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Artykuły w czasopismach na temat „Electron acoustic waves”

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Data publikacji: 6 września 2023

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1

Lakhina, G. S., S. V. Singh, A. P. Kakad, F. Verheest i R. Bharuthram. "Study of nonlinear ion- and electron-acoustic waves in multi-component space plasmas". Nonlinear Processes in Geophysics 15, nr 6 (27.11.2008): 903–13. http://dx.doi.org/10.5194/npg-15-903-2008.

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Abstract. Large amplitude ion-acoustic and electron-acoustic waves in an unmagnetized multi-component plasma system consisting of cold background electrons and ions, a hot electron beam and a hot ion beam are studied using Sagdeev pseudo-potential technique. Three types of solitary waves, namely, slow ion-acoustic, ion-acoustic and electron-acoustic solitons are found provided the Mach numbers exceed the critical values. The slow ion-acoustic solitons have the smallest critical Mach numbers, whereas the electron-acoustic solitons have the largest critical Mach numbers. For the plasma parameters considered here, both type of ion-acoustic solitons have positive potential whereas the electron-acoustic solitons can have either positive or negative potential depending on the fractional number density of the cold electrons relative to that of the ions (or total electrons) number density. For a fixed Mach number, increases in the beam speeds of either hot electrons or hot ions can lead to reduction in the amplitudes of the ion-and electron-acoustic solitons. However, the presence of hot electron and hot ion beams have no effect on the amplitudes of slow ion-acoustic modes. Possible application of this model to the electrostatic solitary waves (ESWs) observed in the plasma sheet boundary layer is discussed.

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2

Saleem, H., i G. Murtaza. "Nonlinear excitation of electron-acoustic waves". Journal of Plasma Physics 36, nr 2 (październik 1986): 295–99. http://dx.doi.org/10.1017/s0022377800011764.

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It is shown that for a plasma with ion temperature greater than electron temperature, an extraordinary electro-magnetic pump wave can parametrically decay into upper-hybrid and electron-acoustic oscillations. The threshold power flux and the growth rate of the instability are obtained. Comparison of our investigation with an earlier work and its possible application to a mirror machine is pointed out.

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3

Sonner, Maximilian M., Farhad Khosravi, Lisa Janker, Daniel Rudolph, Gregor Koblmüller, Zubin Jacob i Hubert J. Krenner. "Ultrafast electron cycloids driven by the transverse spin of a surface acoustic wave". Science Advances 7, nr 31 (lipiec 2021): eabf7414. http://dx.doi.org/10.1126/sciadv.abf7414.

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Spin-momentum locking is a universal wave phenomenon promising for applications in electronics and photonics. In acoustics, Lord Rayleigh showed that surface acoustic waves exhibit a characteristic elliptical particle motion strikingly similar to spin-momentum locking. Although these waves have become one of the few phononic technologies of industrial relevance, the observation of their transverse spin remained an open challenge. Here, we observe the full spin dynamics by detecting ultrafast electron cycloids driven by the gyrating electric field produced by a surface acoustic wave propagating on a slab of lithium niobate. A tubular quantum well wrapped around a nanowire serves as an ultrafast sensor tracking the full cyclic motion of electrons. Our acousto-optoelectrical approach opens previously unknown directions in the merged fields of nanoacoustics, nanophotonics, and nanoelectronics for future exploration.

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4

Hafez, M. G., M. R. Talukder i M. Hossain Ali. "Two-Dimensional Nonlinear Propagation of Ion Acoustic Waves through KPB and KP Equations in Weakly Relativistic Plasmas". Advances in Mathematical Physics 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/9352148.

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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.

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5

Andreev, Pavel A. "Spin-electron-acoustic waves and solitons in high-density degenerate relativistic plasmas". Physics of Plasmas 29, nr 12 (grudzień 2022): 122102. http://dx.doi.org/10.1063/5.0114914.

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Spin-electron-acoustic waves (sometimes called spin-plasmons) can be found in degenerate electron gases if spin-up electrons and spin-down electrons move relatively each other. Here, we suggest relativistic hydrodynamics with separate spin evolution, which allows us to study linear and nonlinear spin-electron-acoustic waves, including the spin-electron-acoustic solitons. The presented hydrodynamic model is the corresponding generalization of the relativistic hydrodynamic model with the average reverse gamma factor evolution, which consists of equations for evolution of the following functions: the partial concentrations (for spin-up electrons and spin-down electrons), the partial velocity fields, the partial average reverse relativistic gamma factors, and the partial flux of the reverse relativistic gamma factors. We find that the relativistic effects decrease the phase velocity of spin-electron-acoustic waves. Numerical analysis of the changes of dispersion curves of the Langmuir wave, spin-electron-acoustic wave, and ion-acoustic wave under the change of the spin polarization of electrons is presented. It is demonstrated that dispersion curves of the Langmuir wave and spin-electron-acoustic wave get closer to each other in the relativistic limit. Spin dependence of the amplitude and width of the relativistic spin-electron-acoustic soliton is demonstrated as well. Reformation of the bright soliton of potential of the electric field into the dark soliton under the influence of the relativistic effects is found.

