change of the migratory locust. During the isolation of gregarious nymphs, the concentration of serotonin in the brain increased significantly, whereas serotonin receptors (i.e. 5-HT1, 5-HT2 and 5-HT7 we identified here showed invariable expression patterns. Pharmacological intervention showed that serotonin injection in the brain of gregarious nymphs did not induced the behavior change toward solitariness, but injection of this chemical in isolated gregarious nymphs accelerated the behavioral change from gregarious to solitary phase. During the crowding of solitary nymphs, the concentration of serotonin in the brain remained unchanged, whereas 5-HT2 increased after 1 h of crowding and maintained stable expression level thereafter. Activation of serotonin-5-HT2 signaling with a pharmaceutical agonist inhibited the gregariousness of solitary nymphs in crowding treatment. These results indicate that the fluctuations of serotonin content and 5-HT2 expression are results of locust phase change. Overall, this study demonstrates that serotonin enhances the solitariness of the gregarious locusts. Serotonin may regulate the withdrawal-like behavioral pattern displayed during locust phase change and this mechanism is conserved in different locust species.
Solitary Eccrine Syringofibroadenoma and Successful Treatment with Cryotherapy.
Ozkaya, Dilek Biyik; Su, Ozlem; Bahalı, Anıl Gülsel; Topukçu, Bugce; Dizman, Didem; Tosuner, Zeynep; Demirkesen, Cuyan; Onsun, Nahide
2016-05-01
First described in 1963, eccrine syringofibroadenoma (ESFA) is a rare benign tumor that proliferates with differentiation toward ductal eccrine structures. There are many clinical presentations, including plaques, papules, verrucous plaques, keratotic tumors, and solitary tumors. The age of onset varies, with presentation between 16 and 80 years; however, solitary lesions are seen most commonly in the seventh and eighth decades. Here, we present the case of a 72-year-old woman referred to our outpatient clinic with a nodule on her leg. The histopathology result was ESFA. The lesion regressed after six cryotherapy sessions. Physicians should consider the possibility of ESFA and must remember its malignant potential in elderly patients.
A case of congenital solitary Langerhans cell histiocytoma.
LENUS (Irish Health Repository)
Ricciardo, Bernadette
2012-02-01
A newborn baby boy was referred to the Paediatric Dermatology Unit with a solitary asymptomatic nodule overlying his right nasolabial fold. Complete physical examination, full blood count, serum chemistry, liver function tests and baseline imaging were unremarkable. Histopathological examination showed an atypical dermal infiltrate of mononuclear cells that stained positive with CD1a and S100. A diagnosis of congenital solitary Langerhans cell histiocytoma was made. The lesion completely resolved by 4 months of age. The baby is now 15 months old and repeat systemic evaluation has remained normal.
Measurement of velocity field in parametrically excited solitary waves
Gordillo, Leonardo
2014-01-01
Paramerically excited solitary waves emerge as localized structures in high-aspect-ratio free surfaces subject to vertical vibrations. Herein, we provide the first experimental characterization of the hydrodynamics of thess waves using Particle Image Velocimetry. We show that the underlying velocity field of parametrically excited solitary waves is mainly composed by an oscillatory velocity field. Our results confirm the accuracy of Hamiltonian models with added dissipation in describing this field. Remarkably, our measurements also uncover the onset of a streaming velocity field which is shown to be as important as other crucial nonlinear terms in the current theory. The observed streaming pattern is particularly interesting due to the presence of oscillatory meniscii.
Solitary structures with ion and electron thermal anisotropy
Khusroo, Murchana
2015-01-01
Formation of electrostatic solitary structures are analysed for a magnetised plasma with ion and electron thermal anisotropies. The ion thermal anisotropy is modelled with the help of the Chew-Goldberger-Low (CGL) double adiabatic equations of state while the electrons are treated as inertia-less species with an anisotropic bi-Maxwellian velocity distribution function. A negative electron thermal anisotropy $(T_{e\\perp}/T_e{\\parallel}>1)$ is found to help form large amplitude solitary structures which are in agreement with observational data.
Single-peak solitary wave solutions for the variant Boussinesq equations
Indian Academy of Sciences (India)
Hong Li; Lilin Ma; Dahe Feng
2013-06-01
This paper presents all possible smooth, cusped solitary wave solutions for the variant Boussinesq equations under the inhomogeneous boundary condition. The parametric conditions for the existence of smooth, cusped solitary wave solutions are given using the phase portrait analytical technique. Asymptotic analysis and numerical simulations are provided for smooth, cusped solitary wave solutions of the variant Boussinesq equations.
Existence,Orbital Stability and Instability of Solitary Waves for Coupled BBM Equations
Institute of Scientific and Technical Information of China (English)
Li-wei Cui
2009-01-01
This paper is concerned with the orbital stability/instability of solitary waves for coupled BBM equations which have Hamiltonian form.The explicit solitary wave solutions will be worked out first.Then by detailed spectral analysis and decaying estimates of solutions for the initial value problem,we obtain the orbital stability/instability of solitary waves.
Benedetti, Angela; Baldasano, Jose M.; Basart, Sara; Benincasa, Francesco; Boucher, Olivier; Brooks, Malcolm E.; Chen, Jen-Ping; Colarco, Peter R.; Gong, Sunlin; Huneeus, Nicolas; Jones, Luke; Lu, Sarah; Menut, Laurent; Morcrette, Jean-Jacques; Mulcahy, Jane; Nickovic, Slobodan; Garcia-Pando, Carlos P.; Reid, Jeffrey S.; Sekiyama, Thomas T.; Tanaka, Taichu Y.; Terradellas, Enric; Westphal, Douglas L.; Zhang, Xiao-Ye; Zhou, Chun-Hong
2014-01-01
Over the last few years, numerical prediction of dust aerosol concentration has become prominent at several research and operational weather centres due to growing interest from diverse stakeholders, such as solar energy plant managers, health professionals, aviation and military authorities and policymakers. Dust prediction in numerical weather prediction-type models faces a number of challenges owing to the complexity of the system. At the centre of the problem is the vast range of scales required to fully account for all of the physical processes related to dust. Another limiting factor is the paucity of suitable dust observations available for model, evaluation and assimilation. This chapter discusses in detail numerical prediction of dust with examples from systems that are currently providing dust forecasts in near real-time or are part of international efforts to establish daily provision of dust forecasts based on multi-model ensembles. The various models are introduced and described along with an overview on the importance of dust prediction activities and a historical perspective. Assimilation and evaluation aspects in dust prediction are also discussed.
EXACT SOLITARY WAVE SOLUTIONS OF THETWO NONLINEAR EVOLUTION EQUATIONS
Institute of Scientific and Technical Information of China (English)
ZhuYanjuan; ZhangChunhua
2005-01-01
The solitary wave solutions of the combined KdV-mKdV-Burgers equation and the Kolmogorov-Petrovskii-Piskunov equation are obtained by means of the direct algebra method, which can be generalized to deal with high dimensional nonlinear evolution equations.
Reconstructive surgery in eight children with solitary kidneys
DEFF Research Database (Denmark)
Thorup, Jørgen Mogens
1989-01-01
Within a 10-year period reconstructive urinary tract surgery has been carried out in eight children with solitary kidneys. The children were 0-5 years old. Six had unilateral renal agenesis and two had unilateral multicystic kidney. In five children ureteroneocystostomy was performed, in two...
Observations of Solitary Structures in a Magnetized, Plasma Loaded Waveguide
DEFF Research Database (Denmark)
Lynov, Jens-Peter; Michelsen, Poul; Pécseli, Hans;
1979-01-01
Two types of solitary structure were investigated experimentally and numerically in a magnetized, plasma-loaded waveguide. One was identified as an ordinary KdV soliton and its properties were investigated with particular attention to the damping by resonant particles. The other type of pulse...
INTERNAL TIDES, SOLITARY WAVES AND BORES IN SHALLOW SEAS
Institute of Scientific and Technical Information of China (English)
王涛; 高天赋
2001-01-01
Remote sensing and in situ observations of internal tides, solitary waves and bores in shallow water are briefly reviewed in this paper. The emphasis is laid on interpreting SAR images based on oceanographic measurements, and analyzing characteristics of internal waves in the China Seas. Direc-tions for future research are discussed.
INTERNAL TIDES, SOLITARY WAVES AND BORES IN SHALLOW SEAS
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Remote sensing and in situ observations of internal tides, solitary waves and bores in shallow water are briefly reviewed in this paper. The emphasis is laid on interpreting SAR images based on oceanographic measurements, and analyzing characteristics of internal waves in the China Seas. Directions for future research are discussed.
Sound exposure of professional orchestral musicians during solitary practice.
O'Brien, Ian; Driscoll, Tim; Ackermann, Bronwen
2013-10-01
It is broadly acknowledged that professional orchestral musicians risk noise-induced hearing pathologies due to sound exposure in rehearsal and performance. While much has been published regarding orchestral sound levels, little is known of the sound exposure these musicians experience during solitary practice, despite the many hours they spend engaged in this activity. This study aimed to determine sound exposure during solitary practice of 35 professional orchestral musicians, representing players of most orchestral instruments. To allow cross-comparison, participants were assessed playing similar repertoire in a controlled environment, recording simultaneously at each ear to determine sound exposure levels. Sound levels were recorded between 60 and 107 dB L(Aeq), with peak levels between 101 and 130 dB L(C,peak). For average reported practice durations (2.1 h per day, five days a week) 53% would exceed accepted permissible daily noise exposure in solitary practice, in addition to sound exposure during orchestral rehearsals and performances. Significant inter-aural differences were noted in violin, viola, flute/piccolo, horn, trombone, and tuba. Only 40% used hearing protection at any time while practicing. These findings indicate orchestral musicians at risk of noise-induced hearing loss in ensemble face significant additional risks during solitary practice. Data presented will enable more effective and targeted management strategies for this population.
Solitary waves in a nonintegrable Fermi-Pasta-Ulam chain
Truskinovsky, Lev; Vainchtein, Anna
2014-10-01
We present a family of exact solutions describing discrete solitary waves in a nonintegrable Fermi-Pasta-Ulam chain. The family is sufficiently rich to cover the whole spectrum of known behaviors from delocalized quasicontinuum waves moving with near-sonic velocities to highly localized anticontinuum excitations with only one particle moving at a time.
Transarterial Onyx Embolization of an Orbital Solitary Fibrous Tumor
Hashemi, Nafiseh; Ling, Jeanie D.; Soparkar, Charles; Sami, Mirwat; Ellezam, Benjamin; Klucznik, Richard; Lee, Andrew G.; Chévez-Barrios, Patricia
2015-01-01
Solitary fibrous tumor (SFT) is an uncommon mesenchymal neoplasm sometimes found in the orbit. We report a case of an aggressive orbital SFT with enlarged feeding vessels that was successfully resected immediately after transarterial embolization with Onyx (ethylene vinyl alcohol copolymer). To our knowledge, this is the first report showing the histopathology of Onyx embolization material in an orbital SFT. PMID:27171911
Solitary Wave in Linear ODE with Variable Coefficients
Institute of Scientific and Technical Information of China (English)
LIU Shi-Da; FU Zun-Tao; LIU Shi-Kuo; XIN Guo-Jun; LIANG Fu-Ming; FENG Bei-Ye
2003-01-01
In this paper, the linear ordinary differential equations with variable coefficients are obtained from thecontrolling equations satisfied by wavelet transform or atmospheric internal gravity waves, and these linear equationscan be further transformed into Weber equations. From Weber equations, the homoclinic orbit solutions can be derived,so the solitary wave solutions to linear equations with variable coefficients are obtained.
Solitary Wave and Wave Front as Viewed From Curvature
Institute of Scientific and Technical Information of China (English)
LIU Shi-Kuo; FU Zun-Tao; LIU Shi-Da; LIANG Fu-Ming; XIN Guo-Jun
2004-01-01
The solitary wave and wave front are two important behaviors of nonlinear evolution equations. Geometri cally, solitary wave and wave front are all plane curve. In this paper, they can be represented in terms of curvature c(s), which varies with arc length s. For solitary wave when s →±∞, then its curvature c(s) approaches zero, and when s = 0, the curvature c(s) reaches its maximum. For wave front, when s →±∞, then its curvature c(s) approaches zero, and when s = 0, the curvature c(s) is still zero, but c'(s) ≠ 0. That is, s = 0 is a turning point. When c(s) is given, the variance at some point (x, y) in stream line with arc length s satisfies a 2-order linear variable-coefficient ordinary differential equation. From this equation, it can be determined qualitatively whether the given curvature is a solitary wave or wave front.
