Articles de revues : « Electron Cyclotron Waves »

1

Hoekzema, J. A. « Electron Cyclotron Waves ». Fusion Science and Technology 45, n^o 2T (mars 2004) : 211–16. http://dx.doi.org/10.13182/fst04-a485.

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Westerhof, Egbert. « Electron Cyclotron Waves ». Fusion Science and Technology 49, n^o 2T (février 2006) : 195–201. http://dx.doi.org/10.13182/fst06-a1119.

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Egbert, Westerhof. « Electron Cyclotron Waves ». Fusion Science and Technology 53, n^o 2T (février 2008) : 202–9. http://dx.doi.org/10.13182/fst08-a1706.

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Westerhof, Egbert. « Electron Cyclotron Waves ». Fusion Science and Technology 57, n^o 2T (février 2010) : 214–21. http://dx.doi.org/10.13182/fst10-a9412.

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Westerhof, Egbert. « Electron Cyclotron Waves ». Fusion Science and Technology 61, n^o 2T (février 2012) : 304–11. http://dx.doi.org/10.13182/fst12-a13517.

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Tsurutani, B. T., B. Dasgupta, J. K. Arballo, G. S. Lakhina et J. S. Pickett. « Magnetic field turbulence, electron heating, magnetic holes, proton cyclotron waves, and the onsets of bipolar pulse (electron hole) events : a possible unifying scenario ». Nonlinear Processes in Geophysics 10, n^o 1/2 (30 avril 2003) : 27–35. http://dx.doi.org/10.5194/npg-10-27-2003.

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Abstract. Two electron heating events have been identified on 20 May 1996 when Polar was in the polar cap/polar cusp boundary layer. The electron heating events were located within magnetic holes/cavities/bubbles and were accompanied by nonlinear ± 14 nT peak-to-peak (f ~ 0.6 to 0.7 fcp) obliquely propagating proton cyclotron waves. The electrons appear to be heated isotropically. Electric bipolar pulse (electron hole) onset events were also detected within the heating events. We propose a scenario which can link the above phenomena. Nonlinear Alfvén waves, generated through cusp magnetic reconnection, propagate down magnetic field lines and locally heat electrons through the ponderomotive force. The magnetic cavity is created through the diamagnetic effect of the heated electrons. Ion heating also occurs through ponderomotive acceleration (but much less than the electrons) and the protons generate the electromagnetic proton cyclotron waves through the loss cone instability. The obliquely propagating electromagnetic proton cyclotron waves accelerate bi-streaming electrons, which are the source of free energy for the electron holes.

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Bharuthram, R., S. V. Singh, S. K. Maharaj, S. Moolla, I. J. Lazarus, R. V. Reddy et G. S. Lakhina. « Do nonlinear waves evolve in a universal manner in dusty and other plasma environments ? » Journal of Plasma Physics 80, n^o 6 (14 juillet 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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Ram, Abhay K., Kyriakos Hizanidis et Richard J. Temkin. « Current drive by high intensity, pulsed, electron cyclotron wave packets ». EPJ Web of Conferences 203 (2019) : 01009. http://dx.doi.org/10.1051/epjconf/201920301009.

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The nonlinear interaction of electrons with a high intensity, spatially localized, Gaussian, electro-magnetic wave packet, or beam, in the electron cyclotron range of frequencies is described by the relativistic Lorentz equation. There are two distinct sets of electrons that result from wave-particle interactions. One set of electrons is reﬂected by the ponderomotive force due to the spatial variation of the wave packet. The second set of electrons are energetic enough to traverse across the wave packet. Both sets of electrons can exchange energy and momentum with the wave packet. The trapping of electrons in plane waves, which are constituents of the Gaussian beam, leads to dynamics that is distinctly diﬀerent from quasilinear modeling of wave-particle interactions. This paper illustrates the changes that occur in the electron motion as a result of the nonlinear interaction. The dynamical diﬀerences between electrons interacting with a wave packet composed of ordinary electromagnetic waves and electrons interacting with a wave packet composed of extraordinary waves are exempliﬁed.

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Novak, O., R. Kholodov et A. Fomina. « Role of Double Layers in the Formation of Conditions for a Polarization Phase Transition to the Superradiancestate in the Io Flux Tube ». Ukrainian Journal of Physics 63, n^o 8 (7 septembre 2018) : 740. http://dx.doi.org/10.15407/ujpe63.8.740.