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6

Nejoh, YN. "Positron-acoustic Waves in an Electron - Positron Plasma with an Electron Beam". Australian Journal of Physics 49, nr 5 (1996): 967. http://dx.doi.org/10.1071/ph960967.

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The nonlinear wave structures of large-amplitude positron-acoustic waves are studied in an electron–positron plasma with an electron beam. We present the region where positron-acoustic waves exist by analysing the structure of the pseudopotential. The region depends sensitively on the positron density, the positron temperature and the electron beam temperature. It is shown that the maximum amplitude of the wave decreases as the positron temperature increases, and the region of positron-acoustic waves spreads as the positron . Temperature increases. The present theory is applicable to analysing hirge-amplitude positron-acoustic waves associated with positrons which may occur in interplanetary space.

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7

Shukla, P. K., M. A. Hellberg i L. Stenflo. "Modulation of electron-acoustic waves". Journal of Atmospheric and Solar-Terrestrial Physics 65, nr 3 (luty 2003): 355–58. http://dx.doi.org/10.1016/s1364-6826(02)00334-6.

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8

Sahu, Biswajit, i Mouloud Tribeche. "Nonplanar electron acoustic shock waves". Advances in Space Research 51, nr 12 (czerwiec 2013): 2353–57. http://dx.doi.org/10.1016/j.asr.2013.01.030.

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9

Singh, S. V., i G. S. Lakhina. "Electron acoustic solitary waves with non-thermal distribution of electrons". Nonlinear Processes in Geophysics 11, nr 2 (14.04.2004): 275–79. http://dx.doi.org/10.5194/npg-11-275-2004.

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Abstract. Electron-acoustic solitary waves are studied in an unmagnetized plasma consisting of non-thermally distributed electrons, fluid cold electrons and ions. The Sagdeev pseudo-potential technique is used to carry out the analysis. The presence of non-thermal electrons modifies the parametric region where electron acoustic solitons can exist. For parameters representative of auroral zone field lines, the electron acoustic solitons do not exist when either α > 0.225 or Tc/Th > 0.142, where α is the fractional non-thermal electron density, and Tc (Th) represents the temperature of cold (hot) electrons. Further, for these parameters, the simple model predicts negatively charged potential structures. Inclusion of an electron beam in the model may provide the positive potential solitary structures.

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10

Treumann, R. A., i W. Baumjohann. "Plasma wave mediated attractive potentials: a prerequisite for electron compound formation". Annales Geophysicae 32, nr 8 (22.08.2014): 975–89. http://dx.doi.org/10.5194/angeo-32-975-2014.

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Abstract. Coagulation of electrons to form macro-electrons or compounds in high temperature plasma is not generally expected to occur. Here we investigate, based on earlier work, the possibility for such electron compound formation (non-quantum "pairing") mediated in the presence of various kinds of plasma waves via the generation of attractive electrostatic potentials, the necessary condition for coagulation. We confirm the possibility of production of attractive potential forces in ion- and electron-acoustic waves, pointing out the importance of the former and expected consequences. While electron-acoustic waves presumably do not play any role, ion-acoustic waves may potentially contribute to formation of heavy electron compounds. Lower-hybrid waves also mediate compound formation but under different conditions. Buneman modes which evolve from strong currents may also potentially cause non-quantum "pairing" among cavity-/hole-trapped electrons constituting a heavy electron component that populates electron holes. The number densities are, however, expected to be very small and thus not viable for justification of macro-particles. All these processes are found to potentially generate cold compound populations. If such electron compounds are produced by the attractive forces, the forces provide a mechanism of cooling a small group of resonant electrons, loosely spoken, corresponding to classical condensation.

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11

Morris, Paul J., Artem Bohdan, Martin S. Weidl i Martin Pohl. "Preacceleration in the Electron Foreshock. I. Electron Acoustic Waves". Astrophysical Journal 931, nr 2 (1.06.2022): 129. http://dx.doi.org/10.3847/1538-4357/ac69c7.

