Artykuły w czasopismach: „Quasi-electrostatic waves”

1

Moradi, Afshin. "Longitudinal quasi-electrostatic waves in hyperbolic metasurfaces". Physics Letters A 391 (marzec 2021): 127103. http://dx.doi.org/10.1016/j.physleta.2020.127103.

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Sazhin, S. S. "Whistler-mode polarization in a hot anisotropic plasma". Journal of Plasma Physics 34, nr 2 (październik 1985): 213–26. http://dx.doi.org/10.1017/s0022377800002804.

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Polarization of whistler-mode waves in a hot anisotropic plasma is considered in the two limiting cases of quasi-longitudinal and quasi-electrostatic propagation. It is pointed out that electron thermal motion never influences the phase of the propagating waves; the polarization of whistler-mode waves propagating along the magnetic field is totally independent of electron thermal motion. The deformation of polarization (in both electric and magnetic fields), of obliquely propagating whistler-mode waves could be, in principle, observed in magnetospheric conditions and thus could be used to estimate electron temperature and anisotropy. This deformation seems to be especially pronounced for the electric field polarization of quasi-electrostatic waves.

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3

Arshad, Kashif, M. Lazar i S. Poedts. "Quasi-electrostatic twisted waves in Lorentzian dusty plasmas". Planetary and Space Science 156 (lipiec 2018): 139–46. http://dx.doi.org/10.1016/j.pss.2017.10.013.

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4

Stewart, G. A. "Nonlinear electrostatic waves in equal-mass plasmas". Journal of Plasma Physics 50, nr 3 (grudzień 1993): 521–36. http://dx.doi.org/10.1017/s0022377800017311.

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A study is made of electrostatic waves in a cold equal-mass plasma. Numerical simulation reveals that cold equal-mass plasmas are fundamentally unstable to such oscillations, in contrast to the behaviour of these waves in electron-ion plasmas. A quasi-linear analysis of the problem is performed and an analytic solution found that duplicates the early evolution of the plasma.

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5

Krasovsky, V. L., H. Matsumoto i Y. Omura. "On the three-dimensional configuration of electrostatic solitary waves". Nonlinear Processes in Geophysics 11, nr 3 (2.07.2004): 313–18. http://dx.doi.org/10.5194/npg-11-313-2004.

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Abstract. The simplest models of the electrostatic solitary waves observed by the Geotail spacecraft in the magnetosphere are developed proceeding from the concept of electron phase space holes. The technique to construct the models is based on an approximate quasi-one-dimensional description of the electron dynamics and three-dimensional analysis of the electrostatic structure of the localized wave perturbations. It is shown that the Vlasov-Poisson set of equations admits a wide diversity of model solutions of different geometry, including spatial configurations of the electrostatic potential similar to those revealed by Geotail and other spacecraft in space plasmas.

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Perraut, S., A. Roux, F. Darrouzet, C. de Villedary, M. Mogilevsky i F. Lefeuvre. "ULF wave measurements onboard the Interball auroral probe". Annales Geophysicae 16, nr 9 (30.09.1998): 1105–16. http://dx.doi.org/10.1007/s00585-998-1105-7.

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Abstract. The IESP experiment implemented onboard the Interball auroral probe measures the six components (3B, 3E) of the waves in the ULF range: 0.1–10 Hz and from time to time 0–30 Hz. Two different kinds of waves have been observed in the auroral region at altitudes between 10 000 and 20 000 km: (1) electrostatic emissions which consist of quasi-monochromatic structures with frequencies above the oxygen gyrofrequency, superimposed on a wide band signal interpreted as a Doppler broadening, (2) electromagnetic wide band spectrum fluctuations. These emissions are interpreted as current-driven electromagnetic or electrostatic ion cyclotron waves. The electromagnetic/electrostatic character is controlled by the plasma parameter βi and by the O+ concentration.Key words. Magnetospheric physics · Auroral phenomena · Plasma waves and instabilities · Interball Auroral probe

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7

Lundin, B., C. Krafft, G. Matthieussent, F. Jiricek, J. Shmilauer i P. Triska. "Excitation of VLF quasi-electrostatic oscillations in the ionospheric plasma". Annales Geophysicae 14, nr 1 (31.01.1996): 27–32. http://dx.doi.org/10.1007/s00585-996-0027-5.

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Abstract. A numerical solution of the dispersion equation for electromagnetic waves in a hot magnetized collisionless plasma has shown that, in a current-free ionospheric plasma, the distortion of the electron distribution function reproducing the downward flow of a thermal electron component and the compensating upward flow of the suprathermal electrons, which are responsible for the resulting heat flux, can destabilize quasi-electrostatic ion sound waves. The numerical analysis, performed with ion densities and electron temperature taken from the data recorded by the Interkosmos-24 (IK-24, Aktivny) satellite, is compared with a VLF spectrum registered at the same time on board. This spectrum shows a wide frequency band emission below the local ion plasma frequency. The direction of the electron heat flux inherent to the assumed model of VLF emission generation is discussed

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8

Tsuchimoto, M., T. Honma i K. Miya. "Dispersion relations of toroidal plasma surface waves in quasi-electrostatic state". IEEE Transactions on Plasma Science 19, nr 2 (kwiecień 1991): 428–32. http://dx.doi.org/10.1109/27.106842.

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9

Agapitov, O. V., A. V. Artemyev, D. Mourenas, V. Krasnoselskikh, J. Bonnell, O. Le Contel, C. M. Cully i V. Angelopoulos. "The quasi-electrostatic mode of chorus waves and electron nonlinear acceleration". Journal of Geophysical Research: Space Physics 119, nr 3 (marzec 2014): 1606–26. http://dx.doi.org/10.1002/2013ja019223.

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Oks, Eugene, Elisabeth Dalimier i Paulo Angelo. "A Supersensitive Method for Spectroscopic Diagnostics of Electrostatic Waves in Magnetized Plasmas". Plasma 4, nr 4 (10.12.2021): 780–88. http://dx.doi.org/10.3390/plasma4040040.