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A possibility of the electron phase transition into cyclotron superradiance mode in a vicinity of the Io flux tube foot in the Jovian magnetosphere has been considered. A high power of cyclotron superradiance allows it to be considered as the main mechanism of decameter Jupiter radiation generation in the form of S-bursts. It was found that the downward electron beams emitted by Io are able to create electric double layers in the form of shock waves. Such waves, when moving along the flux tube, accelerate electrons in the magnetosphere. As a result, the temperature of the electron plasma component decreases considerably. The emerging upward electron beams create conditions favorable for the phase transition into the cyclotron superradiance mode to take place.

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Shukla, P. K., M. Y. Yu et L. Stenflo. « Modulational instabilities of electron cyclotron waves ». Physical Review A 34, n^o 2 (1 août 1986) : 1582–83. http://dx.doi.org/10.1103/physreva.34.1582.

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Alikaev, V. V., et V. V. Parail. « Current drive by electron cyclotron waves ». Plasma Physics and Controlled Fusion 33, n^o 13 (1 novembre 1991) : 1639–56. http://dx.doi.org/10.1088/0741-3335/33/13/011.

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12

Yang, Kwang-Sup. « Relativistic transverse modulational instability of two electron cyclotron waves ». Journal of Plasma Physics 55, n^o 3 (juin 1996) : 327–38. http://dx.doi.org/10.1017/s0022377800018882.

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The transverse modulational instabilities of two finite-amplitude electron-cyclotron waves due to the ponderomotive force and relativistic mass variation of electrons are considered using the coupled nonlinear Schrödinger equation model. The waves are modulationally unstable, with maximum growth rate larger than that of a single wave. The stable waves can be unstable by the effect of coupling. The instability is caused only by the mass variation of electrons, and the contribution of the ponderomotive force is negligibly small. The instability of copropagating waves has a convective nature and that due to the counterpropagating waves has an absolute nature, no matter how large the pump intensities are. The threshold of modulational instability is also considered for finite-length plasmas.

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13

Zhou, Xiaowei, Dejin Wu et Ling Chen. « Plasma Emission versus Electron Cyclotron Maser Emission due to Power-law Energetic Electrons in Differently Magnetized Coronal Plasmas ». Astrophysical Journal 928, n^o 2 (31 mars 2022) : 115. http://dx.doi.org/10.3847/1538-4357/ac5aae.

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Abstract By using self-consistent 2.5-dimensional particle-in-cell simulations, we study the excitation efficiency of electromagnetic waves by power-law energetic electrons with an anisotropic pitch-angle velocity distribution, which can simultaneously trigger the Langmuir and electron cyclotron maser instabilities, in differently magnetized coronal plasmas. It is found that the (transverse) electromagnetic waves can be excited much more efficiently in the case of strongly magnetized plasmas with ω ce > ω pe than that of weakly magnetized plasmas with ω ce < ω pe, where ω ce and ω pe are the electron cyclotron frequency and the electron plasma frequency, respectively. In particular, in a weakly magnetized plasma the electromagnetic wave is hardly excited effectively via the nonlinear coupling of Langmuir waves; although the Langmuir waves can be generated by the power-law energetic electrons, implying that the so-called plasma emission does not effectively work. These results can be helpful for us to better understand the physical mechanism of solar radio bursts.

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Woodfield, E. E., R. B. Horne, S. A. Glauert, J. D. Menietti et Y. Y. Shprits. « Electron acceleration at Jupiter : input from cyclotron-resonant interaction with whistler-mode chorus waves ». Annales Geophysicae 31, n^o 10 (2 octobre 2013) : 1619–30. http://dx.doi.org/10.5194/angeo-31-1619-2013.