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Abstract To undergo diffusive shock acceleration, electrons need to be preaccelerated to increase their energies by several orders of magnitude, else their gyroradii will be smaller than the finite width of the shock. In oblique shocks, where the upstream magnetic field orientation is neither parallel nor perpendicular to the shock normal, electrons can escape to the shock upstream, modifying the shock foot to a region called the electron foreshock. To determine the preacceleration in this region, we undertake particle-in-cell simulations of oblique shocks while varying the obliquity and in-plane angles. We show that while the proportion of reflected electrons is negligible for θ Bn = 74.°3, it increases to R ∼ 5% for θ Bn = 30°, and that, via the electron acoustic instability, these electrons power electrostatic waves upstream with energy density proportional to R 0.6 and a wavelength ≈2λ se, where λ se is the electron skin length. While the initial reflection mechanism is typically a combination of shock-surfing acceleration and magnetic mirroring, we show that once the electrostatic waves have been generated upstream, they themselves can increase the momenta of upstream electrons parallel to the magnetic field. In ≲1% of cases, upstream electrons are prematurely turned away from the shock and never injected downstream. In contrast, a similar fraction is rescattered back toward the shock after reflection, reinteracts with the shock with energies much greater than thermal, and crosses into the downstream.

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12

Devanandhan, S., S. V. Singh i G. S. Lakhina. "Electron acoustic solitary waves with kappa-distributed electrons". Physica Scripta 84, nr 2 (1.08.2011): 025507. http://dx.doi.org/10.1088/0031-8949/84/02/025507.

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13

Lakhina, Gurbax Singh, Satyavir Singh, Thekkeyil Sreeraj, Selvaraj Devanandhan i Rajith Rubia. "A Mechanism for Large-Amplitude Parallel Electrostatic Waves Observed at the Magnetopause". Plasma 6, nr 2 (1.06.2023): 345–61. http://dx.doi.org/10.3390/plasma6020024.

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Large-amplitude electrostatic waves propagating parallel to the background magnetic field have been observed at the Earth’s magnetopause by the Magnetospheric Multiscale (MMS) spacecraft. These waves are observed in the region where there is an intermixing of magnetosheath and magnetospheric plasmas. The plasma in the intermixing region is modeled as a five-component plasma consisting of three types of electrons, namely, two counterstreaming hot electron beams and cold electrons, and two types of ions, namely, cold background protons and a hot proton beam. Sagdeev pseudo-potential technique is used to study the parallel propagating nonlinear electrostatic solitary structures. The model predicts four types of modes, namely, slow ion-acoustic mode, fast ion-acoustic mode, slow electron-acoustic mode and fast electron-acoustic modes. Except the fast ion-acoustic mode, all other modes support solitons. Whereas slow ion-acoustic solitons have positive potentials, both slow and fast electron-acoustic solitons have negative potentials. For the case of 4% cold electron density, the slow ion-acoustic solitons have electric field ∼(40–120) mV m−1. The fast Fourier transforms (FFT) of slow ion-acoustic solitons produce broadband frequency spectra having peaks between ∼100 Hz to 1000 Hz. These theoretical predictions are in good agreement with the observations. The slow and fast electron-acoustic solitons could be relevant in explaining the low-intensity high (>1 kHz) frequency waves which are also observed at the same time.

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14

Liu, Yong, i Jiang Zhou. "The envelope soliton for the nonlinear interaction of Langmuir waves with electron acoustic waves in the Earth's inner magnetosphere". Physics of Plasmas 29, nr 9 (wrzesień 2022): 092302. http://dx.doi.org/10.1063/5.0096999.

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The nonlinear coupling of Langmuir waves with electron-acoustic waves is investigated using the kinetic theory, where the hot electron component is modeled by the kappa distribution with an exponential cutoff at high energy tail, i.e., the cutoff kappa distribution. The one dimensional structure of envelope Langmuir solitons is analyzed by the numerical calculation with parameters typical of the Earth's inner magnetosphere. In the case of hot electrons with a cutoff kappa distribution, envelope Langmuir solitons have larger width and slower speed than that in the case of hot electrons with a Maxwellian distribution. The envelop Langmuir soliton with density depletion obtained in the Earth's inner magnetosphere propagates at a speed lower than the electron-acoustic velocity. At a given amplitude of electrostatic field, the envelope Langmuir soltions have a speed comparable with the ones of electron-acoustic wave solitons, but a wider scale in the case of hot electrons with a cutoff kappa distribution.

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15

Webb, G. M., R. H. Burrows, X. Ao i G. P. Zank. "Ion acoustic traveling waves". Journal of Plasma Physics 80, nr 2 (15.01.2014): 147–71. http://dx.doi.org/10.1017/s0022377813001013.