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For relatively strong magnetic fields, hydrogen atoms can have delocalized bound states of almost macroscopic dimensions. Therefore, such states are characterized by a Giant Electric Dipole Moment (GEDM), thus making them very sensitive to an external electric field. We considered the manifestations of the GEDM states in hydrogen spectral line profiles in the presence of a quasimonochromatic electrostatic wave of a frequency ω in a plasma. We demonstrated that in this situation, hydrogen spectral lines can exhibit quasi-satellites, which are the envelopes of Blochinzew-type satellites. We showed that the distinctive feature of such quasi-satellites is that their peak intensity is located at the same distance from the line center (in the frequency scale) for all hydrogen spectral lines, the distance being significantly greater than the wave frequency ω. At the absence of the GEDM (and for relatively strong electrostatic waves), the maxima of the satellite envelopes would be at different distances from the line center for different hydrogen lines. We demonstrated that this effect would constitute a supersensitive diagnostic method for measuring the amplitude of electrostatic waves in plasmas down to ~10 V/cm or even lower.

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11

Sazhin, S. S., i E. M. Sazhina. "Some particular cases of oblique whistler-mode propagation in a hot anisotropic plasma". Journal of Plasma Physics 40, nr 1 (sierpień 1988): 69–85. http://dx.doi.org/10.1017/s002237780001312x.

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Explicit formulae for the refractive index describing oblique whistler-mode propagation at frequencies corresponding to ξ1 = −φ ≡ −0·924 (but |ξn| ≫ 1 when n ≠ 1), ξ0 = φ (but |ξn| ≫ 1 when n ≠ 0) and ξ0 = −ξ1 = φ (where ξn ≡ (ω − nΩ)/k‖w‖ are the arguments of the plasma dispersion function) are derived and analysed for two limiting cases of quasi-longitudinal and quasi-electrostatic propagation of the waves.

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Kamaletdinov, S. R., I. Y. Vasko, A. V. Artemyev, R. Wang i F. S. Mozer. "Quantifying electron scattering by electrostatic solitary waves in the Earth's bow shock". Physics of Plasmas 29, nr 8 (sierpień 2022): 082301. http://dx.doi.org/10.1063/5.0097611.

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The electrostatic fluctuations are always present in the Earth's bow shock at frequencies above about 100 Hz, but the effects of this wave activity on electron dynamics have not been quantified yet. In this paper, we quantify electron pitch-angle scattering by electrostatic solitary waves, which make up a substantial part of the electrostatic fluctuations in the Earth's bow shock and were recently shown to be predominantly ion holes. We present analytical estimates and test-particle simulations of electron pitch-angle scattering by ion holes typical of the Earth's bow shock and conclude that this scattering can be rather well quantified within the quasi-linear theory. We use the observed distributions of ion hole parameters to estimate pitch-angle scattering rates by the ensemble of ion holes typical of the Earth's bow shock. We use the recently proposed theory of stochastic shock drift acceleration to show that pitch-angle scattering of electrons by the electrostatic fluctuations can keep electrons in the shock transition region long enough to support acceleration of thermal electrons by a factor of a few tens, that is up to a few hundred eV. Importantly, the electrostatic fluctuations can be more efficient in pitch-angle scattering of [Formula: see text] keV electrons, than typically observed whistler waves.

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13

Shklyar, D. R., i E. E. Titova. "Proton interaction with quasi-electrostatic whistler mode waves in an inhomogeneous plasma (magnetosphere)". Geomagnetism and Aeronomy 57, nr 1 (styczeń 2017): 24–31. http://dx.doi.org/10.1134/s0016793217010121.

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14

Liao, B., J. R. Benbrook, E. A. Bering, G. J. Byrne, J. R. Theall, Louis J. Lanzerotti i Carol G. Maclennan. "Balloon observations of nightside Pc 5 quasi-electrostatic waves above the South Pole". Journal of Geophysical Research 99, A3 (1994): 3879. http://dx.doi.org/10.1029/93ja02753.

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MENDONÇA, J. T., J. E. RIBEIRO i P. K. SHUKLA. "Wave kinetic description of quantum pair plasmas". Journal of Plasma Physics 74, nr 1 (luty 2008): 91–97. http://dx.doi.org/10.1017/s0022377807006587.

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AbstractThe dispersion relation for a quantum pair plasma is derived, by using a wave kinetic description. A general form of the kinetic dispersion relation for electrostatic waves in a two-component quantum plasma is established. The particular case of an electron–positron pair plasma is considered in detail. Exact expressions for Landau damping are derived, and the quasi-classical limit is discussed.

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Bryant, D. A., i G. M. Courtier. "Electrostatic double layers as auroral particle accelerators – a problem". Annales Geophysicae 33, nr 4 (24.04.2015): 481–82. http://dx.doi.org/10.5194/angeo-33-481-2015.

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Abstract. A search of the Annales Geophysicae database shows that double layers and other quasi-static electric potential structures have been invoked hundreds of times since the year 2000 as being the agents of auroral electron acceleration. This is despite the fact that energy transfer by conservative fields has been known for some 200 years to be impossible. Attention is drawn to a long-standing interpretation of the acceleration process in terms of the dynamic fields of electrostatic waves.

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17

McKenzie, J. F., i M. K. Dougherty. "Electrostatic Rossby-type ion plasma waves". Journal of Plasma Physics 39, nr 1 (luty 1988): 103–14. http://dx.doi.org/10.1017/s0022377800012885.

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It is shown that a plasma in which the background magnetic field varies in a direction perpendicular to its line of action can support ‘Rossby-type’ electrostatic waves at frequencies very much less than the ion gyrofrequency. The intrinsic wave propagation mechanism at work is structurally similar to that in the atmospheric Rossby wave, which comes about from fluid perturbations being in quasi-geostrophic equilibrium (i.e. the Coriolis force nearly balances the pressure gradient) and the latitudinal variation of the vertical component of rotational frequency vector (the β-effect) so that the time rate of change of the vertical component of the fluid vorticity is equal to the northward transport of the planetary vorticity. In a plasma this ‘geostrophic balance’ arises from the near-vanishing of the Lorentz force on the ion motion while the β-effect is provided by the transverse spatial variation of the ambient magnetic field. Unlike the atmosphere, however, such a magnetized plasma is capable of supporting two distinct types of Rossby wave. The interesting dispersive and anisotropic features of these waves are revealed by the properties of their wave operators and described in terms of the geometry of their wavenumber surfaces. Since these surfaces intersect, inhomogeneity or nonlinearity will give rise to strong mode-mode coupling in regions where the phases of both modes nearly match.