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Abstract. Jupiter has the most intense radiation belts of all the outer planets. It is not yet known how electrons can be accelerated to energies of 10 MeV or more. It has been suggested that cyclotron-resonant wave-particle interactions by chorus waves could accelerate electrons to a few MeV near the orbit of Io. Here we use the chorus wave intensities observed by the Galileo spacecraft to calculate the changes in electron flux as a result of pitch angle and energy diffusion. We show that, when the bandwidth of the waves and its variation with L are taken into account, pitch angle and energy diffusion due to chorus waves is a factor of 8 larger at L-shells greater than 10 than previously shown. We have used the latitudinal wave intensity profile from Galileo data to model the time evolution of the electron flux using the British Antarctic Survey Radiation Belt (BAS) model. This profile confines intense chorus waves near the magnetic equator with a peak intensity at ∼5° latitude. Electron fluxes in the BAS model increase by an order of magnitude for energies around 3 MeV. Extending our results to L = 14 shows that cyclotron-resonant interactions with chorus waves are equally important for electron acceleration beyond L = 10. These results suggest that there is significant electron acceleration by cyclotron-resonant interactions at Jupiter contributing to the creation of Jupiter's radiation belts and also increasing the range of L-shells over which this mechanism should be considered.

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15

WILLES, A. J., et P. A. ROBINSON. « Electron-cyclotron maser theory for extraordinary Bernstein waves ». Journal of Plasma Physics 58, n^o 1 (juillet 1997) : 171–91. http://dx.doi.org/10.1017/s0022377897005874.

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Electron-cyclotron maser emission is investigated in the regime where wave growth in the electrostatic Bernstein modes dominates (ωp/Ωe>1.5). A semirelativistic growth rate is derived assuming that the wave dispersion is dominated by a cool background electron distribution and the instability is driven by a low-density hot loss-cone-like electron distribution. The properties of Bernstein wave growth are most strongly dependent on the relative temperatures of the hot and cool electron distributions. For Thot/Tcool[gsim ]10, the fastest growing Bernstein waves are produced at frequencies just below each cyclotron harmonic in Bernstein modes lying below the upper-hybrid frequency. For Thot/Tcool[lsim ]10, additional Bernstein modes above the upper-hybrid frequency are excited, with wave frequencies in each excited mode lying significantly above the corresponding cyclotron harmonic. The dependence of Bernstein wave growth on the relative hot and cool electron number densities and emission angle is also discussed.

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Tonoian, D. S., A. V. Artemyev, X. J. Zhang, M. M. Shevelev et D. L. Vainchtein. « Resonance broadening effect for relativistic electron interaction with electromagnetic ion cyclotron waves ». Physics of Plasmas 29, n^o 8 (août 2022) : 082903. http://dx.doi.org/10.1063/5.0101792.

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Relativistic electron scattering by electromagnetic ion cyclotron (EMIC) waves is one of the most effective mechanisms for >1 MeV electron flux depletion in the Earth's radiation belts. Resonant electron interaction with EMIC waves is traditionally described by quasi-linear diffusion equations, although spacecraft observations often report EMIC waves with intensities sufficiently large to trigger nonlinear resonant interaction with electrons. An important consequence of such nonlinear interaction is the resonance broadening effect due to high wave amplitudes. In this study, we quantify this resonance broadening effect in electron pitch-angle diffusion rates. We show that resonance broadening can significantly increase the pitch-angle range of EMIC-scattered electrons. This increase is especially important for [Formula: see text] MeV electrons, where, without the resonance broadening, only those near the loss cone (with low fluxes) can resonate with EMIC waves.

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17

Muschietti, Laurent, et 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, n^o 5 (15 septembre 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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Narita, Y., E. Marsch, C. Perschke, K. H. Glassmeier, U. Motschmann et H. Comişel. « Wave–particle resonance condition test for ion-kinetic waves in the solar wind ». Annales Geophysicae 34, n^o 4 (7 avril 2016) : 393–98. http://dx.doi.org/10.5194/angeo-34-393-2016.

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Abstract. Conditions for the Landau and cyclotron resonances are tested for 543 waves (identified as local peaks in the energy spectra) in the magnetic field fluctuations of the solar wind measured by the Cluster spacecraft on a tetrahedral scale of 100 km. The resonance parameters are evaluated using the frequencies in the plasma rest frame, the parallel components of the wavevectors, the ion cyclotron frequency, and the ion thermal speed. The observed waves show a character of the sideband waves associated with the ion Bernstein mode, and are in a weak agreement with the fundamental electron cyclotron resonance in spite of the ion-kinetic scales. The electron cyclotron resonance is likely taking place in solar wind turbulence near 1 AU (astronomical unit).

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Алексеев, П. С. « Магнитозвуковые волны в двумерной электронной ферми-жидкости ». Физика и техника полупроводников 53, n^o 10 (2019) : 1405. http://dx.doi.org/10.21883/ftp.2019.10.48298.9166.

