scholarly journals Electrostatic shock properties inferred from AKR fine structure

2003 ◽  
Vol 10 (1/2) ◽  
pp. 87-92 ◽  
Author(s):  
R. Pottelette ◽  
R. A. Treumann ◽  
M. Berthomier ◽  
J. Jasperse
Keyword(s):  
Electric Fields ◽  
Acoustic Waves ◽  
Sagdeev Potential ◽  
Plasma Parameters ◽  
Fluid Approximation ◽  
Auroral Kilometric Radiation ◽  
Ion Acoustic ◽  
Electron Holes ◽  
Spectral Frequency ◽  
Electron Acoustic

Abstract. The auroral kilometric radiation (AKR) consists of a large number of fast drifting elementary radiation events that have been interpreted as travelling electron holes resulting from the nonlinear evolution of electron-acoustic waves. The elementary radiation structures sometimes become reflected or trapped in slowly drifting larger structures where the parallel electric fields are located. These latter features have spectral frequency drifts which can be interpreted in terms of the propagation of shock-like disturbances along the auroral field line at velocities near the ion-acoustic speed. The amplitude, speed, and shock width of such localized ion-acoustic shocks are determined here in the fluid approximation from the Sagdeev potential, assuming realistic plasma parameters. It is emphasized that the electrostatic potentials of such nonlinear structures contribute to auroral acceleration.

scholarly journals Electron-Acoustic (Un)Modulated Structures in a Plasma Having (r, q)-Distributed Electrons: Solitons, Super Rogue Waves, and Breathers

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2029
Author(s):  
Wedad Albalawi ◽  
Rabia Jahangir ◽  
Waqas Masood ◽  
Sadah A. Alkhateeb ◽  
Samir A. El-Tantawy
Keyword(s):  
Acoustic Waves ◽  
Rogue Waves ◽  
Distribution Functions ◽  
Sagdeev Potential ◽  
Plasma Parameters ◽  
Positive Ions ◽  
Modulated Structures ◽  
Existence Domain ◽  
Unmagnetized Plasma ◽  
Electron Acoustic

The propagation of electron-acoustic waves (EAWs) in an unmagnetized plasma, comprising (r,q)-distributed hot electrons, cold inertial electrons, and stationary positive ions, is investigated. Both the unmodulated and modulated EAWs, such as solitary waves, rogue waves (RWs), and breathers are discussed. The Sagdeev potential approach is employed to determine the existence domain of electron acoustic solitary structures and study the perfectly symmetric planar nonlinear unmodulated structures. Moreover, the nonlinear Schrödinger equation (NLSE) is derived and its modulated solutions, including first order RWs (Peregrine soliton), higher-order RWs (super RWs), and breathers (Akhmediev breathers and Kuznetsov–Ma soliton) are presented. The effects of plasma parameters and, in particular, the effects of spectral indices r and q, of distribution functions on the characteristics of both unmodulated and modulated EAWs, are examined in detail. In a limited cases, the (r,q) distribution is compared with Maxwellian and kappa distributions. The present investigation may be beneficial to comprehend and predict the modulated and unmodulated electron acoustic structures in laboratory and space plasmas.

scholarly journals Spiky parallel electrostatic ion cyclotron and ion acoustic waves

2002 ◽  
Vol 9 (1) ◽  
pp. 25-29 ◽  
Author(s):  
R. V. Reddy ◽  
G. S. Lakhina ◽  
N. Singh ◽  
R. Bharuthram
Keyword(s):  
Electric Fields ◽  
Acoustic Waves ◽  
Rest Frame ◽  
Wave Form ◽  
Ion Acoustic Waves ◽  
Parallel Propagation ◽  
Wave Phase Velocity ◽  
Ion Acoustic ◽  
Ion Cyclotron ◽  
Field Aligned Current

Abstract. One of the interesting observations from the FAST satellite is the detection of strong spiky waveforms in the parallel electric field in association with ion cyclotron oscillations in the perpendicular electric fields. We report here an analytical model of the coupled nonlinear ion cyclotron and ion-acoustic waves, which could explain the observations. Using the fluid equations for the plasma consisting of warm electrons and cold ions, a nonlinear wave equation is derived in the rest frame of the propagating wave for any direction of propagation oblique to the ambient magnetic field. The equilibrium bulk flow of ions is also included in the model to mimic the field-aligned current. Depending on the wave Mach number M defined by M = V/Cs with V and Cs being the wave phase velocity and ion-acoustic speed, respectively, we find a range of solutions varying from a sinusoidal wave form for small amplitudes and low M to sawtooth and highly spiky waveforms for nearly parallel propagation. The results from the model are compared with the satellite observations.

scholarly journals Effects of Boundary and Electron Inertia on the Ion Acoustic Wave in a Plasma: A Pseudopotential Approach