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18

Goyal, R., R. P. Sharma i S. Kumar. "Nonlinear effects associated with quasi‐electrostatic whistler waves relevant to that in radiation belts". Journal of Geophysical Research: Space Physics 122, nr 1 (styczeń 2017): 340–48. http://dx.doi.org/10.1002/2016ja023274.

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Milić, B. S. "Excitation of long-wave quasi-perpendicular electrostatic ion-cyclotron waves in multi-species weakly ionized plasmas". Journal of Plasma Physics 43, nr 1 (luty 1990): 23–50. http://dx.doi.org/10.1017/s0022377800014604.

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It is shown, using kinetic equations with BGK model collision integrals, that in a multi-species weakly ionized plasma the quasi-perpendicular ion-cyclotron instability (waves of growing amplitude) excited by the electron drift parallel to the background magnetic field first sets in for long waves (modal wavelengths much larger than the electron mean free path) as the drift is gradually increased, much as in plasmas with only one ion species. Only waves with modal frequencies close to some cyclotron harmonics of some of the ion species present are taken into account in the present work. Owing to the mutual commensurability of all the ion-cyclotron frequencies, more than one species of ions may be ‘resonant’ with any mode of the type considered. The role of ‘resonant’ and ‘non-resonant’ ion species is investigated, both in general and for some particular plasmas. Some numerical details are also given. It is shown that although in most instances the threshold drifts vary monotonically (but not linearly) as the plasma composition is varied, there are cases in which maxima or minima (often depending on the degree of non-isothermality) of the threshold drift magnitude are predicted for some specific plasma compositions. These are usually encountered in plasmas containing ions with different charge numbers.

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20

Ha, Yuan K. "Weighing the black hole via quasi-local energy". Modern Physics Letters A 32, nr 24 (10.07.2017): 1730021. http://dx.doi.org/10.1142/s021773231730021x.

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We set to weigh the black holes at their event horizons in various spacetimes and obtain masses which are substantially higher than their asymptotic values. In each case, the horizon mass of a Schwarzschild, Reissner–Nordström, or Kerr black hole is found to be twice the irreducible mass observed at infinity. The irreducible mass does not contain electrostatic or rotational energy, leading to the inescapable conclusion that particles with electric charges and spins cannot exist inside a black hole. This is proposed as the External Energy Paradigm. A higher mass at the event horizon and its neighborhood is obligatory for the release of gravitational waves in binary black hole merging. We describe how these horizon mass values are obtained in the quasi-local energy approach and applied to the black holes of the first gravitational waves GW150914.

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21

Volosevich, A. V., i Y. I. Galperin. "Nonlinear wave structures in collisional plasma of auroral E-region ionosphere". Annales Geophysicae 15, nr 7 (31.07.1997): 890–98. http://dx.doi.org/10.1007/s00585-997-0890-8.

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Abstract. Studies of the auroral plasma with small-scale inhomogenieties producing the VHF-radar reflections (radar aurora) when observed in conditions of the saturated Farley-Buneman instability within the auroral E region, show strong nonlinear interactions and density fluctuations of 5–15%. Such nonlinearity and high fluctation amplitudes are inconsistent with the limitations of the weak turbulence theory, and thus a theory for arbitrary amplitudes is needed. To this end, a nonlinear theory is described for electrostatic MHD moving plasma structures of arbitrary amplitude for conditions throughout the altitude range of the collisional auroral E region. The equations are derived, from electron and ion motion self-consistent with the electric field, for the general case of the one-dimensional problem. They take into account nonlinearity, electron and ion inertia, diffusion, deviation from quasi-neutrality, and dynamical ion viscosity. The importance of the ion viscosity for dispersion is stressed, while deviation from the quasi-neutrality can be important only at rather low plasma densities, not typical for the auroral E region. In a small amplitude limit these equations have classical nonlinear solutions of the type of "electrostatic shock wave" or of knoidal waves. In a particular case these knoidal waves degrade to a dissipative soliton. A two-dimensional case of a quasi-neutral plasma is considered in the plane perpendicular to the magnetic field by way of the Poisson brackets, but neglecting the nonlinearity and ion inertia. It is shown that in these conditions an effective saturation can be achieved at the stationary turbulence level of order of 10%.

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Ohmi, Norichika, i Masashi Hayakawa. "On the generation of quasi-electrostatic half-electron-gyrofrequency VLF emissions in the magnetosphere". Journal of Plasma Physics 35, nr 3 (czerwiec 1986): 351–73. http://dx.doi.org/10.1017/s0022377800011405.

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A theoretical study is made of the generation mechanism of quasi-electrostatic VLF emissions observed in the distant magnetosphere, with frequency greater than half the electron gyrofrequency and with wave normal around the cold plasma oblique resonance cone. The two-component plasma is treated, composed of cold electrons and hot electrons with bi-Maxwellian and loss-cone distribution functions. The effects of various plasma parameters on the instability characteristics are examined in order to estimate their relative importance in determining the properties of unstable waves. It is found that both types of hot plasma distribution function can account for quasi-electrostatic half-gyrofrequency emissions. The frequency where the maximum growth rate occurs is mainly determined by the temperature anisotropy of the hot plasma, and the wave normal angle where maximum growth is expected is determined by the temperature of the hot plasma and the ratio of the cold to hot plasma densities. These theoretical considerations form the basis of a suggested plasma model which is able to explain our experimental direction-finding results.

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23

Zakharov, V. E., i C. V. Meister. "Transport of thermal plasma above the auroral ionosphere in the presence of electrostatic ion-cyclotron turbulence". Annales Geophysicae 17, nr 1 (31.01.1999): 27–36. http://dx.doi.org/10.1007/s00585-999-0027-3.

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Abstract. The electron component of intensive electric currents flowing along the geomagnetic field lines excites turbulence in the thermal magnetospheric plasma. The protons are then scattered by the excited electromagnetic waves, and as a result the plasma is stable. As the electron and ion temperatures of the background plasma are approximately equal each other, here electrostatic ion-cyclotron (EIC) turbulence is considered. In the nonisothermal plasma the ion-acoustic turbulence may occur additionally. The anomalous resistivity of the plasma causes large-scale differences of the electrostatic potential along the magnetic field lines. The presence of these differences provides heating and acceleration of the thermal and energetic auroral plasma. The investigation of the energy and momentum balance of the plasma and waves in the turbulent region is performed numerically, taking the magnetospheric convection and thermal conductivity of the plasma into account. As shown for the quasi-steady state, EIC turbulence may provide differences of the electric potential of ΔV≈1–10 kV at altitudes of 500 < h < 10 000 km above the Earth's surface. In the turbulent region, the temperatures of the electrons and protons increase only a few times in comparison with the background values.Key words. Magnetospheric physics (electric fields; plasma waves and instabilities)

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24

Rypdal, K. "Acceleration and heating in quasi-linear diffusion". Journal of Plasma Physics 35, nr 3 (czerwiec 1986): 413–29. http://dx.doi.org/10.1017/s0022377800011430.