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AbstractModels for traveling 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 traveling 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–proton or an electron–positron plasma). Besides its intrinsic interest, the integral equation solution provides a useful analytical test for numerical codes that include a proton–electron mass ratio as a fundamental constant, such as for particle in cell (PIC) codes. The integral equation is used to delineate the physical characteristics of ion acoustic traveling waves consisting of hot electron and cold proton fluids.

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16

Yu, M. Y., P. K. Shukla i R. S. B. Ong. "Scattering of electromagnetic waves by electron acoustic waves". Planetary and Space Science 35, nr 3 (marzec 1987): 295–98. http://dx.doi.org/10.1016/0032-0633(87)90156-5.

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17

Mace, R. L., M. A. Hellberg, R. Bharuthram i S. Baboolal. "Electron-acoustic solitons in a weakly relativistic plasma". Journal of Plasma Physics 47, nr 1 (luty 1992): 61–74. http://dx.doi.org/10.1017/s0022377800024089.

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Weakly relativistic electron-acoustic solitons are investigated in a two-electron-component plasma whose cool electrons form a relativistic beam. A general Korteweg-de Vries (KdV) equation is derived, in the small-|ø| domain, for a plasma consisting of an arbitrary number of relativistically streaming fluid components and a hot Boltzmann component. This equation is then applied to the specific case of electron-acoustic waves. In addition, the fully nonlinear system of fluid and Poisson equations is integrated to yield electron-acoustic solitons of arbitrary amplitude. It is shown that relativistic beam effects on electron-acoustic solitons significantly increase the soliton amplitude beyond its non-relativistic value. For intermediate- to large-amplitude solitons, a finite cool-electron temperature is found to destroy the balance between nonlinearity and dispersion, yielding soliton break-up. Also, only rarefactive electronacoustic soliton solutions of our equations are found, even though the relativistic beam provides a positive contribution to the nonlinear coefficient of the KdV equation, describing relativistic, nonlinear electron-acoustic waves.

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18

Bharuthram, R., S. V. Singh, S. K. Maharaj, S. Moolla, I. J. Lazarus, R. V. Reddy i G. S. Lakhina. "Do nonlinear waves evolve in a universal manner in dusty and other plasma environments?" Journal of Plasma Physics 80, nr 6 (14.07.2014): 825–32. http://dx.doi.org/10.1017/s0022377814000427.

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Using a fluid theory approach, this article provides a comparative study on the evolution of nonlinear waves in dusty plasmas, as well as other plasma environments, viz electron-ion, and electron-positron plasmas. Where applicable, relevance to satellite measurements is pointed out. A range of nonlinear waves from low frequency (ion acoustic and ion cyclotron waves), high frequency (electron acoustic and electron cyclotron waves) in electron-ion plasmas, ultra-low frequency (dust acoustic and dust cyclotron waves) in dusty plasmas and in electron-positron plasmas are discussed. Depending upon the plasma parameters, saw-tooth and bipolar structures are shown to evolve.

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19

Welna, F., i J. B. Wang. "Electron Transport via Surface Acoustic Waves". Journal of Computational and Theoretical Nanoscience 7, nr 9 (1.09.2010): 1737–46. http://dx.doi.org/10.1166/jctn.2010.1538.

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20

Mamun, A. A., P. K. Shukla i L. Stenflo. "Obliquely propagating electron-acoustic solitary waves". Physics of Plasmas 9, nr 4 (kwiecień 2002): 1474–77. http://dx.doi.org/10.1063/1.1462635.

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21

Maccari, Attilio. "Interacting dromions for electron acoustic waves". Chaos, Solitons & Fractals 15, nr 1 (styczeń 2003): 141–52. http://dx.doi.org/10.1016/s0960-0779(02)00124-8.

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22

Valentini, Francesco, Thomas M. O’Neil i Daniel H. E. Dubin. "Excitation of nonlinear electron acoustic waves". Physics of Plasmas 13, nr 5 (maj 2006): 052303. http://dx.doi.org/10.1063/1.2198467.

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23

Aman-ur-Rehman, S. Ali, S. A. Khan i K. Shahzad. "Twisted electron-acoustic waves in plasmas". Physics of Plasmas 23, nr 8 (sierpień 2016): 082122. http://dx.doi.org/10.1063/1.4961927.

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24

Valentini, F., T. M. O’Neil i D. H. E. Dubin. "Decay instability of electron acoustic waves". Communications in Nonlinear Science and Numerical Simulation 13, nr 1 (luty 2008): 215–20. http://dx.doi.org/10.1016/j.cnsns.2007.04.012.