1998 ◽  
Vol 51 (1) ◽  
pp. 113 ◽  
Author(s):  
K. K. Mondal ◽  
S. N. Paul ◽  
A. Roy Chowdhury
Keyword(s):  
Acoustic Waves ◽  
Finite Geometry ◽  
Cylindrical Domain ◽  
Plasma Parameters ◽  
Ion Acoustic Waves ◽  
Ion Acoustic Wave ◽  
Electron Inertia ◽  
Ion Acoustic ◽  
Pseudopotential Approach ◽  
Range Of Values

A pseudopotential approach is used to analyse the propagation of ion-acoustic waves in a plasma bounded by a cylindrical domain. The effect of the finite geometry is displayed both analytically and numerically. The phase velocity of the wave is determined and its variation is studied with respect to the plasma parameters. It is observed that the pseudopotential shows a wide variation of shape due to the imposition of a finite boundary condition. It is shown that if the other parameters are kept within a certain range of values, then the trapping of particles is favoured when the presence of the boundary is taken into account.

Ion acoustic waves in expanding strongly coupled plasmas

2013 ◽  
Vol 79 (6) ◽  
pp. 1063-1066 ◽  
Author(s):  
J. T. MENDONÇA ◽  
N. SHUKLA ◽  
D. P. RESENDES ◽  
A. SERBETO
Keyword(s):  
Acoustic Waves ◽  
Temporal Change ◽  
Wave Mode ◽  
Mode Structure ◽  
Plasma Parameters ◽  
Ion Acoustic Waves ◽  
Strongly Coupled ◽  
Ultracold Plasmas ◽  
Ion Acoustic ◽  
Coupled Plasmas

AbstractWe consider the excitation and dispersion of ion acoustic waves in expanding ultracold plasmas, taking into account the influence of boundary conditions. A cylindrical plasma geometry is assumed. We show that temporal changes in the medium lead to a wave frequency shift, associated with an evolving radial and standing wave mode structure, and to the temporal change of the background plasma parameters. A non-collisional model for the cylindrical geometry is also proposed.

scholarly journals Collapsible and Spiky Wave for Dust Acoustic Waves in Dusty Plasmas

2019 ◽  
Vol 7 (2) ◽  
pp. 81-92
Author(s):  
Ranjit K Kalita ◽  
Jnanjyoti Sarma
Keyword(s):  
Mach Number ◽  
Acoustic Waves ◽  
Energy Equation ◽  
Dusty Plasmas ◽  
Sagdeev Potential ◽  
Plasma Parameters ◽  
Dust Acoustic Waves ◽  
Dust Acoustic ◽  
Arbitrary Amplitude ◽  
Standard Values

In multicomponent dusty plasma, the Sagdeev Potential (SP) approach is employed to formulate the Energy Equation for arbitrary amplitude dust acoustic waves (DAWs), where an amount of electrons is trapped in potential well. The dependence of amplitude and width of the solitons of Sagdeev Potential on plasma parameters is widely discussed. The range of Mach number has determined for solitary waves (SWs) with the help of critical Mach number. The solution of the Energy Equation obtained, has been discussed by expanding the expression for SP in the higher terms of φ . The different solutions of Energy Equation give us SWs, breakable waves, collapsible waves and SWs with spiky and explosive nature. The role of temperature ratio on the transformation of SWs to collapsible waves is discussed. With the help of standard values of plasma parameters relevant to such plasma environment, the results so obtained, are discussed. These results may help us to explain the nature of SWs in different astrophysical situations.

scholarly journals Nonlinear Ion-acoustic Waves, Ion Holes, and Electron Holes in the Near-Sun Solar Wind

2021 ◽  
Vol 911 (2) ◽  
pp. 89
Author(s):  
F. S. Mozer ◽  
J. W. Bonnell ◽  
E. L. M. Hanson ◽  
L. C. Gasque ◽  
I. Y. Vasko
Keyword(s):  
Solar Wind ◽  
Acoustic Waves ◽  
Ion Acoustic Waves ◽  
Ion Acoustic ◽  
Electron Holes

scholarly journals Nonlinear Waveforms for Ion-Acoustic Waves in Weakly Relativistic Plasma of Warm Ion-Fluid and Isothermal Electrons

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
S. A. El-Wakil ◽  
Essam M. Abulwafa ◽  
E. K. El-Shewy ◽  
H. G. Abdelwahed ◽  
Hamdi M. Abd-El-Hamid
Keyword(s):  
Acoustic Waves ◽  
Kdv Equation ◽  
Algebraic Method ◽  
Finite Amplitude ◽  
Reductive Perturbation Method ◽  
Relativistic Plasma ◽  
Plasma Parameters ◽  
Ion Acoustic Waves ◽  
Ion Acoustic ◽  
Weakly Relativistic Plasma

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.

scholarly journals Generation of Low-Frequency Kinetic Waves at the Footpoints of Pre-Flare Coronal Loops