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Quasi-linear diffusion of charged particles due to a stationary and homogeneous spectrum of electrostatic field fluctuations is investigated via a Fokker-Planck approach. The energy of a given distribution of test particles is found to be conserved whenever the wave spectrum is isotropic and none of the spectral components of the field has a phase speed that equals the speed of any test particle. Quite generally, the energy is monotonically increasing for isotropic spectra. An interesting quantum mechanical interpretation of these results is given, and the special case of beam evolution in an isotropic spectrum of non-dispersive waves is studied in some detail. Conditions for isotropization of directed electron and ion beams from Coulomb collisions and collective oscillations are discussed in the context of the quasi-linear description. Some promising results from a beam-plasma experiment are quoted.

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25

Simic, Darko, i Dragan Gajic. "Kinetic theory of electrostatic ion cyclotron waves (QPESIC) in multicomponent plasmas with negative ions". Facta universitatis - series: Physics, Chemistry and Technology 5, nr 1 (2007): 45–55. http://dx.doi.org/10.2298/fupct0701045s.

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The instabilities of the quasi-perpendicular electrostatic (?B = 0) ioncyclotron waves (QPESIC) are investigated. The kinetic theory with BGK model collision integrals is used to estimate the critical electron drift velocity in the presence of positively or negatively charged resonant ions in multi-component plasma. Analytical evaluation for the ion-cyclotron modes and instabilities in the long-wave range in a weakly-ionized Maxwellian plasma with two positive ion species, one negative ion species and with electrons, drifting along magnetic lines of force is demonstrated. The spectrum in these situations is also given. It is shown that the critical drift decreases as the state of plasma approaches the isothermic state.

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Pokhotelov, O. A., i O. A. Amariutei. "Quasi-linear dynamics of Weibel instability". Annales Geophysicae 29, nr 11 (4.11.2011): 1997–2001. http://dx.doi.org/10.5194/angeo-29-1997-2011.

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Abstract. The quasi-linear dynamics of resonant Weibel mode is discussed. It is found that nonlinear saturation of Weibel mode is accompanied by substantial modification of the distribution function in resonant region. With the growth of the wave amplitude the parabolic bell-like form of the electron distribution function in this region converts into flatter shape, such as parabola of the fourth order. This results in significant weakening of the resonant interaction of the wave with particles. The latter becomes weaker and then becomes adiabatic interaction with the bulk of the plasma. This is similar to the case of Bernstein-Greene-Kruskal (Bernstein et al., 1957) electrostatic waves. The mathematical similarity of the Weibel and magnetic mirror instabilities is discussed.

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Dusenbery, P. B., i L. R. Lyons. "Unmagnetized diffusion for azimuthally symmetric wave and particle distributions". Journal of Plasma Physics 40, nr 1 (sierpień 1988): 179–98. http://dx.doi.org/10.1017/s0022377800013192.

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The general equations describing the quasi-linear diffusion of charged particles from resonant interactions with a spectrum of electrostatic waves are given, assuming the wave and particle distributions to be azimuthally symmetric. These equations apply when a magnetic field organizes the wave and particle distributions in space, but when the local interaction between the waves and particles can be evaluated assuming that no magnetic field is present. Such diffusion is, in general, two-dimensional and is similar to magnetized diffusion. The connection between the two types of diffusion is presented. In order to apply the general quasi-linear diffusion coefficients in pitch angle and speed, a specific particle-distribution model is assumed. An expression for the unmagnetized dielectric function is derived and evaluated for the assumed particle distribution model. It is found that slow-mode ion-sound waves are unstable for the range of plasma parameters considered. A qualitative interpretation of unmagnetized diffusion is presented. The diffusion coefficients are then evaluated for resonant ion interactions with ion-sound waves. The results illustrate how resonant ion diffusion rates vary with pitch angle and speed, and how the diffusion rates depend upon the distribution of wave energy in k–space. The results of this study have relevance for ion beam heating in the plasma-sheet boundary layer and upstream of the earth's bow shock.

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Goel, D., P. Chauhan, A. Varshney i V. Sajal. "Parametric excitation of surface plasma waves by stimulated Compton scattering of laser beam at metal-free space interface". Laser and Particle Beams 34, nr 3 (27.06.2016): 467–73. http://dx.doi.org/10.1017/s0263034616000343.

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AbstractAn obliquely incident high-power laser (ω0,k0z) on the metallic surface can resonantly excite a surface plasma wave (SPW) (ω1,k1z) and a quasi-electrostatic plasma wave (ω,kz) inside the skin layer at the phase-matching conditions of frequency ω1= ω − ω0and wave numberk1z=kz−k0z. The oscillating electrons in the skin layer couples with the seed SPW and exert non-linear ponderomotive force on electrons at the frequency of quasi-static mode. Density perturbations due to quasi-static mode and ponderomotive force associate with the motion of electrons (due to incident laser) and give rise to a non-linear current by feedback mechanism. At ω/kz~vF(wherevFis the Fermi velocity of metal) this non-linear current is responsible for the growth of SPW. The maximum growth of the present process (≅1.5 × 1012s−1) is achieved at incident angle θ = 42° for laser frequency ω0= 2 × 1015rad/s. Growth of SPW enhances from 1.62 × 1011to ≅1.5 × 1012s−1as the magnetic field changes from 12 to 24 MG. The excited SPW can be utilized for surface heating and diagnostics purpose.

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Sugaya, R. "Momentum-space diffusion due to resonant wave–wave scattering of electromagnetic and electrostatic waves in a relativistic magnetized plasma". Journal of Plasma Physics 56, nr 2 (październik 1996): 193–207. http://dx.doi.org/10.1017/s0022377800019206.