Solitary plane waves in an isotropic hexagonal lattice
DEFF Research Database (Denmark)
Zolotaryuk, Yaroslav; Savin, A.V.; Christiansen, Peter Leth
1998-01-01
Solitary plane-wave solutions in a two-dimensional hexagonal lattice which can propagate in different directions on the plane are found by using the pseudospectral method. The main point of our studies is that the lattice model is isotropic and we show that the sound velocity is the same for diff...
A Stylistic Appreciation of William Wordsworth's The Solitary Reaper
Institute of Scientific and Technical Information of China (English)
胡园媛
2009-01-01
This paper, based on the literary stylistic approach, is about the analysis of William Wordsworth's lyrics The Solitary Reaper. The features in its metrics, lexis and imagery explicitly reveal the poet's love for human, passion for nature and principle of simplicity.
Exact Periodic Solitary Solutions to the Shallow Water Wave Equation
Institute of Scientific and Technical Information of China (English)
LI Dong-Long; ZHAO Jun-Xiao
2009-01-01
Exact solutions to the shallow wave equation are studied based on the idea of the extended homoclinic test and bilinear method. Some explicit solutions, such as the one soliton solution, the doubly-periodic wave solution and the periodic solitary wave solutions, are obtained. In addition, the properties of the solutions are investigated.
Internal solitary waves in the Red Sea: An unfolding mystery
da Silva, J.C.B.; Magalhães, J.M.; Gerkema, T.; Maas, L.R.M.
2012-01-01
The off-shelf region between 16.0 degrees and 16.5 degrees N in the southern Red Sea is identified as a new hotspot for the occurrence of oceanic internal solitary waves. Satellite observations reveal trains of solitons that, surprisingly, appear to propagate from the center of the Red Sea, where it
Solitary Wave and Wave Front as Viewed From Curvature
Institute of Scientific and Technical Information of China (English)
LIUShi-Kuo; FUZun-Tao; LIUShi-Da; LIANGFu-Ming; XINGuo-Jun
2004-01-01
The solitary wave and wave front are two important behaviors of nonlinear evolution equations. Geometrically, solitary wave and wave front are all plane curve. In this paper, they can be represented in terms of curvature c(s),which varies with arc length s. For solitary wave when s→±∞, then its curvature c(s) approaches zero, and whens = 0, the curvature c(s) reaches its maximum. For wave front, when s→±∞, then its curvature c(s) approaches zero,and when s = 0, the curvature c(s) is still zero, but c'(s)≠0. That is, s = 0 is a turning point. When c(s) is given,the variance at some point (x, y) in stream line with arc length s satisfies a 2-order linear variable-coeffcient ordinary differential equation. From this equation, it can be determined qualitatively whether the given curvature is a solitary wave or wave front.
Solitary fibrous tumor of the thyroid with capsular invasion.
Bohórquez, Concepción Lara; González-Cámpora, Ricardo; Loscertales, Miguel Congregado; Escudero, Antonio García; Mezquita, Jesús Congregado
2003-01-01
This report describes the clinical and pathologic findings of a peculiar case of solitary fibrous tumor of the thyroid gland that showed capsular invasion. After four and a half years of follow-up, neither local recurrence nor metastasis has developed.
Percutaneous nephrolithotomy in patients with a solitary kidney
Directory of Open Access Journals (Sweden)
Tufan Süelözgen
2014-12-01
Full Text Available Material and method: The results of percutaneous nephrolithotomy applied to 716 patients in our clinic between January 2008 and January 2014 were retrospectively evaluated. Age, gender, urinary calculi size (mm2, urinary calculi localization, ESWL history, operation duration (min, fluoroscopy duration (sec, access type, reason of solitary kidney, hemoglobin drawdown (g/dl and operation success of the patients with a solitary kidney were recorded. The patients having no preoperative and postoperative non contrast abdominal tomography were excluded from the study. Results: Fifteen of nineteen patients (79% were men and 4 of them (21% were women. The average age of the patients was 42.52 ± 16.72 (14-72. Ten patients had anatomical solitary kidney and nine patients had physiological solitary kidney. In fact counter kidney was non functional in 9 patients (47% whereas there was agenesis in 2 (11% and outcome of nephrectomy in 8 (42% patients. In our study, presence of residual stone less than 4 mm at 1st month postoperative non contrast abdominal tomography was accepted as a successful result and accordingly our success rate was detected as 84%. Mean urinary calculi size was 405 ± 252.9 mm2; urinary calculi localization was pelvic, lower pole, upper-middle pole, middle-lower pole and staghorn in 11 (58%, 4 (21%, 1 (5%, 1 (5% and 1 (5% patients, respectively; previous ESWL history was 16%; operation duration was 55.47-± 28.1 min and fluoroscopy duration 131.10 ± 87.6 sec; access type was subcostal in 79%, supracostal in 10.5% and multiple in 10.5%; hemoglobin drawdown was 1.75 ± 0.97 mg/dl. Conclusions: PNL can be effectively and safely administered for the treatment of solitary kidney. In the treatment of large urinary calculi in patients with a solitary kidney, PNL has some advantages such as short surgery duration, less complication, acceptable hemoglobin drawdown and high success rates. According to our study, PNL operation in patients with a
Solitary Large Hepatocellular Carcinoma: Staging and Treatment Strategy.
Directory of Open Access Journals (Sweden)
Po-Hong Liu
Full Text Available Controversies exist on staging and management of solitary large (>5 cm hepatocellular carcinoma (HCC. This study aims to evaluate the impact of tumor size on Barcelona Clinic Liver Cancer (BCLC staging and treatment strategy.BCLC stage A and B patients were included and re-classified as single tumor 2-5 cm or up to 3 tumors ≤3 cm (group A; n = 657, single tumor >5 cm (group SL; n = 224, and multiple tumors >3 cm (group B; n = 351. Alternatively, 240 and 229 patients with solitary large HCC regardless of tumor stage received surgical resection (SR and transarterial chemoembolization (TACE, respectively. The propensity score analysis identified 156 pairs of patients from each treatment arm for survival comparison.The survival was significantly higher for group A but was comparable between group SL and group B patients. Of patients with solitary large HCC, the 1-, 3- and 5-year survival rates were 88% versus 74%, 76% versus 44%, and 63% versus 35% between SR and TACE group, respectively (p<0.001. When baseline demographics were adjusted in the propensity model, the respective 1-, 3- and 5-year survival rates were 87% versus 79%, 76% versus 46%, and 61% versus 36% (p<0.001. The Cox proportional hazards model identified TACE with a 2.765-fold increased risk of mortality compared with SR (95% confidence interval: 1.853-4.127, p<0.001.Patients with solitary large HCC should be classified at least as intermediate stage HCC. SR provides significantly better survival than TACE for solitary large HCC regardless of tumor stage. Further amendment to the BCLC classification is mandatory.
Solitary waves of the EW and RLW equations
Energy Technology Data Exchange (ETDEWEB)
Ramos, J.I. [Room I-320-D, E.T.S. Ingenieros Industriales, Universidad de Malaga, Plaza El Ejido, s/n, 29013 Malaga (Spain)]. E-mail: jirs@lcc.uma.es
2007-12-15
Eight finite difference methods are employed to study the solitary waves of the equal-width (EW) and regularized long-wave (RLW) equations. The methods include second-order accurate (in space) implicit and linearly implicit techniques, a three-point, fourth-order accurate, compact operator algorithm, an exponential method based on the local integration of linear, second-order ordinary differential equations, and first- and second-order accurate temporal discretizations. It is shown that the compact operator method with a Crank-Nicolson discretization is more accurate than the other seven techniques as assessed for the three invariants of the EW and RLW equations and the L {sub 2}-norm errors when the exact solution is available. It is also shown that the use of Gaussian initial conditions may result in the formation of either positive or negative secondary solitary waves for the EW equation and the formation of positive solitary waves with or without oscillating tails for the RLW equation depending on the amplitude and width of the Gaussian initial conditions. In either case, it is shown that the creation of the secondary wave may be preceded by a steepening and an narrowing of the initial condition. The creation of a secondary wave is reported to also occur in the dissipative RLW equation, whereas the effects of dissipation in the EW equation are characterized by a decrease in amplitude, an increase of the width and a curving of the trajectory of the solitary wave. The collision and divergence of solitary waves of the EW and RLW equations are also considered in terms of the wave amplitude and the invariants of these equations.
Energy Technology Data Exchange (ETDEWEB)
El-Hanbaly, A. M.; Sallah, M., E-mail: msallahd@mans.edu.eg [Mansoura University, Physics Department, Faculty of Science (Egypt); El-Shewy, E. K. [Taibah University Al-Madinah Al-Munawarah, Department of Physics (Saudi Arabia); Darweesh, H. F. [Mansoura University, Physics Department, Faculty of Science (Egypt)
2015-10-15
Linear and nonlinear dust-acoustic (DA) waves are studied in a collisionless, unmagnetized and dissipative dusty plasma consisting of negatively charged dust grains, Boltzmann-distributed electrons, and nonthermal ions. The normal mode analysis is used to obtain a linear dispersion relation illustrating the dependence of the wave damping rate on the carrier wave number, the dust viscosity coefficient, the ratio of the ion temperature to the electron temperatures, and the nonthermal parameter. The plasma system is analyzed nonlinearly via the reductive perturbation method that gives the KdV-Burgers equation. Some interesting physical solutions are obtained to study the nonlinear waves. These solutions are related to soliton, a combination between a shock and a soliton, and monotonic and oscillatory shock waves. Their behaviors are illustrated and shown graphically. The characteristics of the DA solitary and shock waves are significantly modified by the presence of nonthermal (fast) ions, the ratio of the ion temperature to the electron temperature, and the dust kinematic viscosity. The topology of the phase portrait and the potential diagram of the KdV-Burgers equation is illustrated, whose advantage is the ability to predict different classes of traveling wave solutions according to different phase orbits. The energy of the soliton wave and the electric field are calculated. The results in this paper can be generalized to analyze the nature of plasma waves in both space and laboratory plasma systems.
Energy Technology Data Exchange (ETDEWEB)
Matt Ryan; David Humphreys [Mining Attachments (Qld.) Pty Ltd. (Australia)
2009-01-15
The coal mining industry has, for many years, used dry stone dust or calcium carbonate (CaCO{sub 3}) in the prevention of the propagation of coal dust explosions throughout their underground mines in Australia. In the last decade wet stone dusting has been introduced. This is where stone dust and water are mixed together to form a paste like slurry. This mixture is pumped and sprayed on to the underground roadway surfaces. This method solved the contamination of the intake airways but brought with it a new problem known as 'caking'. Caking is the hardened layer that is formed as the stone dust slurry dries. It was proven that this hardened layer compromises the dispersal characteristics of the stone dust and therefore its ability to suppress a coal dust explosion. This project set out to prove a specially formulated, non toxic slurry additive and process that could overcome the caking effect. The slurry additive process combines dry stone dust with water to form a slurry. The slurry is then treated with the additive and compressed air to create a highly vesicular foam like stone dusted surface. The initial testing on a range of additives and the effectiveness in minimising the caking effect of wet dusting were performed at Applied Chemical's research laboratory in Melbourne, Victoria and independently tested at the SGS laboratory in Paget, Queensland. The results from these tests provided the platform to conduct full scale spraying trials at the Queensland Mines Rescue Station and Caledon Coal's Cook Colliery, Blackwater. The project moved into the final stage of completion with the collection of data. The intent was to compare the slurry additive process to dry stone dusting in full-scale methane explosions at the CSIR Kloppersbos explosion facility in Kloppersbos, South Africa.