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25

Bansal, Sona, Munish Aggarwal i Tarsem Singh Gill. "Nonplanar Electron - Acoustic Shock Waves with Superthermal Hot Electrons". Brazilian Journal of Physics 48, nr 6 (18.09.2018): 638–44. http://dx.doi.org/10.1007/s13538-018-0602-8.

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26

Mozer, F. S., S. D. Bale, C. A. Cattell, J. Halekas, I. Y. Vasko, J. L. Verniero i P. J. Kellogg. "Core Electron Heating by Triggered Ion Acoustic Waves in the Solar Wind". Astrophysical Journal Letters 927, nr 1 (1.03.2022): L15. http://dx.doi.org/10.3847/2041-8213/ac5520.

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Abstract Perihelion passes on Parker Solar Probe orbits 6–9 have been studied to show that solar wind core electrons emerged from 15 solar radii with a temperature of 55 ± 5 eV, independent of the solar wind speed, which varied from 300 to 800 km s−1. After leaving 15 solar radii and in the absence of triggered ion acoustic waves at greater distances, the core electron temperature varied with radial distance, R, in solar radii, as 1900R −4/3 eV because of cooling produced by the adiabatic expansion. The coefficient, 1900, reproduces the minimum core electron perpendicular temperature observed during the 25 days of observation. In the presence of triggered ion acoustic waves, the core electrons were isotropically heated as much as a factor of two above the minimum temperature, 1900R −4/3 eV. Triggered ion acoustic waves were the only waves observed in coincidence with the core electron heating. They are the dominant wave mode at frequencies greater than 100 Hz at solar distances between 15 and 30 solar radii.

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27

Franceschi, J. L., R. Murillo, A. Bastié, M. Ez-Zejjari, H. El Abdary i N. Boughanmi. "In Situ Scanning Electron Acoustic Microscopy". Proceedings, annual meeting, Electron Microscopy Society of America 48, nr 1 (12.08.1990): 408–9. http://dx.doi.org/10.1017/s0424820100180793.

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A mini scanning electron microscope, the MEBIS [1] (“Microscope Electronique à Balayage In situ”) is used to inspect “in situ” bulk specimens. The electron-optical column which has been made small and light, can be placed just over the sample. With a specially designed control circuitry, a chopped electron beam is used as a source of thermoelastic waves at the surface of specimen. The induced thermal and ultrasonic waves are used for detection and, by combining this acoustic signal with the scanned electron beam, imaging of the subsurface is possible.The accelerating potential used is 10 kV and the equivalent source of thermoelastic waves is less than one micrometre in metals. Below the megahertz range for the chopped beam (frequency f), the wavelength of sound λa is greater than that of the thermal waves λg. Approximately, only thermal waves determines the spatial resolution [2]. These waves are damped with an experimental decay dT = Cte.f−1/2, and the spatial resolution is similar to dT, typically five micrometres in metals for the beam modulation frequency of 100 kHz, with linear signal detection [3]. Above the MHz range, submicronic spatial resolution is possible. But the sensitivity is also a function of the frequency. The signal to noise ratio (S/N) is proportionnal to f−1 (low frequency). A compromise must be made between S/N ratio and satisfactory spatial resolution, since for bulk specimens the signal decays with the thickness [4].

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28

El-Hanbaly, A. M., E. K. El-Shewy, A. I. Kassem i H. F. Darweesh. "Nonlinear Electron Acoustic Waves in Dissipative Plasma with Superthermal Electrons". Applied Physics Research 8, nr 1 (29.01.2016): 64. http://dx.doi.org/10.5539/apr.v8n1p64.

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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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29

Chakrabarti, Nikhil, i Sudip Sengupta. "Nonlinear interaction of electron plasma waves with electron acoustic waves in plasmas". Physics of Plasmas 16, nr 7 (lipiec 2009): 072311. http://dx.doi.org/10.1063/1.3191722.

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30

Barnes, C. H. W., J. M. Shilton i A. M. Robinson. "Quantum computation using electrons trapped by surface acoustic waves". Quantum Information and Computation 1, Special (grudzień 2001): 96–101. http://dx.doi.org/10.26421/qic1.s-9.

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We outline a set of ideas for implementing a quantum processor based on technology used in surface acoustic wave (SAW) single-electron transport devices. These devices allow single electrons to be captured from a two-dimensional electron gas by a SAW. We discuss how these devices can be adapted to capture electrons in pure spin states and how both single and two-qubit gates can be constructed. We give designs for readout gates and discuss possible sources of error and decoherence.