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The momentum-space diffusion equation and the kinetic wave equation for resonant wave–wave scattering of electromagnetic and electrostatic waves in a relativistic magnetized plasma are derived from the relativistic Vlasov–Maxwell equations by perturbation theory. The p-dependent diffusion coefficient and the nonlinear wave—wave coupling coefficient are given in terms of third-order tensors which are amenable to analysis. The transport equations describing energy and momentum transfer between waves and particles are obtained by momentum-space integration of the momentum-space diffusion equation, and are expressed in terms of the nonlinear wave—wave coupling coefficient in the kinetic wave equation. The conservation laws for the total energy and momentum densities of waves and particles are verified from the kinetic wave equation and the transport equations. These equations are very useful for the theoretical analysis of transport phenomena or the acceleration and generation of high-energy or relativistic particles caused by quasi-linear and resonant wave—wave scattering processes.

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30

Bošková, Jaroslava, František Jiříček, Pavel Tříska, B. V. Lundin, D. R. Shklyar i M. Hvoždara. "On the problem of quasi-electrostatic whistler mode waves: A possible interpretation of discrete plasmaspheric emissions". Studia Geophysica et Geodaetica 32, nr 2 (czerwiec 1988): 199–212. http://dx.doi.org/10.1007/bf01637582.

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31

Muschietti, Laurent, i Bertrand Lembège. "Two-stream instabilities from the lower-hybrid frequency to the electron cyclotron frequency: application to the front of quasi-perpendicular shocks". Annales Geophysicae 35, nr 5 (15.09.2017): 1093–112. http://dx.doi.org/10.5194/angeo-35-1093-2017.

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Abstract. Quasi-perpendicular supercritical shocks are characterized by the presence of a magnetic foot due to the accumulation of a fraction of the incoming ions that is reflected by the shock front. There, three different plasma populations coexist (incoming ion core, reflected ion beam, electrons) and can excite various two-stream instabilities (TSIs) owing to their relative drifts. These instabilities represent local sources of turbulence with a wide frequency range extending from the lower hybrid to the electron cyclotron. Their linear features are analyzed by means of both a dispersion study and numerical PIC simulations. Three main types of TSI and correspondingly excited waves are identified: i. Oblique whistlers due to the (so-called fast) relative drift between reflected ions/electrons; the waves propagate toward upstream away from the shock front at a strongly oblique angle (θ ∼ 50°) to the ambient magnetic field Bo, have frequencies a few times the lower hybrid, and have wavelengths a fraction of the ion inertia length c∕ωpi. ii. Quasi-perpendicular whistlers due to the (so-called slow) relative drift between incoming ions/electrons; the waves propagate toward the shock ramp at an angle θ a few degrees off 90°, have frequencies around the lower hybrid, and have wavelengths several times the electron inertia length c∕ωpe. iii. Extended Bernstein waves which also propagate in the quasi-perpendicular domain, yet are due to the (so-called fast) relative drift between reflected ions/electrons; the instability is an extension of the electron cyclotron drift instability (normally strictly perpendicular and electrostatic) and produces waves with a magnetic component which have frequencies close to the electron cyclotron as well as wavelengths close to the electron gyroradius and which propagate toward upstream. Present results are compared with previous works in order to stress some features not previously analyzed and to define a more synthetic view of these TSIs.

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Hasan, M., i DMS Zaman. "Linear Nuclear Acoustic Waves in Degenerate Quantum Plasma". GUB Journal of Science and Engineering 5, nr 1 (28.06.2018): 20–23. http://dx.doi.org/10.3329/gubjse.v5i1.47896.

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A rigorous theoretical investigation has been made on the linear propagation of electrostatic perturbation modes of degenerate pressure driven modified nucleus-acoustic (DPDMNA) ‘waves in a degenerate quantum plasma (DQP) system. It contains cold inertia-less degenerate electron species (DES), cold inertial non-degenerate light nucleus species (LNS) and stationary heavy nucleus species (HNS) which maintains the quasi-neutrality condition at equilibrium only. The mass density of the cold LNS provides the inertia and the cold inertia-less cold LNS provides the inertia and the cold inertia-less DES gives rise to the restoring force. The reductive perturbation method has been used for the study of nonlinear propagation of the DPDMNA waves. The basic features of linear waves are supervised in a theoretical manner. It has been observed that the phase speed of DPDMNA waves changes with the change of charge density of the stationary HNS for both non-relativistic and ultra-relativistic DES; The NA waves with their dispersion properties which are consequential in various astrophysical and laboratory plasmas, have been broadly considered. GUB JOURNAL OF SCIENCE AND ENGINEERING, Vol 5(1), Dec 2018 P 20-23

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33

Shin, Koichi, Hirotsugu Kojima, Hiroshi Matsumoto i Toshifumi Mukai. "Electrostatic quasi-monochromatic waves in the downstream region of the Earth’s bow shock based on Geotail observations". Earth, Planets and Space 59, nr 2 (luty 2007): 107–12. http://dx.doi.org/10.1186/bf03352683.

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Yasin, E., A. AlKhateeb, F. Rawwagah i A. Abuzir. "On the coupling of forward and backward slow waves supported by the waveguide configuration of a dielectric sandwiched between two plasma slabs". Advanced Electromagnetics 9, nr 1 (1.05.2020): 95–99. http://dx.doi.org/10.7716/aem.v9i1.1368.

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We derived a general equation governing the spectra of electrostatic surface plasmons supported by a waveguide structure of two identical plasma slabs separated by a dielectric medium. The plasma slabs are parallel, homogeneous, and have finite thicknesses. The geometry under consideration supports two surface plasmon modes, which we investigated numerically for Polyethylene $\varepsilon_d=2.25$ and vacuum $\varepsilon_d=1$ as central regions. With vacuum as a central region, the two surface plasmon modes become coupled and merge into the well known single mode of quasi-static frequency $\omega=0.707\omega_{\rm p}$. The surface plasmon modes in the presence of a Polyethylene are decoupled and remain nondegenerate over the whole range of $kd$. Therefore, the two plasmon modes propagate independent of each other with distinct quasi-static resonance frequencies, namely, a backward wave with $\omega=0.707\omega_{\rm p}$ corresponding to a single plasma-vacuum interface and a forward wave with $\omega=\frac{\omega_{\rm p}}{\sqrt{3.25}}=0.55\omega_{\rm p}$ corresponding to a single plasma-dielectric interface. Increasing the central region width is found to introduce a delay in reaching the quasi-static resonance frequencies. The effect of collision is to down shift the mode frequencies for long wavelengths and also to down shift the quasi-static frequencies.