Energy Technology Data Exchange (ETDEWEB)
Guo Shimin [School of Mathematics and Statistics, Xi' an Jiaotong University, Xi' an 710049 (China); Research Group MAC 2, Centrum Wiskunde and Informatica, Amsterdam 1098XG (Netherlands); Wang Hongli [School of Business and Administration, Tongji University, Shanghai 200092 (China); Mei Liquan [School of Mathematics and Statistics, Xi' an Jiaotong University, Xi' an 710049 (China); Center for Computational Geosciences, Xi' an Jiaotong University, Xi' an 710049 (China)
2012-06-15
By combining the effects of bounded cylindrical geometry, azimuthal and axial perturbations, the nonlinear dust acoustic waves (DAWs) in an unmagnetized plasma consisting of negatively charged dust grains, nonextensive ions, and nonextensive electrons are studied in this paper. Using the reductive perturbation method, a (3 + 1)-dimensional variable-coefficient cylindrical Korteweg-de Vries (KdV) equation describing the nonlinear propagation of DAWs is derived. Via the homogeneous balance principle, improved F-expansion technique and symbolic computation, the exact traveling and solitary wave solutions of the KdV equation are presented in terms of Jacobi elliptic functions. Moreover, the effects of the plasma parameters on the solitary wave structures are discussed in detail. The obtained results could help in providing a good fit between theoretical analysis and real applications in space physics and future laboratory plasma experiments where long-range interactions are present.
Respirable dust measured downwind during rock dust application.
Harris, M L; Organiscak, J; Klima, S; Perera, I E
2017-05-01
The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted underground evaluations in an attempt to quantify respirable rock dust generation when using untreated rock dust and rock dust treated with an anticaking additive. Using personal dust monitors, these evaluations measured respirable rock dust levels arising from a flinger-type application of rock dust on rib and roof surfaces. Rock dust with a majority of the respirable component removed was also applied in NIOSH's Bruceton Experimental Mine using a bantam duster. The respirable dust measurements obtained downwind from both of these tests are presented and discussed. This testing did not measure miners' exposure to respirable coal mine dust under acceptable mining practices, but indicates the need for effective continuous administrative controls to be exercised when rock dusting to minimize the measured amount of rock dust in the sampling device.
Flandes, Alberto
2004-08-01
The Dust ballerina skirt is a set of well defined streams composed of nanometric sized dust particles that escape from the Jovian system and may be accelerated up to >=200 km/s. The source of this dust is Jupiter's moon Io, the most volcanically active body in the Solar system. The escape of dust grains from Jupiter requires first the escape of these grains from Io. This work is basically devoted to explain this escape given that the driving of dust particles to great heights and later injection into the ionosphere of Io may give the particles an equilibrium potential that allow the magnetic field to accelerate them away from Io. The grain sizes obtained through this study match very well to the values required for the particles to escape from the Jovian system.
Paradis, D.
2011-12-01
Recent studies have shown evidence for variations in the dust emissivity law with temperature and wavelength. A recent dust emission model, called TLS model (for two-level systems), based on the description of the disordered internal structure of the amorphous dust grains has been developped to interpret observations in the far-infrared/submillimeter (FIR/submm) domain. A recent work focusing on the comparison between data of the diffuse interstellar medium seen by FIRAS-WMAP, as well as Archeops compact sources, with the TLS model allowed us to constrain the model parameters characterizing the general Galactic dust properties. Using the newly available Herschel/Hi-GAL data of the inner Galactic plane, we report a 500 μm emissivity excess in the peripheral parts of the Galactic plane, that can reach up to 20% of the emissivity. Results of the TLS modeling indicate significant changes in the dust properties from the central to peripheral parts of the Galactic plane.
Reconstructive surgery in eight children with solitary kidneys
DEFF Research Database (Denmark)
Thorup, Jørgen Mogens
1989-01-01
Within a 10-year period reconstructive urinary tract surgery has been carried out in eight children with solitary kidneys. The children were 0-5 years old. Six had unilateral renal agenesis and two had unilateral multicystic kidney. In five children ureteroneocystostomy was performed, in two...... of them because of reflux. In two children pyeloureteroplasty was performed, and in one both ureteroneocystostomy and pyeloureteroplasty. The multicystic kidneys were removed. The renal function was poor preoperatively in five children; two of these also had urosepsis. These children were all under 15...... months of age. Postoperatively, the renal function was subnormal (although improved) in two children; in six it was normal. The most important prognostic factors in solitary kidneys with urinary tract obstruction are infection and developmental injury....
Electron acoustic solitary waves with kappa-distributed electrons
Energy Technology Data Exchange (ETDEWEB)
Devanandhan, S; Singh, S V; Lakhina, G S, E-mail: satyavir@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai (India)
2011-08-01
Electron acoustic solitary waves are studied in a three-component, unmagnetized plasma composed of hot electrons, fluid cold electrons and ions having finite temperatures. Hot electrons are assumed to have kappa distribution. The Sagdeev pseudo-potential technique is used to study the arbitrary amplitude electron-acoustic solitary waves. It is found that inclusion of cold electron temperature shrinks the existence regime of the solitons, and soliton electric field amplitude decreases with an increase in cold electron temperature. A decrease in spectral index, {kappa}, i.e. an increase in the superthermal component of hot electrons, leads to a decrease in soliton electric field amplitude as well as the soliton velocity range. The soliton solutions do not exist beyond T{sub c}/T{sub h}>0.13 for {kappa}=3.0 and Mach number M=0.9 for the dayside auroral region parameters.
NUMERICAL STUDY OF SOLITARY WAVE FISSION OVER AN UNDERWATER STEP
Institute of Scientific and Technical Information of China (English)
LU Ji; YU Xi-ping
2008-01-01
Solitary wave fission over an underwater step is numerically investigated. The numerical model is based on the enhanced Boussinesq equations, which appropriately represent both the nonlinearity and dispersivity of surface water waves. The finite difference method defined on the staggered grid in space with an implicit scheme for time stepping is employed for the numerical solution of the governing equations. It is demonstrated that Boussinesq type equations, though they are vertically integrated, can describe the details of the solitary wave fission process with very good accuracy. Numerical results of the reflected and transmitting wave heights, the number of solitons emitted from the transmitting wave and their amplitudes all agree very well with the analytical solution derived from KdV equation by virtue of a linear long wave approximation in the vicinity of the underwater step.
[Solitary fibrous tumor of endometrium--a case report].
Dvořák, O; Dvořáková, E; Laco, J; Spaček, J
2013-06-01
Solitary fibrous tumor (SFT) is an uncommon mesenchymal tumor. We present a case of SFT occurring in endometrium. Case report. Department of Obstetrics and Gynecology, The Fingerland Department of Pathology, Medical Faculty of Charles University and Faculty Hospital Hradec Králové. We report a case of 57 years old woman with SFT arising from the endometrium, which was diagnosed and treated at our department. Histological finding was supported by typical immunohistochemical profile of the tumor. Aggressive nature of the tumor wasnt showed. The patient underwent abdominal hysterectomy with bilateral adnexectomy and is followed up in regular periods. Occurence of solitary fibrous tumor (SFT) in the female genital tract is extremely rare. To the best of our knowledge, we report the first case of SFT occurring in endometrium. Because of potencial aggressive behaviour of the tumor complete surgical excision and close follow-up is highly recommended.
Primary Intrapulmonary Thymoma Presenting as a Solitary Pulmonary Nodule
Jung, Woohyun; Kang, Chang Hyun; Kim, Young Tae; Park, In Kyu
2017-01-01
Primary intrapulmonary thymoma (PIT) is a very rare lesion of uncertain pathogenesis. PIT should be considered when the histopathological appearance of a lung tumor shows features that are uncommon but similar to those of a thymoma. In this case report, we discuss the case of a 59-year-old female with a solitary pulmonary nodule that was confirmed to be PIT on the basis of pathological tests. Treatment with complete resection showed good results. PMID:28180106
The frustrated Brownian motion of nonlocal solitary waves
Folli, Viola
2010-01-01
We investigate the evolution of solitary waves in a nonlocal medium in the presence of disorder. By using a perturbational approach, we show that an increasing degree of nonlocality may largely hamper the Brownian motion of self-trapped wave-packets. The result is valid for any kind of nonlocality and in the presence of non-paraxial effects. Analytical predictions are compared with numerical simulations based on stochastic partial differential equation
Exact Solitary Wave Solution in the ZK-BBM Equation
Directory of Open Access Journals (Sweden)
Juan Zhao
2014-01-01
Full Text Available The traveling wave solution for the ZK-BBM equation is considered, which is governed by a nonlinear ODE system. The bifurcation structure of fixed points and bifurcation phase portraits with respect to the wave speed c are analyzed by using the dynamical system theory. Furthermore, the exact solutions of the homoclinic orbits for the nonlinear ODE system are obtained which corresponds to the solitary wave solution curve of the ZK-BBM equation.
Existence of solitary waves in dipolar quantum gases
Antonelli, Paolo
2011-02-01
We study a nonlinear Schrdinger equation arising in the mean field description of dipolar quantum gases. Under the assumption of sufficiently strong dipolar interactions, the existence of standing waves, and hence solitons, is proved together with some of their properties. This gives a rigorous argument for the possible existence of solitary waves in BoseEinstein condensates, which originate solely due to the dipolar interaction between the particles. © 2010 Elsevier B.V. All rights reserved.
Nonlinear dynamics of DNA - Riccati generalized solitary wave solutions
Energy Technology Data Exchange (ETDEWEB)
Alka, W.; Goyal, Amit [Department of Physics, Panjab University, Chandigarh-160014 (India); Nagaraja Kumar, C., E-mail: cnkumar@pu.ac.i [Department of Physics, Panjab University, Chandigarh-160014 (India)
2011-01-17
We study the nonlinear dynamics of DNA, for longitudinal and transverse motions, in the framework of the microscopic model of Peyrard and Bishop. The coupled nonlinear partial differential equations for dynamics of DNA model, which consists of two long elastic homogeneous strands connected with each other by an elastic membrane, have been solved for solitary wave solution which is further generalized using Riccati parameterized factorization method.
Nonlinear dynamics of DNA - Riccati generalized solitary wave solutions
Alka, W.; Goyal, Amit; Nagaraja Kumar, C.
2011-01-01
We study the nonlinear dynamics of DNA, for longitudinal and transverse motions, in the framework of the microscopic model of Peyrard and Bishop. The coupled nonlinear partial differential equations for dynamics of DNA model, which consists of two long elastic homogeneous strands connected with each other by an elastic membrane, have been solved for solitary wave solution which is further generalized using Riccati parameterized factorization method.
Phase modulated solitary waves controlled by bottom boundary condition
Mukherjee, Abhik
2014-01-01
A forced KdV equation is derived to describe weakly nonlinear, shallow water surface wave propagation over non trivial bottom boundary condition. We show that different functional forms of bottom boundary conditions self-consistently produce different forced kdV equations as the evolution equations for the free surface. Solitary wave solutions have been analytically obtained where phase gets modulated controlled by bottom boundary condition whereas amplitude remains constant.
Conjugate flows and amplitude bounds for internal solitary waves
Directory of Open Access Journals (Sweden)
N. I. Makarenko
2009-03-01
Full Text Available Amplitude bounds imposed by the conservation of mass, momentum and energy for strongly nonlinear waves in stratified fluid are considered. We discuss the theoretical scheme which allows to determine broadening limits for solitary waves in the terms of a given upstream density profile. Attention is focused on the continuously stratified flows having multiple broadening limits. The role of the mean density profile and the influence of fine-scale stratification are analyzed.
Solitary rectal ulcer syndrome in children: A literature review
Dehghani, Seyed Mohsen; Malekpour, Abdorrasoul; HAGHIGHAT, MAHMOOD
2012-01-01
Solitary rectal ulcer syndrome (SRUS) is a benign and chronic disorder well known in young adults and less in children. It is often related to prolonged excessive straining or abnormal defecation and clinically presents as rectal bleeding, copious mucus discharge, feeling of incomplete defecation, and rarely rectal prolapse. SRUS is diagnosed based on clinical symptoms and endoscopic and histological findings. The current treatments are suboptimal, and despite correct diagnosis, outcomes can ...
Solitary Fibrous Tumors and So-Called Hemangiopericytoma
Directory of Open Access Journals (Sweden)
Nicolas Penel
2012-01-01
Full Text Available We have reviewed the literature data regarding the spectrum of tumors including solitary fibrous tumor and hemangiopericytoma with special focus on definition of the disease, discussion of the criteria for malignancy, and the key elements of standard treatment of localized disease. We have discussed the emerging concepts on the tumor biology and the different systemic treatments (chemotherapy and molecular-targeted therapies.