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The properties of highly viscous fluids at high frequencies become similar to the properties of amorphous solids. In particular, it becomes possible to propagate not only longitudinal sound waves (plasmons for the case of an electron fluid), but also transverse sound waves associated with shear deformations. In this work, transverse sound waves at high frequencies in a twodimensional electron liquid in a magnetic field are studied. The consideration was carried out in the framework of the Landau Fermi-liquid model. It is shown that for a sufficiently large interaction between quasiparticles, the dynamics of excitations of a Fermi liquid is described by the equations of hydrodynamics. The Navier-Stokes equation and expressions for high-frequency shear viscosity coefficients are derived. Based on the equations obtained, the dispersion laws are calculated for transverse and longitudinal magnetosonic waves. It is shown that the cyclotron frequency, which enters in the viscosity coefficients and the dispersion law of transverse magnetosonic waves, is renormalized and typically becomes less than the usual cyclotron frequency, which determines the cyclotron resonance. The latter fact was apparently observed in the photoresistance of highly mobile GaAs quantum wells, in which two-dimensional electrons form a viscous fluid.

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YANG, JIN-WEI, YI-PO ZHANG, XU LI, XIAN-YING SONG, GUO-LIANG YUAN, MIN LIAO, LI-QUN HU, SHI-YAO LIN et QING-WEI YANG. « Suppression of runaway electrons during electron cyclotron resonance heating on HL-2A tokamak ». Journal of Plasma Physics 76, n^o 1 (10 septembre 2009) : 75–85. http://dx.doi.org/10.1017/s0022377809990250.

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AbstractThe statistical analysis of heating effect and the cross-correlation analysis of both electron temperature and loop voltage have been done during electron cyclotron resonance heating (ECRH). The behavior of runaway electrons in the flat-top phase during ECRH are analyzed using experimental data. It is shown that the runaway population is indeed suppressed or even quenched when the toroidal electric field ET is reduced below the threshold electric field Eth by high-power and long-duration ECRH. The physical mechanism of runaway suppression is explored by the resonant interaction between the electron cyclotron waves and the energetic runaway electrons.

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Robinson, P. A. « Thermal effects on parallel-propagating electron cyclotron waves ». Journal of Plasma Physics 37, n^o 1 (février 1987) : 149–62. http://dx.doi.org/10.1017/s0022377800012058.

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Thermal effects on the dispersion of right-handed (RH) electron cyclotron waves propagating parallel to a uniform, ambient magnetic field are investigated in the strictly non-relativistic (‘classical’) and weakly relativistic approximations for real frequency and complex wave vector. In each approximation, the two branches of the RH mode reconnect near the cyclotron frequency as the plasma temperature is increased or the density is lowered. This reconnection occurs in a manner different from that previously assumed at parallel propagation and from that at perpendicular propagation, giving rise to a new mode near the cold plasma cut-off frequency ωxC. For both parallel and perpendicular propagation, it is noted that reconnection occurs approximately when the cyclotron line-width equals the width of the stop-band in the cold plasma dispersion relation. Inclusion of weakly relativistic effects is found to be necessary for quantitative calculations and for an accurate treatment of the new mode near ωxC. Weakly relativistic effects also modify the analytic properties of the dispersion relation so as to introduce a new family of weakly damped and undamped solutions.

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22

Farina, Daniela. « Relativistic Dispersion Relation of Electron Cyclotron Waves ». Fusion Science and Technology 53, n^o 1 (janvier 2008) : 130–38. http://dx.doi.org/10.13182/fst08-a1660.

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Shukla, P. K., et L. Stenflo. « Three-dimensional modulation of electron-cyclotron waves ». Physics of Fluids 29, n^o 8 (1986) : 2479. http://dx.doi.org/10.1063/1.865541.

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Singh, D. P., U. P. Singh et R. P. Singh. « Limiting wave growth for electron cyclotron waves ». Earth, Moon, and Planets 64, n^o 2 (février 1994) : 145–54. http://dx.doi.org/10.1007/bf00604486.

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Tanaka, Masayoshi, Ryuji Nishimoto, Seiichiro Higashi, Nobuhiro Harada, Takeshi Ohi, Akio Komori et Yoshinobu Kawai. « Overdense Plasma Production Using Electron Cyclotron Waves ». Journal of the Physical Society of Japan 60, n^o 5 (15 mai 1991) : 1600–1607. http://dx.doi.org/10.1143/jpsj.60.1600.