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Larosa, A., T. Dudok de Wit, V. Krasnoselskikh, S. D. Bale, O. Agapitov, J. Bonnell, C. Froment i in. "Langmuir-Slow Extraordinary Mode Magnetic Signature Observations with Parker Solar Probe". Astrophysical Journal 927, nr 1 (1.03.2022): 95. http://dx.doi.org/10.3847/1538-4357/ac4e85.

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Abstract Radio emission from interplanetary shocks, planetary foreshocks, and some solar flares occurs in the so-called “plasma emission” framework. The generally accepted scenario begins with electrostatic Langmuir waves that are driven by a suprathermal electron beam on the Landau resonance. These Langmuir waves then mode-convert to freely propagating electromagnetic emissions at the local plasma frequency f pe and/or its harmonic 2f pe . However, the details of the physics of mode conversion are unclear, and so far the magnetic component of the plasma waves has not been definitively measured. Several spacecraft have measured quasi-monochromatic Langmuir or slow extraordinary modes (sometimes called z-modes) in the solar wind. These coherent waves are expected to have a weak magnetic component, which has never been observed in an unambiguous way. Here we report on the direct measurement of the magnetic signature of these waves using the Search Coil Magnetometer sensor of the Parker Solar Probe/FIELDS instrument. Using simulations of wave propagation in an inhomogeneous plasma, we show that the appearance of the magnetic component of the slow extraordinary mode is highly influenced by the presence of density inhomogeneities that occasionally cause the refractive index to drop to low values where the wave has strong electromagnetic properties.

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Cattell, C., B. Short, A. Breneman, J. Halekas, P. Whittesley, D. Larson, J. C. Kasper i in. "Narrowband oblique whistler-mode waves: comparing properties observed by Parker Solar Probe at <0.3 AU and STEREO at 1 AU". Astronomy & Astrophysics 650 (czerwiec 2021): A8. http://dx.doi.org/10.1051/0004-6361/202039550.

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Aims. Large amplitude narrowband obliquely propagating whistler-mode waves at frequencies of ~0.2 fce (electron cyclotron frequency) are commonly observed at 1 AU, and they are most consistent with the whistler heat flux fan instability. We want to determine whether similar whistler-mode waves occur inside 0.3 AU and how their properties compare to those at 1 AU. Methods. We utilized the waveform capture data from the Parker Solar Probe Fields instrument from Encounters 1 through 4 to develop a data base of narrowband whistler waves. The Solar Wind Electrons Alphas and Protons Investigation (SWEAP) instrument, in conjunction with the quasi-thermal noise measurement from Fields, provides the electron heat flux, beta, and other electron parameters. Results. Parker Solar Probe observations inside ~0.3 AU show that the waves are often more intermittent than at 1 AU, and they are interspersed with electrostatic whistler-Bernstein waves at higher-frequencies. This is likely due to the more variable solar wind observed closer to the Sun. The whistlers usually occur within regions when the magnetic field is more variable and often with small increases in the solar wind speed. The near-Sun whistler-mode waves are also narrowband and large amplitude, and they are associated with beta greater than 1. The association with heat flux and beta is generally consistent with the whistler fan instability. Strong scattering of strahl energy electrons is seen in association with the waves, providing evidence that the waves regulate the electron heat flux.

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Karlsson, Tomas, Ferdinand Plaschke, Heli Hietala, Martin Archer, Xóchitl Blanco-Cano, Primož Kajdič, Per-Arne Lindqvist, Göran Marklund i Daniel J. Gershman. "Investigating the anatomy of magnetosheath jets – MMS observations". Annales Geophysicae 36, nr 2 (23.04.2018): 655–77. http://dx.doi.org/10.5194/angeo-36-655-2018.

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Abstract. We use Magnetosphere Multiscale (MMS) mission data to investigate a small number of magnetosheath jets, which are localized and transient increases in dynamic pressure, typically due to a combined increase in plasma velocity and density. For two approximately hour-long intervals in November, 2015 we found six jets, which are of two distinct types. (a) Two of the jets are associated with the magnetic field discontinuities at the boundary between the quasi-parallel and quasi-perpendicular magnetosheath. Straddling the boundary, the leading part of these jets contains an ion population similar to the quasi-parallel magnetosheath, while the trailing part contains ion populations similar to the quasi-perpendicular magnetosheath. Both populations are, however, cooler than the surrounding ion populations. These two jets also have clear increases in plasma density and magnetic field strength, correlated with a velocity increase. (b) Three of the jets are found embedded within the quasi-parallel magnetosheath. They contain ion populations similar to the surrounding quasi-parallel magnetosheath, but with a lower temperature. Out of these three jets, two have a simple structure. For these two jets, the increases in density and magnetic field strength are correlated with the dynamic pressure increases. The other jet has a more complicated structure, and no clear correlations between density, magnetic field strength and dynamic pressure. This jet has likely interacted with the magnetosphere, and contains ions similar to the jets inside the quasi-parallel magnetosheath, but shows signs of adiabatic heating. All jets are associated with emissions of whistler, lower hybrid, and broadband electrostatic waves, as well as approximately 10 s period electromagnetic waves with a compressional component. The latter have a Poynting flux of up to 40 µW m−2 and may be energetically important for the evolution of the jets, depending on the wave excitation mechanism. Only one of the jets is likely to have modified the surrounding magnetic field into a stretched configuration, as has recently been reported in other studies. None of the jets are associated with clear signatures of either magnetic or thermal pressure gradient forces acting on them. The different properties of the two types also point to different generation mechanisms, which are discussed here. Their different properties and origins suggest that the two types of jets need to be separated in future statistical and simulation studies. Keywords. Magnetospheric physics (magnetosheath; plasma waves and instabilities; solar wind–magnetosphere interactions)

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38

Donnelly, I. J., B. E. Clancy i N. F. Cramer. "Alfvén wave heating of a cylindrical plasma using axisymmetric waves. Part 2. Kinetic theory". Journal of Plasma Physics 35, nr 1 (luty 1986): 75–106. http://dx.doi.org/10.1017/s0022377800011144.