Turing patterns and solitary structures under global control
Pismen, L M
1994-01-01
Striped Turing patterns and solitary band and disk structures are constructed using a three-variable multiscale model with cubic nonlinearity and global control. The existence and stability conditions of regular structures are analysed using the equation of motion of curved boundaries between alternative states of the short-range component. The combined picture of transitions between striped and spotted patterns with changing level of global control is in qualitative agreement with the results of the computer experiment by Middya and Luss
Energetics of internal solitary waves in a background sheared current
Directory of Open Access Journals (Sweden)
K. G. Lamb
2010-10-01
Full Text Available The energetics of internal waves in the presence of a background sheared current is explored via numerical simulations for four different situations based on oceanographic conditions: the nonlinear interaction of two internal solitary waves; an internal solitary wave shoaling through a turning point; internal solitary wave reflection from a sloping boundary and a deep-water internal seiche trapped in a deep basin. In the simulations with variable water depth using the Boussinesq approximation the combination of a background sheared current, bathymetry and a rigid lid results in a change in the total energy of the system due to the work done by a pressure change that is established across the domain. A final simulation of the deep-water internal seiche in which the Boussinesq approximation is not invoked and a diffuse air-water interface is added to the system results in the energy remaining constant because the generation of surface waves prevents the establishment of a net pressure increase across the domain. The difference in the perturbation energy in the Boussinesq and non-Boussinesq simulations is accounted for by the surface waves.
Solitary wave shoaling and breaking in a regularized Boussinesq system
Senthilkumar, Amutha
2016-01-01
A coupled BBM system of equations is studied in the situation of water waves propagating over decreasing fluid depth. A conservation equation for mass and a wave breaking criterion valid in the Boussinesq approximation is found. A Fourier collocation method coupled with a 4-stage Runge-Kutta time integration scheme is employed to approximate solutions of the BBM system. The mass conservation equation is used to quantify the role of reflection in the shoaling of solitary waves on a sloping bottom. Shoaling results based on an adiabatic approximation are analyzed. Wave shoaling and the criterion of breaking solitary waves on a sloping bottom is studied. To validate the numerical model the simulation results are compared with those obtained by Grilli et al.[16] and a good agreement between them is observed. Shoaling of solitary waves of two different types of mild slope model systems in [8] and [13] are compared, and it is found that each of these models works well in their respective regimes of applicability.
Mechanisms of metal dusting corrosion
DEFF Research Database (Denmark)
Hummelshøj, Thomas Strabo
In this thesis the early stages of metal dusting corrosion is addressed; the development of carbon expanded austenite, C, and the decomposition hereof into carbides. Later stages of metal dusting corrosion are explored by a systematic study of stainless steel foils exposed to metal dusting...... influence of oxygen and carbon on the metal dusting corrosion is explored. The results indicate that exposure to metal dusting conditions have a detrimental effect on the resistance against oxidation and, conversely, that exposure to oxidation has a detrimental effect on the resistance towards metal dusting....... Consequently, a combination of carburizing and oxidizing conditions has a strong mutual catalyzing effect on the metal dusting corrosion....
Composite circumstellar dust grains
Gupta, Ranjan; Vaidya, Dipak B.; Dutta, Rajeshwari
2016-10-01
We calculate the absorption efficiencies of composite silicate grains with inclusions of graphite and silicon carbide in the spectral range 5-25 μm. We study the variation in absorption profiles with volume fractions of inclusions. In particular we study the variation in the wavelength of peak absorption at 10 and 18 μm. We also study the variation of the absorption of porous silicate grains. We use the absorption efficiencies to calculate the infrared flux at various dust temperatures and compare with the observed infrared emission flux from the circumstellar dust around some M-type and asymptotic giant branch stars obtained from IRAS and a few stars from Spitzer satellite. We interpret the observed data in terms of the circumstellar dust grain sizes, shape, composition and dust temperature.
Composite Circumstellar Dust Grains
Gupta, Ranjan; Dutta, Rajeshwari
2016-01-01
We calculate the absorption efficiencies of composite silicate grains with inclusions of graphite and silicon carbide in the spectral range 5--25$\\rm \\mu m$. We study the variation in absorption profiles with volume fractions of inclusions. In particular we study the variation in the wavelength of peak absorption at 10 and 18$\\rm \\mu m$. We also study the variation of the absorption of porous silicate grains. We use the absorption efficiencies to calculate the infrared flux at various dust temperatures and compare with the observed infrared emission flux from the circumstellar dust around some M-Type \\& AGB stars obtained from IRAS and a few stars from Spitzer satellite. We interpret the observed data in terms of the circumstellar dust grain sizes; shape; composition and dust temperature.
National Aeronautics and Space Administration — We propose to develop a new highly sensitive instrument to confirm the existence of the so-called nano-dust particles, characterize their impact parameters, and...
Numerical Modelling of Solitary Wave Experiments on Rubble Mound Breakwaters
Guler, H. G.; Arikawa, T.; Baykal, C.; Yalciner, A. C.
2016-12-01
Performance of a rubble mound breakwater protecting Haydarpasa Port, Turkey, has been tested under tsunami attack by physical model tests conducted at Port and Airport Research Institute (Guler et al, 2015). It is aimed to understand dynamic force of the tsunami by conducting solitary wave tests (Arikawa, 2015). In this study, the main objective is to perform numerical modelling of solitary wave tests in order to verify accuracy of the CFD model IHFOAM, developed in OpenFOAM environment (Higuera et al, 2013), by comparing results of the numerical computations with the experimental results. IHFOAM is the numerical modelling tool which is based on VARANS equations with a k-ω SST turbulence model including realistic wave generation, and active wave absorption. Experiments are performed using a Froude scale of 1/30, measuring surface elevation and flow velocity at several locations in the wave channel, and wave pressure around the crown wall of the breakwater. Solitary wave tests with wave heights of H=7.5 cm and H=10 cm are selected which represent the results of the experiments. The first test (H=7.5 cm) is the case that resulted in no damage whereas the second case (H=10 cm) resulted in total damage due to the sliding of the crown wall. After comparison of the preliminary results of numerical simulations with experimental data for both cases, it is observed that solitary wave experiments could be accurately modeled using IHFOAM focusing water surface elevations, flow velocities, and wave pressures on the crown wall of the breakwater (Figure, result of sim. at t=29.6 sec). ACKNOWLEDGEMENTSThe authors acknowledge developers of IHFOAM, further extend their acknowledgements for the partial supports from the research projects MarDiM, ASTARTE, RAPSODI, and TUBITAK 213M534. REFERENCESArikawa (2015) "Consideration of Characteristics of Pressure on Seawall by Solitary Waves Based on Hydraulic Experiments", Jour. of Japan. Soc. of Civ. Eng. Ser. B2 (Coast. Eng.), Vol 71, p I
Bifurcation and Solitary-Like Solutions for Compound KdV-Burgers-Type Equation
Directory of Open Access Journals (Sweden)
Yin Li
2015-01-01
Full Text Available Firstly, based on the improved sub-ODE method and the bifurcation method of dynamical systems, we investigate the bifurcation of solitary waves in the compound KdV-Burgers-type equation. Secondly, numbers of solitary patterns solutions are given for each parameter condition and numerical simulations are used to display the dynamical characteristics. Finally, we obtain twelve solitary patterns solutions under some parameter conditions, such as the trigonometric function solutions and the hyperbolic function solutions.
Dust Versus Cosmic Acceleration
Aguirre, A N
1999-01-01
Two groups have recently discovered a statistically significant deviation in the fluxes of high-redshift type Ia supernovae from the predictions of a Friedmann model with zero cosmological constant. This letter argues that bright, dusty, starburst galaxies would preferentially eject a dust component with a shallower opacity curve (hence less reddening) and a higher opacity/mass than the observed galactic dust which is left behind. Such dust could cause the falloff in flux at high-z without violating constraints on reddening or metallicity. The specific model presented is of needle-like dust, which is expected from the theory of crystal growth and has been detected in samples of interstellar dust. Carbon needles with conservative properties can supply the necessary opacity, and would very likely be ejected from galaxies as required. The model is not subject to the arguments given in the literature against grey dust, but may be constrained by future data from supernova searches done at higher redshift, in clust...
Newton to Einstein — dust to dust
Energy Technology Data Exchange (ETDEWEB)
Kopp, Michael; Uhlemann, Cora; Haugg, Thomas, E-mail: michael.kopp@physik.lmu.de, E-mail: cora.uhlemann@physik.lmu.de, E-mail: thomas.haugg@physik.lmu.de [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilian University Munich, Theresienstr. 37, Munich, 80333 (Germany)
2014-03-01
We investigate the relation between the standard Newtonian equations for a pressureless fluid (dust) and the Einstein equations in a double expansion in small scales and small metric perturbations. We find that parts of the Einstein equations can be rewritten as a closed system of two coupled differential equations for the scalar and transverse vector metric perturbations in Poisson gauge. It is then shown that this system is equivalent to the Newtonian system of continuity and Euler equations. Brustein and Riotto (2011) conjectured the equivalence of these systems in the special case where vector perturbations were neglected. We show that this approach does not lead to the Euler equation but to a physically different one with large deviations already in the 1-loop power spectrum. We show that it is also possible to consistently set to zero the vector perturbations which strongly constrains the allowed initial conditions, in particular excluding Gaussian ones such that inclusion of vector perturbations is inevitable in the cosmological context. In addition we derive nonlinear equations for the gravitational slip and tensor perturbations, thereby extending Newtonian gravity of a dust fluid to account for nonlinear light propagation effects and dust-induced gravitational waves.
Transition from Solitons to Solitary Waves in the Fermi-Pasta-Ulam Lattice
Wen, Zhenying; Wei, Nian
2016-01-01
In this paper, we study the smooth transition from solitons to solitary waves in localization, relation between energy and velocity, propagation and scattering property in the Fermi-Pasta-Ulam lattice analytically and numerically. A soliton is a very stable solitary wave that retains its permanent structure after interacting with other solitary waves. A soliton exists when the energy is small, and it becomes a solitary wave when the energy increases to the threshold. The transition could help to understand the distinctly different heat conduction behaviors of the Fermi-Pasta-Ulam lattice at low and high temperature.
Dalgic, Tahsin; Bostanci, Erdal Birol; Cakir, Tebessum; Ozer, Ilter; Ulas, Murat; Aydog, Gulden; Akoglu, Musa
2015-01-01
Colonic solitary plasmacytoma is a rare disease, with few reports occurring in the literature. Solitary plasmacytoma is defined as a plasma cell tumour with no evidence of bone marrow infiltration. Plasmacytoma can present as a solitary tumour in bone or in other parts of the body. The gastrointestinal tract is rarely the site of the disease. We report on the case of a 51-year-old man presenting with a colonic symptomatic mass with unclear biopsy results. A resected specimen showed a solitary plasmacytoma. Surgical resection was an adequate treatment modality in this case. Endoscopic resection, radiotherapy, and chemotherapy are also preferred treatments in selected gastrointestinal plasmacytoma cases. PMID:25954564
Directory of Open Access Journals (Sweden)
Tahsin Dalgic
2015-01-01
Full Text Available Colonic solitary plasmacytoma is a rare disease, with few reports occurring in the literature. Solitary plasmacytoma is defined as a plasma cell tumour with no evidence of bone marrow infiltration. Plasmacytoma can present as a solitary tumour in bone or in other parts of the body. The gastrointestinal tract is rarely the site of the disease. We report on the case of a 51-year-old man presenting with a colonic symptomatic mass with unclear biopsy results. A resected specimen showed a solitary plasmacytoma. Surgical resection was an adequate treatment modality in this case. Endoscopic resection, radiotherapy, and chemotherapy are also preferred treatments in selected gastrointestinal plasmacytoma cases.
Calculation and analysis of solitary waves and kinks in elastic tubes
2013-01-01
The paper is devoted to analysis of different models that describe waves in fluid-filled and gas-filled elastic tubes and development of methods of calculation and numerical analysis of solutions with solitary waves and kinks for these models. Membrane model and plate model are used for tube. Two types of solitary waves are found. One-parametric families are stable and may be used as shock structures. Null-parametric solitary waves are unstable. The process of split of such solitary waves is ...