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31

Shi, Run, i Jun Liang. "Mode conversion from kinetic Alfvén waves to modified electron acoustic waves". Physics of Plasmas 29, nr 8 (sierpień 2022): 082104. http://dx.doi.org/10.1063/5.0093193.

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Possible mode conversion from kinetic Alfvén wave to modified electron acoustic wave is examined based on a multi-fluid model involving two electron populations. The mode conversion transpires when a kinetic Alfvén wave propagates through a transition between a hot-electron-dominant region and a cold-electron-dominant region. It is shown that the mode conversion and the kinetic Alfvén wave reflection depend strongly on the hot electron inertial length, the hot electron temperature, and the perpendicular wavelength. The results suggest that such conversion is ubiquitous whenever a steep gradient of electron temperature exists, for example, in the planetary auroral acceleration regions or at the boundary of the solar corona.

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32

McKENZIE, JAMES F. "Wave dynamics of an electrojet: generalized Farley–Buneman instability". Journal of Plasma Physics 73, nr 5 (październik 2007): 701–13. http://dx.doi.org/10.1017/s002237780600612x.

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AbstractIn this paper we generalize the classical Farley–Buneman (FB) instability to include space-charge effects and finite electron inertia. The former effect makes the ion-acoustic wave dispersive with the usual resonance appearing at the ion plasma frequency, but other than that the structure of the FB instability remains intact. However, the inclusion of the latter, finite electron inertia, gives rise to the propagating electron-cyclotron mode, albeit modified by collisions. In the presence of differential electron streaming relative to the ions, the interaction between this mode, attempting to propagate against the stream, but convected forward by the stream, and a forward propagating ion-acoustic mode, gives rise to a new instability distinct from the FB instability. The process may be thought of in terms of the coupling between negative energy waves (electron-cyclotron waves attempting to propagate against the stream) and positive energy waves (forward propagating ion-acoustic waves). In principle, the instability simply requires super-ion acoustic streaming electrons and the corresponding growth rates are of the order of one half of the lower hybrid frequency, which are faster than the corresponding FB growth rates. For conditions appropriate to the middle day-side E-region this instability excites a narrow band of frequencies just below the ion plasma frequency. Its role in the generation of electrojet irregularities may be as important as the classical FB instability.

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33

Nejoh, Y. N. "Effects of Positron Density and Temperature on Large Amplitude Ion-acoustic Waves in an Electron - Positron - Ion Plasma". Australian Journal of Physics 50, nr 2 (1997): 309. http://dx.doi.org/10.1071/p96064.

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The nonlinear wave structures of large amplitude ion-acoustic waves are studied in a plasma with positrons. We have presented the region of existence of the ion-acoustic waves by analysing the structure of the pseudopotential. The region of existence sensitively depends on the positron to electron density ratio, the ion to electron mass ratio and the positron to electron temperature ratio. It is shown that the maximum Mach number increases as the positron temperature increases and the region of existence of the ion-acoustic waves spreads as the positron temperature increases. The present theory is applicable to analyse large amplitude ion-acoustic waves associated with positrons which may occur in space plasmas.

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34

Tamang, Jharna, i Asit Saha. "Dynamical Behavior of Supernonlinear Positron-Acoustic Periodic Waves and Chaos in Nonextensive Electron-Positron-Ion Plasmas". Zeitschrift für Naturforschung A 74, nr 6 (26.06.2019): 499–511. http://dx.doi.org/10.1515/zna-2018-0476.

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AbstractPropagation of nonlinear and supernonlinear positron-acoustic periodic waves is examined in an electron-positron-ion plasma composed of static positive ions, mobile cold positrons, and q-nonextensive electrons and hot positrons. Employing the phase plane theory of planar dynamical systems, all qualitatively different phase portraits that include nonlinear positron-acoustic homoclinic orbit, nonlinear positron-acoustic periodic orbit, supernonlinear positron-acoustic homoclinic orbit, and supernonlinear positron-acoustic periodic orbit are demonstrated subjected to the parameters $q,{\mu_{1}},{\mu_{2}},{\sigma_{1}},{\sigma_{2}}$, and V. The nonlinear and supernonlinear positron-acoustic periodic wave solutions are reported for different situations through numerical computations. It is observed that the nonextensive parameter (q) acts as a controlling parameter in the dynamic motion of nonlinear and supernonlinear positron-acoustic periodic waves. The dynamic motions for the positron-acoustic traveling waves with the influence of an extrinsic periodic force are investigated through distinct qualitative approaches, such as phase portrait analysis, sensitivity analysis, time series analysis, and Poincaré section. The results of this paper may be applicable in understanding nonlinear, supernonlinear positron-acoustic periodic waves, and their chaotic motion in space plasma environments.