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Kinetic theory, including ion Larmor radius effects, is used to analyse the Alfvén wave heating of cylindrical plasmas using axisymmetric waves excited by an antenna at frequencies up to the ion cyclotron frequency. At the Alfvén resonance position, the compressional wave is mode converted to a quasi-electrostatic wave (QEW) which propagates towards the plasma centre or edge depending on whether the plasma is hot or warm. The energy absorbed by the plasma agrees with the MHD theory predictions provided the QEW is heavily damped before reaching the plasma centre or edge; if it is not, then QEW resonances may occur with a consequent increase in antenna resistance. The relation between ion cyclotron wave resonances and QEW resonances in a hot plasma is shown. The behaviour described above is demonstrated by numerical solution of the wave equations for small and large tokamak-like plasmas. WKB theory has been used to derive useful expressions which quantify the QEW behaviour.

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Muñoz, Andrés G., i Stephan Weiss. "Kinetic Aspects of the Electrochemical Reduction of Uranyl in HCl Solutions". Journal of The Electrochemical Society 169, nr 1 (1.01.2022): 016510. http://dx.doi.org/10.1149/1945-7111/ac3e7c.

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The interfacial mechanism of uranyl electroreduction at Au-electrodes in HCl solutions was discussed on the light of systematic studies of cyclovoltammetry, normal pulse voltammetry, UV–vis spectroscopy and published electroanalytical research. Voltammetric waves were numerically deconvoluted on the basis of a reaction model consisting of a first mass-controlled, quasi-reversible first electron transfer and a subsequent reduction of interfacial U(V) intermediate species with adsorption of generated U(IV) products. The dependence of the kinetic parameters on [HCl] indicates an electron transfer following an inner-sphere type mechanism assisted by electrosorption of chloride ligands. The interfacial accumulation of chloride exerts a strong electrostatic repulsion of complexed uranyl and a consequent edged drop of electron transfer rates at [HCl] ∼ 0.5 mol l−1. The electron transfer steps are followed by a chemical desorption reaction of the unstable tetravalent uranyl in U(H2O)9 4+ species. It is shown that the numerical reproduction of voltammetric waves suits as a method for calculating kinetic parameters in multi-steps electrochemical reactions.

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40

Galeev, A. A., M. A. Malkov i H. J. Völk. "Macroscopic electric fields driven by lower-hybrid turbulence and acceleration of thermal electrons in the foot of quasi-perpendicular shocks". Journal of Plasma Physics 54, nr 1 (sierpień 1995): 59–76. http://dx.doi.org/10.1017/s0022377800018341.

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A new mechanism is suggested that draws non-resonant thermal electrons into a higher-velocity range, where they can be effectively accelerated by waves. We argue that the acceleration of a small number of pre-existing resonant particles influences the dynamics of the bulk plasma and results in a macroscopic electric field. The solution for the spatial dependence of this electric field is obtained, and it appears to be a new type of electrostatic shock, which forms only in the presence of background turbulence. This field enriches the region of resonant particles with thermal electrons, which leads to a build-up of an excess of accelerated particles. The number of accelerated particles is calculated. This mechanism appears as a good candidate to explain electron acceleration in the foot of quasi-perpendicular shocks.

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Borisov, N. "Interaction of the high frequency waves in the vicinity of the ionospheric window". Physics of Plasmas 30, nr 3 (marzec 2023): 032110. http://dx.doi.org/10.1063/5.0132196.

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It is well-known that an ordinary high frequency electromagnetic (EM) wave radiated into the ionosphere at the Spitze angle is totally transformed at the reflection height ( z0) into the Z-mode. This mode, in turn, penetrates deeper into the ionosphere and it is reflected at some height ( zref) usually significantly higher than the O-mode reflection height. This result is reconsidered in the present paper. It is argued that the wave appearing as a continuation of the propagating upward quasi-electrostatic wave changes the direction of motion along the vertical axis slightly above z0 and takes the form of the down-going wave. This wave is excited in the vicinity of the height z0 due to the phase resonance with the up-going O-mode wave which transforms into the Z-mode propagating upward. Thus, the ionospheric window is not totally transparent for the O-mode radiated at the Spitze angle. The up-going O-mode wave loses some part of its energy due to excitation of the down-going EM wave. This wave, in turn, propagates to the ground as the O-mode wave.

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Foust, F. R., U. S. Inan, T. Bell i N. G. Lehtinen. "Quasi-electrostatic whistler mode wave excitation by linear scattering of EM whistler mode waves from magnetic field-aligned density irregularities". Journal of Geophysical Research: Space Physics 115, A11 (listopad 2010): n/a. http://dx.doi.org/10.1029/2010ja015850.

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Kakad, Bharati, Amar Kakad, Harikrishnan Aravindakshan i Ioannis Kourakis. "Debye-scale Solitary Structures in the Martian Magnetosheath". Astrophysical Journal 934, nr 2 (1.08.2022): 126. http://dx.doi.org/10.3847/1538-4357/ac7b8b.

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Abstract We present an analysis of 450 solitary wave pulses observed by the Langmuir Probe and Waves instrument on the Mars Atmosphere and Volatile EvolutioN spacecraft during its five passes around Mars on 2015 February 9. The magnitude and duration of these pulses vary between 1 and 25 mV m−1 and 0.2–1.7 ms, respectively. The ambient plasma conditions suggest that these pulses are quasi-parallel to the ambient magnetic field and can be considered electrostatic. These pulses are dominantly seen in the dawn (5–6 LT) and afternoon-dusk (15–18 LT) sectors at an altitude of 1000–3500 km. The frequencies of these electric field pulses are close to the ion plasma frequency (i.e., f pi ≤ f ef ≪ f pe), which suggests that their formation is governed by ion dynamics. The computer simulation performed for the Martian magnetosheath plasma hints that these pulses are ion-acoustic solitary waves generated by drifted ion and electron populations and their spatial scales are in the range of few ion Debye lengths (1.65–10λ di). This is the first study to report and model solitary wave structures in the Martian magnetosheath.

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Su, Yi-Jiun. "Electromagnetic interaction between Jupiter's ionosphere and the Io plasma torus". Proceedings of the International Astronomical Union 4, S259 (listopad 2008): 271–82. http://dx.doi.org/10.1017/s1743921309030610.