Interaction of Submerged Breakwater by a Solitary Wave Using WC-SPH Method
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Afshin Mansouri
2014-01-01
Full Text Available Interaction of a solitary wave and submerged breakwater is studied in a meshless, Lagrangian approach. For this purpose, a two-dimensional smoothed particle hydrodynamics (SPH code is developed. Furthermore, an extensive set of simulations is conducted. In the first step, the generated solitary wave is validated. Subsequently, the interaction of solitary wave and submerged breakwater is investigated thoroughly. Results of the interaction of solitary wave and a submerged breakwater are also shown to be in good agreement with published experimental studies. Afterwards, the effects of the inclination and length of breakwater as well as distance between two breakwaters are evaluated on damping ratio of breakwater.
Piel, Alexander; Arp, Oliver; Menzel, Kristoffer; Klindworth, Markus
2007-11-01
We report on experimental observations of dust density waves in a complex (dusty) plasma under microgravity. The plasma is produced in a radio-frequency parallel-plate discharge (argon, p=15Pa, U=65Vpp). Different sizes of dust particles were used (3.4 μm and 6.4μm diameter). The low-frequency (f 11Hz) dust density waves are naturally unstable modes, which are driven by the ion flow in the plasma. Surprisingly, the wave propagation direction is aligned with the ion flow direction in the bulk plasma but becomes oblique at the boundary of the dust cloud with an inclination of 60^o with respect to the plasma boundary. The experimental results are compared with a kinetic model in the electrostatic approximation [1] and a fluid model [2]. Moreover, the role of dust surface waves is discussed. [1] M. Rosenberg, J. Vac. Sci. Technol. A 14, 631 (1996) [2] A. Piel et al, Phys. Rev. Lett. 97, 205009 (2006)
DEFF Research Database (Denmark)
Munster-Swendsen, Mikael; Calabuig, Isabel
2000-01-01
Chelostoma, empty cells, interaction, mortality, nest architecture, nest parasite, protection, Sapyga, solitary bee......Chelostoma, empty cells, interaction, mortality, nest architecture, nest parasite, protection, Sapyga, solitary bee...
BGK electron solitary waves: 1D and 3D
Directory of Open Access Journals (Sweden)
L.-J. Chen
2002-01-01
Full Text Available This paper presents new results for 1D BGK electron solitary wave (phase-space electron hole solutions and, based on the new results, extends the solutions to include the 3D electrical interaction (E ~ 1/r 2 of charged particles. Our approach for extending to 3D is to solve the nonlinear 3D Poisson and 1D Vlasov equations based on a key feature of 1D electron hole (EH solutions; the positive core of an EH is screened by electrons trapped inside the potential energy trough. This feature has not been considered in previous studies. We illustrate this key feature using an analytical model and argue that the feature is independent of any specific model. We then construct azimuthally symmetric EH solutions under conditions where electrons are highly field-aligned and ions form a uniform background along the magnetic field. Our results indicate that, for a single humped electric potential, the parallel cut of the perpendicular component of the electric field (E⊥ is unipolar and that of the parallel component (E|| bipolar, reproducing the multi-dimensional features of the solitary waves observed by the FAST satellite. Our analytical solutions presented in this article capture the 3D electric interaction and the observed features of (E|| and E⊥. The solutions predict a dependence of the parallel width-amplitude relation on the perpendicular size of EHs. This dependence can be used in conjunction with experimental data to yield an estimate of the typical perpendicular size of observed EHs; this provides important information on the perpendicular span of the source region as well as on how much electrostatic energy is transported by the solitary waves.
Eady Solitary Waves: A Theory of Type B Cyclogenesis.
Mitsudera, Humio
1994-11-01
Localized baroclinic instability in a weakly nonlinear, long-wave limit using an Eady model is studied. The resulting evolution equations have a form of the KdV type, including extra terms representing linear coupling. Baroclinic instability is triggered locally by the collision between two neutral solitary waves (one trapped at the upper boundary and the other at the lower boundary) if their incident amplitudes are sufficiently large. This characteristic is explained from the viewpoint of resonance when the relative phase speed, which depends on the amplitudes, is less than a critical value. The upper and lower disturbances grow in a coupled manner (resembling a normal-mode structure) initially, but they reverse direction slowly as the amplitudes increase, and eventually separate from each other.The motivation of this study is to investigate a type of extratropical cyclogenesis that involves a preexisting upper trough (termed as Type B development) from the viewpoint of resonant solitary waves. Two cases are of particular interest. First, the author examines a case where an upper disturbance preexists over an undisturbed low-level waveguide. The solitary waves exhibit behavior similar to that conceived by Hoskins et al. for Type B development; the lower disturbance is forced one sidedly by a preexisting upper disturbance initially, but in turn forces the latter once the former attains a sufficient amplitude, thus resulting in mutual reinforcement. Second, if a weak perturbation exists at the surface ahead of the preexisting strong upper disturbance, baroclinic instability is triggered when the two waves interact. Even though the amplitude of the lower disturbance is initially much weaker, it is intensified quickly and catches up with the amplitude of the upper disturbance, so that the coupled vertical structure resembles that of an unstable normal mode eventually. These results describe the observed behavior in Type B atmospheric cyclogenesis quite well.
En Bloc Resection of Solitary Functional Secreting Spinal Metastasis.
Goodwin, C Rory; Clarke, Michelle J; Gokaslan, Ziya L; Fisher, Charles; Laufer, Ilya; Weber, Michael H; Sciubba, Daniel M
2016-05-01
Study Design Literature review. Objective Functional secretory tumors metastatic to the spine can secrete hormones, growth factors, peptides, and/or molecules into the systemic circulation that cause distinct syndromes, clinically symptomatic effects, and/or additional morbidity and mortality. En bloc resection has a limited role in metastatic spine disease due to the current paradigm that systemic burden usually determines morbidity and mortality. Our objective is to review the literature for studies focused on en bloc resection of functionally active spinal metastasis as the primary indication. Methods A review of the PubMed literature was performed to identify studies focused on functional secreting metastatic tumors to the spinal column. We identified five cases of patients undergoing en bloc resection of spinal metastases from functional secreting tumors. Results The primary histologies of these spinal metastases were pheochromocytoma, carcinoid tumor, choriocarcinoma, and a fibroblast growth factor 23-secreting phosphaturic mesenchymal tumor. Although studies of en bloc resection for these rare tumor subtypes are confined to case reports, this surgical treatment option resulted in metabolic cures and decreased clinical symptoms postoperatively for patients diagnosed with solitary functional secretory spinal metastasis. Conclusion Although the ability to formulate comprehensive conclusions is limited, case reports demonstrate that en bloc resection may be considered as a potential surgical option for the treatment of patients diagnosed with solitary functional secretory spinal metastatic tumors. Future prospective investigations into clinical outcomes should be conducted comparing intralesional resection and en bloc resection for patients diagnosed with solitary functional secretory spinal metastasis.
SOLITARY PARAGANGLIOMA OF THE HYPOGLOSSAL NERVE: CASE REPORT.
LENUS (Irish Health Repository)
2012-02-01
SOLITARY PARAGANGLIOMA OF THE HYPOGLOSSAL NERVE:: Case Report BACKGROUND AND IMPORTANCE:: We report the case history of solitary hypoglossal paraganglioma in a 64-year-old woman. The surgical difficulties encountered in the removal of this challenging tumour are discussed with literature review. CLINICAL PRESENTATION:: A 64-year-old woman presented with a short history of dysphonia, occasional dysphagia, tinnitus, altered taste, and unilateral left sided tongue wasting. On examination there was left lower motor hypoglossal paralysis. Imaging showed a discrete enhancing lobulated mass, measuring 2cm x 2cm, in the region of the hypoglossal nerve extending into the hypoglossal canal suggestive of hypoglossal paraganglioma. A left dorsolateral sub occipital craniotomy was carried out in the sitting position. The hypoglossal nerve appeared to be enlarged and the jugular foramen was normal. Complete surgical debulking of the tumour was not attempted due to its vascular nature. The nerve was decompressed and neuropathology confirmed a low grade paraganglioma arising from the hypoglossal nerve. The patient is scheduled to receive stereotactic radiation for further management. CONCLUSION:: When a case of solitary hypoglossal paraganglioma is encountered in clinical practice, the aim of management should be mainly focussed on achieving a diagnosis and preserving the hypoglossal nerve function. If there is evidence of vascularity in the lesion noted in the MRI scan, a pre-operative angiogram should be performed with a view for embolisation.We decompressed the hypoglossal canal and achieved a good improvement in the patient\\'s symptoms. We recommend stereotactic radiosurgery for remnant and small hypoglossal tumours and regular follow up with MRI scans.
SOLITARY PARAGANGLIOMA OF THE HYPOGLOSSAL NERVE: CASE REPORT.
LENUS (Irish Health Repository)
Raza, Kazim
2011-01-25
SOLITARY PARAGANGLIOMA OF THE HYPOGLOSSAL NERVE:: Case Report BACKGROUND AND IMPORTANCE:: We report the case history of solitary hypoglossal paraganglioma in a 64-year-old woman. The surgical difficulties encountered in the removal of this challenging tumour are discussed with literature review. CLINICAL PRESENTATION:: A 64-year-old woman presented with a short history of dysphonia, occasional dysphagia, tinnitus, altered taste, and unilateral left sided tongue wasting. On examination there was left lower motor hypoglossal paralysis. Imaging showed a discrete enhancing lobulated mass, measuring 2cm x 2cm, in the region of the hypoglossal nerve extending into the hypoglossal canal suggestive of hypoglossal paraganglioma. A left dorsolateral sub occipital craniotomy was carried out in the sitting position. The hypoglossal nerve appeared to be enlarged and the jugular foramen was normal. Complete surgical debulking of the tumour was not attempted due to its vascular nature. The nerve was decompressed and neuropathology confirmed a low grade paraganglioma arising from the hypoglossal nerve. The patient is scheduled to receive stereotactic radiation for further management. CONCLUSION:: When a case of solitary hypoglossal paraganglioma is encountered in clinical practice, the aim of management should be mainly focussed on achieving a diagnosis and preserving the hypoglossal nerve function. If there is evidence of vascularity in the lesion noted in the MRI scan, a pre-operative angiogram should be performed with a view for embolisation.We decompressed the hypoglossal canal and achieved a good improvement in the patient\\'s symptoms. We recommend stereotactic radiosurgery for remnant and small hypoglossal tumours and regular follow up with MRI scans.
Research on consistency of identifying solitary pulmonary masses with CT
Institute of Scientific and Technical Information of China (English)
Qiuping Wang; Gang Niu; Yun Zhang; Yongqian Qiang; Zicheng Li; Youmin Guo
2008-01-01
Objective:To research on consistency of identifying solitary pulmonary masses with CT.Methods:Three observers with different working backgrounds in imaging diagnosis individually interpreted the same group images of solitary pulmonary mass, by 12 indexes of objective signs.The differences in interpretation resulted in ante- and post-interpretations were assessed by the x2 test.The agreement of two interpretations from the same observer was confirmed with the kappa test.A double-blind method was adopted for analysis.Results:The agreement rates of ante- and post-interpreting from the three observers were respectively 82.65%(486/588) 80.27%(472/588) and 84.86% (499/588) while their interpreting results were generally accordant without significant difference(x2 ＝ 4.975, df＝ 2,P ＝ 0.083) however there was difference between the observer 2 and observer 3(x2 ＝ 4.875, df＝ 1, P ＝ 0.027).There were five indexes with k > 0.40 of ante- and post-interpreting results of the three observers, including clarity of nodule borderline, presence of sentus, uniformity of density, existence of cavity and calcification in pathological region, among them, the agreement rate of interpreting borderline and cavity was higher(k > 0.07); the blood vessel convergence poorer(0 < k ≤ 0.40); the other six CT signs of interpretation were slightly different.Conclusion:The ability to identify solitary pulmonary mass was inconsistent, and needs to be improved further.