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35

Albalawi, Wedad, Rabia Jahangir, Waqas Masood, Sadah A. Alkhateeb i Samir A. El-Tantawy. "Electron-Acoustic (Un)Modulated Structures in a Plasma Having (r, q)-Distributed Electrons: Solitons, Super Rogue Waves, and Breathers". Symmetry 13, nr 11 (27.10.2021): 2029. http://dx.doi.org/10.3390/sym13112029.

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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.

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36

Borhanian, Jafar, i Mehran Shahmansouri. "Spherical electron acoustic solitary waves in plasma with suprathermal electrons". Astrophysics and Space Science 342, nr 2 (16.06.2012): 401–6. http://dx.doi.org/10.1007/s10509-012-1137-z.

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37

Demiray, Hilmi. "Modulation of Electron-Acoustic Waves in a Plasma with Vortex Electron Distribution". International Journal of Nonlinear Sciences and Numerical Simulation 16, nr 2 (1.04.2015): 61–66. http://dx.doi.org/10.1515/ijnsns-2014-0017.

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AbstractIn the present work, employing a one-dimensional model of a plasma composed of a cold electron fluid, hot electrons obeying a trapped/vortex-like distribution and stationary ions, we study the amplitude modulation of electron-acoustic waves by use of the conventional reductive perturbation method. Employing the field equations with fractional power type of nonlinearity, we obtained the nonlinear Schrödinger equation as the evolution equation of the same order of nonlinearity. Seeking a harmonic wave solution with progressive wave amplitude to the evolution equation it is found that the NLS equation with fractional power assumes envelope type of solitary waves.

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38

Mace, R. L., i M. A. Hellberg. "On the existence of weak stationary electron-acoustic double layers". Journal of Plasma Physics 49, nr 2 (kwiecień 1993): 283–93. http://dx.doi.org/10.1017/s0022377800016998.

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The recent interest in the electron-acoustic wave as a source of broad-band electrostatic noise in the terrestrial magnetosphere makes it interesting to ask whether it can support stationary electrostatic double layers. We investigate this problem in a fluid plasma composed of cool ions, cool electrons and a hot Boltzmann electron component – which is known to support electron-acoustic waves. Although a formal application of the reductive perturbation technique to our dynamical equations leads to an mKdV equation for electron-acoustic waves, it is found that within the present physical model the consistency conditions and required ordering of the coefficients cannot be satisfied simultaneously for reasonable parameter values. As a consequence, it is shown that the neglect of the φ(2) term in deriving the mKdV equation is unjustified under general circumstances, and furthermore that the cubic nonlinearity introduced by the mKdV equation is negligible when compared with this term. Finally, we are led to conclude that stationary, weak electron-acoustic double layers cannot exist in such a plasma.

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39

Pakzad, H. R., K. Javidan i P. Eslami. "Electron acoustic waves in atmospheric magnetized plasma". Physica Scripta 95, nr 4 (13.02.2020): 045605. http://dx.doi.org/10.1088/1402-4896/ab5ffc.

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40

Andreev, Pavel A., i S. V. Kolesnikov. "Oblique propagating extraordinary spin-electron acoustic waves". Physics of Plasmas 25, nr 10 (październik 2018): 102115. http://dx.doi.org/10.1063/1.5047485.

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Kakad, A. P., S. V. Singh, R. V. Reddy, G. S. Lakhina, S. G. Tagare i F. Verheest. "Generation mechanism for electron acoustic solitary waves". Physics of Plasmas 14, nr 5 (maj 2007): 052305. http://dx.doi.org/10.1063/1.2732176.

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Anderegg, F., C. F. Driscoll, D. H. E. Dubin, T. M. O’Neil i F. Valentini. "Electron acoustic waves in pure ion plasmas". Physics of Plasmas 16, nr 5 (maj 2009): 055705. http://dx.doi.org/10.1063/1.3099646.

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Sah, O. P., i J. Manta. "Nonlinear electron-acoustic waves in quantum plasma". Physics of Plasmas 16, nr 3 (marzec 2009): 032304. http://dx.doi.org/10.1063/1.3080741.

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Nejoh, Yasunori. "Large-amplitude ion-acoustic waves in a plasma with a relativistic electron beam". Journal of Plasma Physics 56, nr 1 (sierpień 1996): 67–76. http://dx.doi.org/10.1017/s0022377800019097.