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AbstractThe electromagnetic interaction between Jupiter and Io has been studied extensively since the discovery of Io-controlled decametric radio emissions (DAMs). A variety of mechanisms for electromagnetic disturbances have been considered including a unipolar inductor, the excitation of large-amplitude Alfvén waves, the generation of electrostatic electric fields parallel to the ambient magnetic field, and etc. Recently, three auroral acceleration regions categorized by terrestrial physicists have been applied to the Jupiter-Io coupling system: the Alfvénic acceleration region is associated with bright emissions at Io's magnetic footprint, whereas the quasi-static system of anti-planetward and planetward currents set up at the inner and outer edges of the torus in the downstream region of Io's wake. This review paper summarizes the current understanding of the coupling mechanisms between Jupiter's ionosphere and the Io plasma torus, as well as the electron acceleration mechanism necessary to excite Io-associated emissions.

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Shirokov, E. A., A. G. Demekhov, Yu V. Chugunov i A. V. Larchenko. "Effective length of a receiving antenna in case of quasi-electrostatic whistler mode waves: Application to spacecraft observations of chorus emissions". Radio Science 52, nr 7 (lipiec 2017): 884–95. http://dx.doi.org/10.1002/2016rs006235.

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Yu, Chunkai, Zhongwei Yang, Xinliang Gao, Quanming Lu i Jian Zheng. "Electron Acceleration by Moderate-Mach-number Low-β Shocks: Particle-in-Cell Simulations". Astrophysical Journal 930, nr 2 (1.05.2022): 155. http://dx.doi.org/10.3847/1538-4357/ac67df.

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Abstract Particle acceleration is ubiquitous at shock waves, occurring on scales ranging from supernova remnants in the universe to coronal-mass-ejection-driven shocks and planetary bow shocks in the heliosphere. The most promising mechanism responsible for the almost universally observed power-law spectra is diffusive shock acceleration (DSA). However, how electrons are preaccelerated by different shocks to the energy required by the DSA theory is still unclear. In this paper, we perform two-dimensional particle-in-cell plasma simulations to investigate how the magnetic field orientations, with respect to simulation planes, affect electron preacceleration in moderate-Mach-number low- β shocks. Simulation results show that instabilities can be different as the simulation planes capture different trajectories of particles. For magnetic fields perpendicular to the simulation plane, electron cyclotron drift instability dominates in the foot. Electrons can be trapped by the electrostatic wave and undergo shock-surfing acceleration. For magnetic fields lying in the simulation plane, whistler waves produced by modified two-stream instability dominate in the foot and scatter the electrons. In both cases, electrons undergo multistage acceleration in the foot, shock surface, and immediate downstream, during which process shock-surfing acceleration takes place as part of the preacceleration mechanism in moderate-Mach-number quasi-perpendicular shocks.

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Narita, Y., H. Comişel i U. Motschmann. "Critical pitch angle for electron acceleration in a collisionless shock layer". Annales Geophysicae 34, nr 7 (12.07.2016): 591–93. http://dx.doi.org/10.5194/angeo-34-591-2016.

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Abstract. Collisionless shock waves in space and astrophysical plasmas can accelerate electrons along the shock layer by an electrostatic potential, and scatter or reflect electrons back to the upstream region by the amplified magnetic field or turbulent fluctuations. The notion of the critical pitch angle is introduced for non-adiabatic electron acceleration by balancing the two timescales under a quasi-perpendicular shock wave geometry in which the upstream magnetic field is nearly perpendicular to the shock layer normal direction. An analytic expression of the critical pitch angle is obtained as a function of the electron velocity parallel to the magnetic field, the ratio of the electron gyro- to plasma frequency, the cross-shock potential, the width of the shock transition layer, and the shock angle (which is the angle between the upstream magnetic field and the shock normal direction). For typical non-relativistic solar system applications, the critical pitch angle is predicted to be about 10°. An efficient acceleration is expected below the critical pitch angle.

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Hysell, D. L., M. F. Larsen i Q. H. Zhou. "Common volume coherent and incoherent scatter radar observations of mid-latitude sporadic E-layers and QP echoes". Annales Geophysicae 22, nr 9 (23.09.2004): 3277–90. http://dx.doi.org/10.5194/angeo-22-3277-2004.

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Abstract. Common-volume observations of sporadic E-layers made on 14-15 June 2002 with the Arecibo incoherent scatter radar and a 30MHz coherent scatter radar imager located on St. Croix are described. Operating in dual-beam mode, the Arecibo radar detected a slowly descending sporadic E-layer accompanied by a series of dense E-region plasma clouds at a time when the coherent scatter radar was detecting quasi-periodic (QP) echoes. Using coherent radar imaging, we collocate the sources of the coherent scatter with the plasma clouds observed by Arecibo. In addition to patchy, polarized scattering regions drifting through the radar illuminated volume, which have been observed in previous imaging experiments, the 30MHz radar also detected large-scale electrostatic waves in the E-region over Puerto Rico, with a wavelength of about 30km and a period of about 10min, propagating to the southwest. Both the intensity and the Doppler shifts of the coherent echoes were modulated by the wave.

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Shirokov, E. A. "Self-Consistent Stationary Distributions of the Electric Field and Plasma Density in the Process of Ionization Self-Channeling of Quasi-Electrostatic Waves". Izvestiya vysshikh uchebnykh zavedenii. Radiofizika 63, nr 12 (2020): 1022–31. http://dx.doi.org/10.52452/00213462_2020_63_12_1022.

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Shmuel, Gal, i Gal deBotton. "Axisymmetric wave propagation in finitely deformed dielectric elastomer tubes". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 469, nr 2155 (8.07.2013): 20130071. http://dx.doi.org/10.1098/rspa.2013.0071.

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Wave propagation in hollow dielectric elastomer cylinders is studied. The quasi-static deformation of the tube owing to a combination of radial electric field and mechanical loading is determined first. Two combinations are accounted for, one at which the tube is free to expand in the axial direction, and another at which the tube is axially pre-stretched and restricted from elongating. Subsequently, longitudinal axisymmetric incremental motions are superposed on the underlying state. The governing equations in the tube and in the surrounding space are formulated and a numerical procedure is used in order to solve the resulting set of equations. The fundamental mode in the frequency spectrum is determined for thin, intermediate and thick wall tubes. The influences of the tube geometry, the mechanical pre-stretch and particularly the electric bias field are examined. An important observation is the ability to manipulate the propagation of the waves by adjusting the electromechanical bias field. This infers the use of dielectric elastomers in tubular configurations as active waveguides or isolators by a proper tuning of the electrostatic stimuli.

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