Breathing solitary-pulse pairs in a linearly coupled system
Dana, Brenda; Bahabad, Alon
2014-01-01
It is shown that pairs of solitary pulses (SPs) in a linearly-coupled system with opposite group-velocity dispersions form robust breathing bound states. The system can be realized by temporal-modulation coupling of SPs with different carrier frequencies propagating in the same medium, or by coupling of SPs in a dual-core waveguide. Broad SP pairs are produced in a virtually exact form by means of the variational approximation. Strong nonlinearity tends to destroy the periodic evolution of the SP pairs.
Blastomycosis presenting as solitary nodule: A rare presentation
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Ashish Dhamija
2012-01-01
Full Text Available Blastomycosis is a chronic granulomatous and suppurative mycosis, caused by Blastomyces dermatitidis, which in the great majority of cases presents as a primary pulmonary disease. Primary cutaneous blastomycosis is very rare. We present a 57-year-old female patient with a solitary, slowly progressive nodule over upper lip of 2½ months duration. Initially, differential diagnosis of cutaneous leishmaniasis, pyoderma and deep mycoses were entertained. Slit smear preparation was suspicious of deep mycotic infection which was subsequently confirmed by biopsy and culture.
Solitary Fibrous Tumor in Bladder:A Case Report
Institute of Scientific and Technical Information of China (English)
王涛; 陈瑞宝; 乔建坤; 胡涛; 刘继红; 杨为民; 叶章群
2010-01-01
Solitary fibrous tumor(SFT) in bladder is extremely rare.In this study,we reported one case of bladder SFT and reviewed the only ten cases of the disease that had been reported so far.The patient suffered from residual urine sensation and urethral pain.Cystoscopy revealed a 7-cm protruding mass at the dome of the bladder,and bladder mucosa biopsy showed normal differentiation of the bladder mucosa with a small amount of inflammatory cells.Radical resection of the tumor was performed in this patient.Patholog...
Coherent structures in wave boundary layers. Part 2. Solitary motion
DEFF Research Database (Denmark)
Sumer, B. Mutlu; Jensen, Palle Martin; Sørensen, Lone B.;
2010-01-01
in an oscillating water tunnel. Two kinds of measurements were made: bed shear stress measurements and velocity measurements. The experiments show that the solitary-motion boundary layer experiences three kinds of flow regimes as the Reynolds number is increased: (i) laminar regime; (ii) laminar regime where...... the boundary-layer flow experiences a regular array of vortex tubes near the bed over a short period of time during the deceleration stage; and (iii) transitional regime characterized with turbulent spots, revealed by single/multiple, or, sometimes, quite dense spikes in the bed shear stress traces...
A case report of reactive solitary eccrine syringofibroadenoma
Tiwary, Anup K.; Firdous, J.; Mishra, Dharmendra K.; Chaudhary, Shyam S.
2017-01-01
Eccrine syringofibroadenoma is a very rare benign tumour of acrosyringium of eccrine sweat duct. Based on the evidences of known etiological factors, two forms have been proposed; reactive and nonreactive. Reactive forms are rarer, and on even rarer occasions, trauma complicated by secondary nonspecific infections may lead to the development of reactive eccrine syringofibroadenoma, as in our case. Here, we are documenting a case of reactive solitary eccrine syringofibroadenoma in a 65-year-old male presenting with coalescing, firm, pinkish, verrucous nodules and painful deep ulceration on the right sole preceded by trauma and secondary infection. Histopathologic revelation of distinctive microscopic findings confirmed the diagnosis in our case. PMID:28217470
Metastatic melanoma mimicking solitary fibrous tumor: report of two cases.
Bekers, Elise M; van Engen-van Grunsven, Adriana C H; Groenen, Patricia J T A; Westdorp, Harm; Koornstra, Rutger H T; Bonenkamp, Johannes J; Flucke, Uta; Blokx, Willeke A M
2014-02-01
Malignant melanomas are known for their remarkable morphological variation and aberrant immunophenotype with loss of lineage-specific markers, especially in recurrences and metastases. Hot spot mutations in BRAF, NRAS, GNAQ, and GNA11 and mutations in KIT are oncogenic events in melanomas. Therefore, genotyping can be a useful ancillary diagnostic tool. We present one case each of recurrent and metastatic melanoma, both showing histological and immunohistochemical features of solitary fibrous tumor (SFT). Mutational analysis detected BRAF and NRAS mutations in the primary and secondary lesions, respectively. This result confirmed the diagnosis of recurrent/metastastic melanoma.
Experiments and computation of onshore breaking solitary waves
DEFF Research Database (Denmark)
Jensen, A.; Mayer, Stefan; Pedersen, G.K.
2005-01-01
This is a combined experimental and computational study of solitary waves that break on-shore. Velocities and accelerations are measured by a two-camera PIV technique and compared to theoretical values from an Euler model with a VOF method for the free surface. In particular, the dynamics of a so......-called collapsing breaker is scrutinized and the closure between the breaker and the beach is found to be akin to slamming. To the knowledge of the authors, no velocity measurements for this kind of breaker have been previously reported....
[A solitary neurofibroma in the parotid gland from nervus vagus].
Fagö-Olsen, Helena Anna; Hahn, Christoffer Holst
2013-03-04
A 37-year-old male, without stigmata of neurofibromatosis type 1, developed a firm mass below the right ear over several months without facial palsy. Clinical examination and ultra-sonography revealed a tumour in the parotid gland. Fine needle aspirationbiopsy was inconclusive. During complete resection, the tumour revealed an unusual anatomic location from the superficial lobe of the parotid to the deep and further into the parapharyngeal space. The pathological examination showed a solitary neurofibroma. In this case report, preoperative diagnosis, therapy and follow-up of this rare tumour in the parotid gland from n. vagus are discussed.
SOLITARY WAVES IN FINITE DEFORMATION ELASTIC CIRCULAR ROD
Institute of Scientific and Technical Information of China (English)
LIU Zhi-fang; ZHANG Shan-yuan
2006-01-01
A new nonlinear wave equation of a finite deformation elastic circular rod simultaneously introducing transverse inertia and shearing strain was derived by means of Hamilton principle. The nonlinear equation includes two nonlinear terms caused by finite deformation and double geometric dispersion effects caused by transverse inertia and transverse shearing strain. Nonlinear wave equation and corresponding truncated nonlinear wave equation were solved by the hyperbolic secant function finite expansion method. The solitary wave solutions of these nonlinear equations were obtained. The necessary condition of these solutions existence was given also.
Flow and sediment transport induced by a plunging solitary wave
DEFF Research Database (Denmark)
Sumer, B. Mutlu; Sen, M.Berke; Karagali, Ioanna
2011-01-01
, and for observation of the morphological changes. The two experimental conditions were maintained as similar as possible. The experiments showed that the complete sequence of the plunging solitary wave involves the following processes: Shoaling and wave breaking; Runup; Rundown and hydraulic jump; and Trailing wave...... affected, by as much as a factor of 2, in the runup and hydraulic jump stages. The pore-water pressure measurements showed that the sediment at (or near) the surface of the bed experiences upward-directed pressure gradient forces during the downrush phase. The magnitude of this force can reach values...
Solitary fibrous tumor arising in an intrathoracic goiter
DEFF Research Database (Denmark)
Larsen, Stine Rosenkilde; Godballe, Christian; Krogdahl, Annelise
2010-01-01
. CONCLUSION: The histological appearance and immunohistochemical reaction pattern of SFT is characteristic. The entity should be considered when dealing with a spindle cell lesion in the thyroid gland. All cases of this site of origin reported have had a benign clinical course. As only a small number of cases......BACKGROUND: Solitary fibrous tumor (SFT) is a rare spindle cell tumor most often found in the mediastinal pleura. Nineteen cases of SFT arising in the thyroid gland have been reported. We report a case of SFT of the thyroid gland with immunohistochemical and cytogenetic investigation. SUMMARY: A 58...
Solitary fibrous tumor of the orbit presenting in pregnancy
Directory of Open Access Journals (Sweden)
Das Jayanta
2009-01-01
Full Text Available A 32-year-old woman, three months pregnant, reported with the complaint of protrusion of the right eye for six months. She gave history of rapid protrusion of eyeball for the last two months along with the history of double vision for the last one month. Computer tomography (CT scan revealed a well-defined mass lesion in the intraconal space of the right orbit which was excised through a lateral orbitotomy approach. Histological examination and immunohistochemistry revealed a solitary fibrous tumor, which showed a rapid progression in pregnancy.
Dust exposure in Finnish foundries.
Siltanen, E; Koponen, M; Kokko, A; Engström, B; Reponen, J
1976-01-01
Dust measurements were made in 51 iron, 9 steel, and 8 nonferrous foundries, at which 4,316 foundrymen were working. The sampling lasted at least two entire shifts or work days continuously during various operations in each foundry. The dust samples were collected at fixed sites or in the breathing zones of the workers. The mass concentration was determined by weighing and the respirable dust fraction was separated by liquid sedimentation. The free silica content was determined by X-ray diffraction. In the study a total of 3,188 samples were collected in the foundries and 6,505 determinations were made in the laboratory. The results indicated a definite difference in the dust exposure during various operations. The highest dust exposures were found during furnace, cupola, and pouring ladle repair. During cleaning work, sand mixing, and shake-out operations excessive silica dust concentrations were also measured. The lowest dust concentrations were measured during melting and pouring operations. Moderate dust concentrations were measured during coremaking and molding operations. The results obtained during the same operations of iron and steel foundries were similar. The distribution of the workers into various exposure categories, the content of respirable dust and quartz, the correlation between respirable dust and total dust, and the correlation between respirable silica and total dust concentrations are discussed. Observations concerning dust suppression and control methods are briefly considered.
Institute of Scientific and Technical Information of China (English)
LIN Chang; ZHANG Xiu-Lian
2005-01-01
The nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation is analytically investigated by using the formally variable separation approach. New analytical solutions for the governing equation of this system have been obtained for dust acoustic waves in a dust plasma for the first time. We derive exact analytical expressions for the general case of the nonlinear dust acoustic waves in two-dimensional dust plasma with dust charge variation.
2004-01-01
[figure removed for brevity, see original site] Released 6 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth. Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms. Dust devils, small cyclonic wind storms, are common in the American Southwest and on Mars. As the dust devil moves across the surface it picks up the loose dust, leaving behind a dark track to mark its passage. These dust devil tracks are in the Argyre Basin. Image information: VIS instrument. Latitude -46.6, Longitude 317.5 East (42.5 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the
Elfgren, E; Elfgren, Erik
2003-01-01
The possibility that population III stars have reionized the Universe at redshifts greater than 6 has recently gained momentum with WMAP polarization results. Here we analyse the role of early dust produced by these stars and ejected into the intergalactic medium. We show that this dust, heated by the radiation from the same population III stars, produces a submillimetre excess. The electromagnetic spectrum of this excess is compatible with the FIRAS (Far Infrared Absolute Spectrophotometer) cosmic far infrared background. This spectrum, a Doppler spectrum times the $\
Reiss, Dennis; Fenton, Lori; Neakrase, Lynn; Zimmerman, Michael; Statella, Thiago; Whelley, Patrick; Rossi, Angelo Pio; Balme, Matthew
2016-11-01
Dust devils that leave dark- or light-toned tracks are common on Mars and they can also be found on the Earth's surface. Dust devil tracks (hereinafter DDTs) are ephemeral surface features with mostly sub-annual lifetimes. Regarding their size, DDT widths can range between ˜1 m and ˜1 km, depending on the diameter of dust devil that created the track, and DDT lengths range from a few tens of meters to several kilometers, limited by the duration and horizontal ground speed of dust devils. DDTs can be classified into three main types based on their morphology and albedo in contrast to their surroundings; all are found on both planets: (a) dark continuous DDTs, (b) dark cycloidal DDTs, and (c) bright DDTs. Dark continuous DDTs are the most common type on Mars. They are characterized by their relatively homogenous and continuous low albedo surface tracks. Based on terrestrial and martian in situ studies, these DDTs most likely form when surficial dust layers are removed to expose larger-grained substrate material (coarse sands of ≥500 μm in diameter). The exposure of larger-grained materials changes the photometric properties of the surface; hence leading to lower albedo tracks because grain size is photometrically inversely proportional to the surface reflectance. However, although not observed so far, compositional differences (i.e., color differences) might also lead to albedo contrasts when dust is removed to expose substrate materials with mineralogical differences. For dark continuous DDTs, albedo drop measurements are around 2.5 % in the wavelength range of 550-850 nm on Mars and around 0.5 % in the wavelength range from 300-1100 nm on Earth. The removal of an equivalent layer thickness around 1 μm is sufficient for the formation of visible dark continuous DDTs on Mars and Earth. The next type of DDTs, dark cycloidal DDTs, are characterized by their low albedo pattern of overlapping scallops. Terrestrial in situ studies imply that they are formed when sand
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
Using direct algebraic method,exact solitary wave solutions are performed for a class of third order nonlinear dispersive disipative partial differential equations. These solutions are obtained under certain conditions for the relationship between the coefficients of the equation. The exact solitary waves of this class are rational functions of real exponentials of kink-type solutions.