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Nonlinear wave structures of large-amplitude ion-acoustic waves in a plasma with a relativistic electron beam are studied using the pseudopotential method. The region of existence of large-amplitude ion-acoustic waves is examined, and it is shown that the condition for their existence depends sensitively on parameters such as the relativistic effect of the electron beam, the ion temperature, the electrostatic potential and the electron beam density. It turns out that the region of existence spreads as the relativistic effect (Mach number) increases and the ion temperature decreases. New properties of large-amplitude ion-acoustic waves in a plasma with a relativistic electron beam are predicted.

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45

Thapa, Shiva Bikram, Suresh Basnet i Raju Khanal. "Dust charge fluctuation and ion acoustic wave propagation in dusty plasma with q-nonextensive hot and Maxwellian cold electrons". AIP Advances 12, nr 8 (1.08.2022): 085205. http://dx.doi.org/10.1063/5.0100914.

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We have employed the self-consistent kinetic theory to study the linear dispersion relation of ion acoustic waves in a four-component plasma consisting of nonextensive hot electrons, Maxwellian cold electrons, positive ions, and dust particles. The dust charging process with the modified ion acoustic wave damping, as well as its unstable mode, has been graphically illustrated. It is found that the dust charging mechanism depends on the density of hot electrons, the degree of nonextensive electron distribution, and the temperature ratio of hot to cold electrons. It is shown that the damping and instability rates of ion acoustic waves due to dust charge fluctuations explicitly depend on the choice of electron distribution and the magnitude of dusty plasma parameters. In addition, we have studied the ion acoustic Landau damping in the absence of dust particles. It is found that the weak damping region broadens, while the strong damping region shrinks and is shifted toward the short wavelength region for the increase in the temperature ratio of hot to cold electrons.

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46

Mehdipoor, Mostafa, i Mehdi Asri. "Physical aspects of cnoidal waves in non-thermal electron-beam plasma systems". Physica Scripta 97, nr 3 (23.02.2022): 035602. http://dx.doi.org/10.1088/1402-4896/ac5487.

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Abstract The effects of electron beam and non-thermal electrons on ion-acoustic cnoidal waves (IACWs) structure in a two-fluid plasma system are investigated. A Kappa-Cairns type distribution is assumed for the background electrons. The Korteweg–de Vries (K-dV) equation is obtained by employing reductive perturbation technique and the analytical solution of K-dV equation is derived by employing the Sagdeev pseudo-potential approach. It is seen that in the presence of the electron beam, four modes can exist in this plasma model. In this study, it is observed that only two modes are real in all cases. Furthermore, it is found that the characteristics of the ion-acoustic cnoidal wave depend strongly on the electron beam parameters (via ν and U 0 ) as well as the non-thermal indexes for the plasma electrons (via κ and α ).

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47

Che, Haihong, Melvyn L. Goldstein, Patrick H. Diamond i Roald Z. Sagdeev. "How electron two-stream instability drives cyclic Langmuir collapse and continuous coherent emission". Proceedings of the National Academy of Sciences 114, nr 7 (30.01.2017): 1502–7. http://dx.doi.org/10.1073/pnas.1614055114.

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Continuous plasma coherent emission is maintained by repetitive Langmuir collapse driven by the nonlinear evolution of a strong electron two-stream instability. The Langmuir waves are modulated by solitary waves in the linear stage and electrostatic whistler waves in the nonlinear stage. Modulational instability leads to Langmuir collapse and electron heating that fills in cavitons. The high pressure is released via excitation of a short-wavelength ion acoustic mode that is damped by electrons and reexcites small-scale Langmuir waves; this process closes a feedback loop that maintains the continuous coherent emission.

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Rufai, Odutayo R., George V. Khazanov i S. V. Singh. "Finite amplitude electron-acoustic waves in the electron diffusion region". Results in Physics 24 (maj 2021): 104041. http://dx.doi.org/10.1016/j.rinp.2021.104041.

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Bharuthram, R., S. S. Misthry i M. Y. Yu. "Electron acoustic surface waves in a two‐electron component plasma". Physics of Fluids B: Plasma Physics 5, nr 12 (grudzień 1993): 4502–4. http://dx.doi.org/10.1063/1.860567.

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Sotnikov, V. I., D. Schriver, M. Ashour-Abdalla, J. Ernstmeyer i N. Myers. "Excitation of electron acoustic waves by a gyrating electron beam". Journal of Geophysical Research 100, A10 (1995): 19765. http://dx.doi.org/10.1029/95ja00900.

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