Solar Physics ◽  
2020 ◽  
Vol 295 (12) ◽  
Author(s):  
Alexandr Kryshtal ◽  
Anna Voitsekhovska ◽  
Oleg Cheremnykh ◽  
Istvan Ballai ◽  
Gary Verth ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Low Frequency ◽  
Small Scale ◽  
Plasma Parameters ◽  
Ion Acoustic Waves ◽  
Frequency Wave ◽  
Electric And Magnetic Fields ◽  
Ion Acoustic ◽  
Flare Process ◽  
Semi Empirical

AbstractIn this study we discuss the excitation of low-frequency plasma waves in the lower-middle chromosphere region of loop footpoints for the case when the plasma can be considered to be in a pre-flare state. It is shown that among the well-known semi-empirical models of the solar atmosphere, only the VAL (F) model together with a particular set of basic plasma parameters and amplitudes of the electric and magnetic fields supports generation of low-frequency wave instability. Our results show that it is possible to predict the onset of the flare process in the active region by using the interaction of kinetic Alfvén and kinetic ion-acoustic waves, which are solutions of the derived dispersion equation. The VAL (F) model allows situations when the main source of the aforementioned instability can be a sub-Dreicer electric field and drift plasma movements due to presence of spatial inhomogeneities. We also show that the generation of kinetic Alfvén and kinetic ion-acoustic waves can occur both, in plasma with a purely Coulomb conductivity and in the presence of small-scale Bernstein turbulence. The excitation of the small amplitude kinetic waves due to the development of low threshold instability in plasma with relatively low values of the magnetic field strength is also discussed.

scholarly journals Particle Energization in Stochastic Double Layers

1985 ◽  
Vol 107 ◽  
pp. 125-129
Author(s):  
William Lotko
Keyword(s):  
Electric Fields ◽  
Acoustic Waves ◽  
Diffusion Processes ◽  
Computer Experiments ◽  
Double Layers ◽  
Ion Temperature ◽  
Ion Drift ◽  
Ion Acoustic ◽  
Relative Electron ◽  
Ion Acoustic Double Layers

Electrostatic turbulence develops in current carrying plasmas when the relative electron-ion drift exceeds the critical value for laminar current flow. Recent 2D computer experiments (Barnes, 1982) indicate that many weak ion acoustic double layers form in such turbulence when the plasma is strongly magnetized (ωce ≳ ωpe), the electron/ion temperature ratio is large (≳10), and the relative electron-ion drift is comparable to or less than the electron thermal speed. The double layers emerge from the incoherent spectrum of electrostatic ion cyclotron and ion acoustic waves as intense localized electric field structures propagating subsonically relative to the ion bulk flow. The occurrence of weak ion acoustic double layers, excited by field-aligned currents in the Earth's auroral regions, has also been reported from in situ spacecraft measurements (Temerin et al., 1982). An important question concerns the effect of these coherent electric fields on plasma transport properties such as bulk heating and acceleration. For example, one might expect nonlinear diffusion processes, manifested as distinct nonthermal features in the particle spectra, to accompany the quasilinear diffusion of ions as they traverse turbulent regions in space. This idea motivates the work presented here.

scholarly journals Nonlinear Electron Acoustic Waves in Dissipative Plasma with Superthermal Electrons

2016 ◽  
Vol 8 (1) ◽  
pp. 64 ◽  
Author(s):  
A. M. El-Hanbaly ◽  
E. K. El-Shewy ◽  
A. I. Kassem ◽  
H. F. Darweesh
Keyword(s):  
Shock Waves ◽  
Acoustic Waves ◽  
Inertial Confinement Fusion ◽  
Collisionless Plasma ◽  
Homogeneous System ◽  
Travelling Wave ◽  
Reductive Perturbation Method ◽  
Inertial Confinement ◽  
Plasma Parameters ◽  
Electron Acoustic

The nonlinear properties of small amplitude electron-acoustic ( EA) solitary and shock waves in a homogeneous system of unmagnetized collisionless plasma consisted of a cold electron fluid and superthermal hot electrons obeying superthermal distribution, and stationary ions have been investigated. A reductive perturbation method was employed to obtain the Kadomstev-Petviashvili-Burgers (KP-Brugers) equation. Some solutions of physical interest are obtained. These solutions are related to soliton, monotonic and oscillatory shock waves and their behaviour are shown graphically. The formation of these solutions depends crucially on the value of the Burgers term and the plasma parameters as well. By using the tangent hyperbolic (tanh) method, another interesting type of solution which is a combination between shock and soliton waves is obtained . The topology of phase portrait and potential diagram of the KP-Brugers equation is investigated.The advantage of using this method is that one can predict different classes of the travelling wave solutions according to different phase orbits. The obtained results may be helpful in better understanding of waves propagation in various space plasma environments as well as in inertial confinement fusion laboratory plasmas.

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