Laboratory Generation of Solitary Waves:An Inversion Technique to Improve Available Methods
Institute of Scientific and Technical Information of China (English)
A.Romano; M.Guerrini; G.Bellotti; 琚烈红
2014-01-01
Solitary waves are often used in laboratory experiments to study tsunamis propagation and interaction with coasts. However, the experimental shape of the waves may differ from the theoretical one. In this paper, a correction technique aiming at minimizing the discrepancies between the two profiles is presented. Laboratory experiments reveal their effectiveness in correcting the experimental shape of solitary waves, mainly for low nonlinearities.
Solitary Solution of Discrete mKdV Equation by Homotopy Analysis Method
Institute of Scientific and Technical Information of China (English)
XU Xi-Xiang; WANG Zhen; YANG Hong-Xiang; ZOU Li; LU Rong-Wu; ZHANG Hong-Qing
2008-01-01
In this paper, we apply homotopy analysis method to solve discrete mKdV equation and successfully obtain the bell-shaped solitary solution to mKdV equation. Comparison between our solution and the exact solution shows that homotopy analysis method is effective and validity in solving hybrid nonlinear problems, including solitary solution of difference-differential equation.
Large Amplitude Solitary Waves in a Fluid－Filled Elastic Tube
Institute of Scientific and Technical Information of China (English)
DUANWen-Shah
2003-01-01
By usign the potential method to a fluid filled elastic tube, we obtained a solitary wave solution.Compared with recluetive perturbation method, this method can be used for larger amplitude solitary waves. The result is in agreement with that of small amplitude approximation from reduetive perturbation method when the amplitude is small enough.
Large Amplitude Solitary Waves in a Fluid-Filled Elastic Tube
Institute of Scientific and Technical Information of China (English)
DUAN Wen-Shan
2003-01-01
By using the potential method to a fluid filled elastic tube, we obtained a solitary wave solution. Comparedwith reductive perturbation method, this method can be used for larger amplitude solitary waves. The result is inagreement with that of small amplitude approximation from reductive perturbation method when the amplitude is smallenough.
Solitary cysticercosis of the biceps brachii in a vegetarian: a rare and unusual pseudotumor
Energy Technology Data Exchange (ETDEWEB)
Abdelwahab, Ibrahim Fikry [Department of Radiology, New York Methodist Hospital Affiliated with Weill Medical College of Cornell University, 506 Sixth Street, Brooklyn, NY 11215 (United States); Klein, Michael J. [Department of Pathology, Mount Sinai Medical Center, 1 Gustave Levy Place, New York, NY 10029 (United States); Hermann, George [Department of Radiology, Mount Sinai Medical Center, 1 Gustave Levy Place, New York, NY 10029 (United States); Abdul-Quader, Mohammed [Department of Radiology, Columbia Presbyterian Medical Center, 177 Fort Washington Avenue, New York, NY 10032 (United States)
2003-07-01
We report a 40-year-old man with cysticercosis presenting as a solitary tumor in the biceps brachii muscle. Physical examination revealed an intramuscular mass and magnetic resonance imaging suggested a cyst. The histologic diagnosis was a cysticercus. Such solitary presentation of muscular cysticercosis is extremely rare with only a handful of sporadic reports in the literature. (orig.)
A double optical solitary wave in a nonlinear Schr(o)dinger-type equation
Institute of Scientific and Technical Information of China (English)
Yin Jiu-Li; Ding Shan-Yu
2013-01-01
A qualitative analysis method to efficiently solve the shallow wave equations is improved,so that a more complicated nonlinear Schr(o)dinger equation can be considered.By using the detailed study,some quite strange optical solitary waves are obtained in which the bright and dark optical solitary waves are allowed to coexist.
Directory of Open Access Journals (Sweden)
Kazantseva E.V.
2015-01-01
Full Text Available In a model which describes asymmetric oppositely directed nonlinear coupler it was observed in numerical simulations a phenomenon of solitary wave generation from the input constant continuous wave set at the entrance of a waveguide with negative refraction. The period of solitary wave formation decreases with increase of the continuum wave amplitude.
Vlasov Simulation of Electrostatic Solitary Structures in Multi-Component Plasmas
Umeda, Takayuki; Ashour-Abdalla, Maha; Pickett, Jolene S.; Goldstein, Melvyn L.
2012-01-01
Electrostatic solitary structures have been observed in the Earth's magnetosheath by the Cluster spacecraft. Recent theoretical work has suggested that these solitary structures are modeled by electron acoustic solitary waves existing in a four-component plasma system consisting of core electrons, two counter-streaming electron beams, and one species of background ions. In this paper, the excitation of electron acoustic waves and the formation of solitary structures are studied by means of a one-dimensional electrostatic Vlasov simulation. The present result first shows that either electron acoustic solitary waves with negative potential or electron phase-space holes with positive potential are excited in four-component plasma systems. However, these electrostatic solitary structures have longer duration times and higher wave amplitudes than the solitary structures observed in the magnetosheath. The result indicates that a high-speed and small free energy source may be needed as a fifth component. An additional simulation of a five-component plasma consisting of a stable four-component plasma and a weak electron beam shows the generation of small and fast electron phase-space holes by the bump-on-tail instability. The physical properties of the small and fast electron phase-space holes are very similar to those obtained by the previous theoretical analysis. The amplitude and duration time of solitary structures in the simulation are also in agreement with the Cluster observation.
Solitary extramedullary plasmacytoma in retroperitoneum: A case report and review of the literature
Institute of Scientific and Technical Information of China (English)
Wei Hong; Xin-Min Yu; Ming-Qiang Jiang; Bo Chen; Xin-Bao Wang; Li-Tao Yang; Yi-Ping Zhang
2009-01-01
Extramedullary plasmacytoma (EPM) is a plasma cell tumor arising outside of the bone marrow. Solitary EMP is an uncommon neoplasm and rarely occurs in the retroperitoneum and lacks distinctive clinical manifestations. We report a 26-year-old man with a solitary EMP in the retroperitoneum and discuss its clinical features, diagnosis and treatment.
Dispersal of solitary bees and bumblebees in a winter oilseed rape field
DEFF Research Database (Denmark)
Calabuig, Isabel
2000-01-01
Dispersal distributions of solitary bees and bumblebees were studied in a winter oilseed rape field. Window-traps were placed in the rape field along a line transect perpendicular to the field edge. 19 species of solitary bees were recorded and all but four species are polylectic, including...
Differential Properties of Venom Peptides and Proteins in Solitary vs. Social Hunting Wasps
Lee, Si Hyeock; Baek, Ji Hyeong; Yoon, Kyungjae Andrew
2016-01-01
The primary functions of venoms from solitary and social wasps are different. Whereas most solitary wasps sting their prey to paralyze and preserve it, without killing, as the provisions for their progeny, social wasps usually sting to defend their colonies from vertebrate predators. Such distinctive venom properties of solitary and social wasps suggest that the main venom components are likely to be different depending on the wasps’ sociality. The present paper reviews venom components and properties of the Aculeata hunting wasps, with a particular emphasis on the comparative aspects of venom compositions and properties between solitary and social wasps. Common components in both solitary and social wasp venoms include hyaluronidase, phospholipase A2, metalloendopeptidase, etc. Although it has been expected that more diverse bioactive components with the functions of prey inactivation and physiology manipulation are present in solitary wasps, available studies on venom compositions of solitary wasps are simply too scarce to generalize this notion. Nevertheless, some neurotoxic peptides (e.g., pompilidotoxin and dendrotoxin-like peptide) and proteins (e.g., insulin-like peptide binding protein) appear to be specific to solitary wasp venom. In contrast, several proteins, such as venom allergen 5 protein, venom acid phosphatase, and various phospholipases, appear to be relatively more specific to social wasp venom. Finally, putative functions of main venom components and their application are also discussed. PMID:26805885
Stability of Solitary Waves for Three Coupled Long Wave - Short Wave Interaction Equations
Borluk, H.; Erbay, S.
2009-01-01
In this paper we consider a three-component system of one dimensional long wave-short wave interaction equations. The system has two-parameter family of solitary wave solutions. We prove orbital stability of the solitary wave solutions using variational methods.
Solitary central osteoma of mandible in a geriatric patient: Report and review
Bhujbal, Ravi B.; Nayak, Ajay G.
2016-01-01
Solitary central osteomas of jaw are extremely rare lesions with only few previously documented cases. This paper reports a case of large solitary central osteoma involving mandible symphysis- parasymphysis region in an elderly female patient. A brief review of similar cases reported in the literature is also provided in this paper. Key words:Osteomas, osteogenic,bone, tumor, jaw, mandible. PMID:27034765
Electrostatic Characterization of Lunar Dust
2008-01-01
To ensure the safety and success of future lunar exploration missions, it is important to measure the toxicity of the lunar dust and its electrostatic properties. The electrostatic properties of lunar dust govern its behavior, from how the dust is deposited in an astronaut s lungs to how it contaminates equipment surfaces. NASA has identified the threat caused by lunar dust as one of the top two problems that need to be solved before returning to the Moon. To understand the electrostatic nature of lunar dust, NASA must answer the following questions: (1) how much charge can accumulate on the dust? (2) how long will the charge remain? and (3) can the dust be removed? These questions can be answered by measuring the electrostatic properties of the dust: its volume resistivity, charge decay, charge-to-mass ratio or chargeability, and dielectric properties.
Oceanic pycnocline depth retrieval from SAR imagery in the existence of solitary internal waves
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
Oceanic pycnocline depth is usually inferred from in situ measurements. It is attempted to estimate the depth remotely. As solitary internal waves occur on oceanic pycnocline and propagate along it, it is possible to retrieve the depth indirectly in virtue of the solitary internal waves. A numerical model is presented for retrieving the pycnocline depth from synthetic aperture radar (SAR) images where the solitary internal waves are visible and when ocean waters are fully stratified. This numerical model is constructed by combining the solitary internal wave model and a two-layer ocean model. It is also assumed that the observed groups of solitary internal wave packets on the SAR imagery are generated by local semidiurnal tides. A case study in the East China Sea shows a good agreement with in situ CTD (conductivity-temperature-depth) data.
Generation of internal solitary waves by frontally forced intrusions in geophysical flows.
Bourgault, Daniel; Galbraith, Peter S; Chavanne, Cédric
2016-12-06
Internal solitary waves are hump-shaped, large-amplitude waves that are physically analogous to surface waves except that they propagate within the fluid, along density steps that typically characterize the layered vertical structure of lakes, oceans and the atmosphere. As do surface waves, internal solitary waves may overturn and break, and the process is thought to provide a globally significant source of turbulent mixing and energy dissipation. Although commonly observed in geophysical fluids, the origins of internal solitary waves remain unclear. Here we report a rarely observed natural case of the birth of internal solitary waves from a frontally forced interfacial gravity current intruding into a two-layer and vertically sheared background environment. The results of the analysis carried out suggest that fronts may represent additional and unexpected sources of internal solitary waves in regions of lakes, oceans and atmospheres that are dynamically similar to the situation examined here in the Saguenay Fjord, Canada.
Divisi, Duilio; Barone, Mirko; Zaccagna, Gino; Crisci, Roberto
2017-11-01
Solitary pulmonary nodules are common radiologic findings and their detection has increased due to the introduction and improvement of diagnostics. Since a nodule can be an expression of early lung cancers, a proper classification and management are required because its treatment might lead to decreased morbidity and mortality. In this regard, prominent guidelines are available although they are characterized sometimes by discordant and misleading evidences. Furthermore, the same results of studies in the literature appear conflicting. Aim of this work is to evaluate the role of imaging through an extensive literature review but focusing on 18-fluorine fluorodeoxyglucose positron emission tomography combined with computed tomography ((18)F-FDG-PET/CT) in order to assess the limits and future perspectives of solitary pulmonary nodule characterization in early detection of lung cancer. Key messages Detection of solitary pulmonary nodules has increased. Management of solitary pulmonary nodules is still debated. Future perspectives of early solitary pulmonary nodule characterization.
Generation of internal solitary waves by frontally forced intrusions in geophysical flows
Bourgault, Daniel; Galbraith, Peter S.; Chavanne, Cédric
2016-12-01
Internal solitary waves are hump-shaped, large-amplitude waves that are physically analogous to surface waves except that they propagate within the fluid, along density steps that typically characterize the layered vertical structure of lakes, oceans and the atmosphere. As do surface waves, internal solitary waves may overturn and break, and the process is thought to provide a globally significant source of turbulent mixing and energy dissipation. Although commonly observed in geophysical fluids, the origins of internal solitary waves remain unclear. Here we report a rarely observed natural case of the birth of internal solitary waves from a frontally forced interfacial gravity current intruding into a two-layer and vertically sheared background environment. The results of the analysis carried out suggest that fronts may represent additional and unexpected sources of internal solitary waves in regions of lakes, oceans and atmospheres that are dynamically similar to the situation examined here in the Saguenay Fjord, Canada.
Measurement of Ultra-Short Solitary Electromagnetic Pulses
Directory of Open Access Journals (Sweden)
Eva Gescheidtova
2004-01-01
Full Text Available In connection with the events of the last few years and with the increased number of terrorist activities, the problem of identification and measurement of electromagnetic weapons or other systems impact occurred. Among these are also microwave sources, which can reach extensive peak power of up to Pmax = 100 MW. Solitary, in some cases several times repeated, impulses lasting from tp E <1, 60>ns, cause the destruction of semiconductor junctions. These days we can find scarcely no human activity, where semiconductor structures are not used. The problem of security support of the air traffic, transportation, computer nets, banks, national strategic data canter’s, and other applications crops up. Several types of system protection from the ultra-short electromagnetic pulses present itself, passive and active protection. The analysis of the possible measuring methods, convenient for the identification and measurement of the ultra-short solitary electromagnetic pulses in presented in this paper; some of the methods were chosen and used for practical measurement. This work is part of Research object MSM262200022 "Research of microelectronic systems".
Identification of the exploatation dust in road dust
Directory of Open Access Journals (Sweden)
B. Gajdzik
2012-01-01
Full Text Available The aim of this publication is to determine models of explore dust from vehicle brake systems and the presentationof measurement results of the exploitation dust, which is separate from road dust. The following methods and measuring devices were used: T-01M device, screen analysis, analysis of chemical composition with the use of a scanning microscope with Energy Dispersive x-ray Spectroscopy (EDS analyser. The measurements for identifying this type of dust were conducted on marked sections of roads: motorway, city road and mountain road. The explored dust was distinguished in the following car systems: brakes, clutch plates, tyres and catalytic converters.
Cylindrically symmetric dust spacetime
Senovilla, J M M; Senovilla, Jose M. M.; Vera, Raul
2000-01-01
We present an explicit exact solution of Einstein's equations for an inhomogeneous dust universe with cylindrical symmetry. The spacetime is extremely simple but nonetheless it has new surprising features. The universe is ``closed'' in the sense that the dust expands from a big-bang singularity but recollapses to a big-crunch singularity. In fact, both singularities are connected so that the whole spacetime is ``enclosed'' within a single singularity of general character. The big-bang is not simultaneous for the dust, and in fact the age of the universe as measured by the dust particles depends on the spatial position, an effect due to the inhomogeneity, and their total lifetime has no non-zero lower limit. Part of the big-crunch singularity is naked. The metric depends on a parameter and contains flat spacetime as a non-singular particular case. For appropriate values of the parameter the spacetime is a small perturbation of Minkowski spacetime. This seems to indicate that flat spacetime may be unstable agai...
Cylindrically symmetric dust spacetime
Senovilla, José M. M.
2000-07-01
We present an explicit exact solution of Einstein's equations for an inhomogeneous dust universe with cylindrical symmetry. The spacetime is extremely simple but nonetheless it has surprising new features. The universe is `closed' in the sense that the dust expands from a big-bang singularity but recollapses to a big-crunch singularity. In fact, both singularities are connected so that the whole spacetime is `enclosed' within a single singularity of general character. The big-bang is not simultaneous for the dust, and in fact the age of the universe as measured by the dust particles depends on the spatial position, an effect due to the inhomogeneity, and their total lifetime has no non-zero lower limit. Part of the big-crunch singularity is naked. The metric depends on a parameter and contains flat spacetime as a non-singular particular case. For appropriate values of the parameter the spacetime is a small perturbation of Minkowski spacetime. This seems to indicate that flat spacetime may be unstable against some global non-vacuum perturbations.
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
NASA's Stardust spacecraft ended its seven-year voyage January 15 after a safe landing on earth, bringing back a capsule of comet particles and samples of interstellar dust that exceeded the loftiest of expectations of mission scientists. The ensuing studies of the cosmic treasure are expected to shed light on the origins of the solar system and earth itself.
Horton, W.; Miura, H.; Onishchenko, O.; Couedel, L.; Arnas, C.; Escarguel, A.; Benkadda, S.; Fedun, V.
2016-06-01
A self-consistent hydrodynamic model for the solar heating-driven onset of a dust devil vortex is derived and analyzed. The toroidal flows and vertical velocity fields are driven by an instability that arises from the inversion of the mass density stratification produced by solar heating of the sandy surface soil. The nonlinear dynamics in the primary temperature gradient-driven vertical airflows drives a secondary toroidal vortex flow through a parametric interaction in the nonlinear structures. While an external tangential shear flow may initiate energy transfer to the toroidal vortex flow, the nonlinear interactions dominate the transfer of vertical-radial flows into a fast toroidal flow. This secondary flow has a vertical vorticity, while the primary thermal gradient-driven flow produces the toroidal vorticity. Simulations for the complex nonlinear structure are carried out with the passive convection of sand as test particles. Triboelectric charging modeling of the dust is used to estimate the charging of the sand particles. Parameters for a Dust Devil laboratory experiment are proposed considering various working gases and dust particle parameters. The nonlinear dynamics of the toroidal flow driven by the temperature gradient is of generic interest for both neutral gases and plasmas.
2002-01-01
(Released 13 May 2002) The Science The rugged, arcuate rim of the 90 km crater Reuyl dominates this THEMIS image. Reuyl crater is at the southern edge of a region known to be blanketed in thick dust based on its high albedo (brightness) and low thermal inertia values. This thick mantle of dust creates the appearance of snow covered mountains in the image. Like snow accumulation on Earth, Martian dust can become so thick that it eventually slides down the face of steep slopes, creating runaway avalanches of dust. In the center of this image about 1/3 of the way down is evidence of this phenomenon. A few dozen dark streaks can be seen on the bright, sunlit slopes of the crater rim. The narrow streaks extend downslope following the local topography in a manner very similar to snow avalanches on Earth. But unlike their terrestrial counterparts, no accumulation occurs at the bottom. The dust particles are so small that they are easily launched into the thin atmosphere where they remain suspended and ultimately blow away. The apparent darkness of the avalanche scars is due to the presence of relatively dark underlying material that becomes exposed following the passage of the avalanche. Over time, new dust deposition occurs, brightening the scars until they fade into the background. Although dark slope streaks had been observed in Viking mission images, a clear understanding of this dynamic phenomenon wasn't possible until the much higher resolution images from the Mars Global Surveyor MOC camera revealed the details. MOC images also showed that new avalanches have occurred during the time MGS has been in orbit. THEMIS images will allow additional mapping of their distribution and frequency, contributing new insights about Martian dust avalanches. The Story The stiff peaks in this image might remind you of the Alps here on Earth, but they really outline the choppy edge of a large Martian crater over 50 miles wide (seen in the context image at right). While these aren
Dust-acoustic solitons in quantum plasma with kappa-distributed ions
Indian Academy of Sciences (India)
Mehran Shahmansouri
2013-02-01
Arbitrary amplitude dust-acoustic (DA) solitary waves in an unmagnetized and collisionless quantum dusty plasma comprising cold dust particles, kappa ()-distributed ions and degenerate electrons are investigated. The influence of suprathermality and quantum effects on the linear dispersion relation of DA waves is investigated. Then, the effect of -distributed ions and degenerate electrons on the existence domain of solitons is discussed in the space of (, ). The comparison of the existence domain for higher and lower values of shows that suprathermality results in propagation of solitons with lower values of Mach number, and the quantum effects, lead to a higher values of Mach number. The existence domain of solitons for nondegenerate -distributed electrons is considered for comparison with effect of degenerate electrons. Also, we found that the Sagdeev potential well becomes deeper and wider as $_{F-i}$ decreases, as for lower values, the influence of quantum effects on the Sagdeev pseudopotential profile is smaller.
Dust processing in elliptical galaxies
Hirashita, Hiroyuki; Villaume, Alexa; Srinivasan, Sundar
2015-01-01
We reconsider the origin and processing of dust in elliptical galaxies. We theoretically formulate the evolution of grain size distribution, taking into account dust supply from asymptotic giant branch (AGB) stars and dust destruction by sputtering in the hot interstellar medium (ISM), whose temperature evolution is treated by including two cooling paths: gas emission and dust emission (i.e. gas cooling and dust cooling). With our new full treatment of grain size distribution, we confirm that dust destruction by sputtering is too efficient to explain the observed dust abundance even if AGB stars continue to supply dust grains, and that, except for the case where the initial dust-to-gas ratio in the hot gas is as high as $\\sim 0.01$, dust cooling is negligible compared with gas cooling. However, we show that, contrary to previous expectations, cooling does not help to protect the dust; rather, the sputtering efficiency is raised by the gas compression as a result of cooling. We additionally consider grain grow...
2004-01-01
[figure removed for brevity, see original site] Released 9 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth. Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms. In our final dust devil image we are again looking at the southern hemisphere of Mars. These tracks occur mainly on the northeast side of the topographic ridges. Of course, there are many exceptions, which makes understanding the dynamics that initiate the actual dust devil cyclone difficult. Image information: VIS instrument. Latitude -47.6, Longitude 317.3 East (42.7 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed
2004-01-01
[figure removed for brevity, see original site] Released 8 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth. Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms. These dust devil tracks occur on the northern plains of Mars. The majority of the surface seen in the image has been affected by the passage of dust devils. Image information: VIS instrument. Latitude -54.6, Longitude 79.3 East (280.7 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are
Distribution of dust during two dust storms in Iceland
Ösp Magnúsdóttir, Agnes; Dagsson-Waldhauserova, Pavla; Arnalds, Ólafur; Ólafsson, Haraldur
2017-04-01
Particulate matter mass concentrations and size fractions of PM1, PM2.5, PM4, PM10, and PM15 measured in transversal horizontal profile of two dust storms in southwestern Iceland are presented. Images from a camera network were used to estimate the visibility and spatial extent of measured dust events. Numerical simulations were used to calculate the total dust flux from the sources as 180,000 and 280,000 tons for each storm. The mean PM15 concentrations inside of the dust plumes varied from 10 to 1600 ?g?m?3 (PM10 = 7 to 583 ?g?m?3). The mean PM1 concentrations were 97-241 ?g?m?3 with a maximum of 261 ?g?m?3 for the first storm. The PM1/PM2.5 ratios of >0.9 and PM1/PM10 ratios of 0.34-0.63 show that suspension of volcanic materials in Iceland causes air pollution with extremely high PM1 concentrations, similar to polluted urban areas in Europe or Asia. Icelandic volcanic dust consists of a higher proportion of submicron particles compared to crustal dust. Both dust storms occurred in relatively densely inhabited areas of Iceland. First results on size partitioning of Icelandic dust presented here should challenge health authorities to enhance research in relation to dust and shows the need for public dust warning systems.