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Lakhina, G. S., B. T. Tsurutani et J. Pickett. « Association of Alfvén waves and proton cyclotron waves with electrostatic bipolar pulses : magnetic hole events observed by Polar ». Nonlinear Processes in Geophysics 11, n^o 2 (14 avril 2004) : 205–13. http://dx.doi.org/10.5194/npg-11-205-2004.

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Abstract. Two magnetic hole events observed by Polar on 20 May 1996 when it was in the polar cap/polar cusp boundary layer are studied. Low-frequency waves, consisting of nonlinear Alfvén waves and large amplitude (±14nT peak-to-peak) obliquely propagating proton cyclotron waves (with frequency f~0.6 to 0.7 fcp), accompanied by electric bipolar pulses (electron holes) and electron heating have been observed located within magnetic holes. It is shown that low-frequency waves can provide free energy to drive some high frequency instabilities which saturate by trapping electrons, thus, leading to the generation of electron holes.

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Sugawa, Masao, et Reiji Sugaya. « Nonlinear Interaction between Electrostatic Electron Cyclotron Harmonic Waves and Electrons ». Journal of the Physical Society of Japan 54, n^o 4 (15 avril 1985) : 1339–47. http://dx.doi.org/10.1143/jpsj.54.1339.

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Roth, I., M. Temerin et M. K. Hudson. « Resonant enhancement of relativistic electron fluxes during geomagnetically active periods ». Annales Geophysicae 17, n^o 5 (31 mai 1999) : 631–38. http://dx.doi.org/10.1007/s00585-999-0631-2.

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Abstract. The strong increase in the flux of relativistic electrons during the recovery phase of magnetic storms and during other active periods is investigated with the help of Hamiltonian formalism and simulations of test electrons which interact with whistler waves. The intensity of the whistler waves is enhanced significantly due to injection of 10-100 keV electrons during the substorm. Electrons which drift in the gradient and curvature of the magnetic field generate the rising tones of VLF whistler chorus. The seed population of relativistic electrons which bounce along the inhomogeneous magnetic field, interacts resonantly with the whistler waves. Whistler wave propagating obliquely to the magnetic field can interact with energetic electrons through Landau, cyclotron, and higher harmonic resonant interactions when the Doppler-shifted wave frequency equals any (positive or negative) integer multiple of the local relativistic gyrofrequency. Because the gyroradius of a relativistic electron may be the order of or greater than the perpendicular wavelength, numerous cyclotron, harmonics can contribute to the resonant interaction which breaks down the adiabatic invariant. A similar process diffuses the pitch angle leading to electron precipitation. The irreversible changes in the adiabatic invariant depend on the relative phase between the wave and the electron, and successive resonant interactions result in electrons undergoing a random walk in energy and pitch angle. This resonant process may contribute to the 10-100 fold increase of the relativistic electron flux in the outer radiation belt, and constitute an interesting relation between substorm-generated waves and enhancements in fluxes of relativistic electrons during geomagnetic storms and other active periods.Key words. Magnetospheric physics (energetic particles · trapped; plasma waves and instabilities; storms and substorms)

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James, Litty, Lalita Jassal et V. K. Tripathi. « Whistler and electron-cyclotron instabilities in a plasma duct ». Journal of Plasma Physics 54, n^o 1 (août 1995) : 119–28. http://dx.doi.org/10.1017/s0022377800018377.

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A gyrating electron beam propagating through a planar plasma duct can excite a whistler wave or an electron-cyclotron wave, depending on the plasma- density profile of the duct and the energy of the beam. The gyrational motion of the electron beam supplies energy to the wave. In the case of a whistler wave the interaction occurs via coupling of the fast cyclotron beam mode (ω ≈ k2vb + ωc/γ0) to the electromagnetic whistler mode through the Weibel instability mechanism, whereas for an electron-cyclotron wave the coupling is through the negative-mass instability mechanism. It is seen that there exist two diflerent beam-energy regimes for excitation of these waves. The growth rate and the efficiency of conversion for both waves are calculated for typical parameters of a gyrotron and a large-orbit gyrotron.

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Willes, A. J., et P. A. Robinson. « Electron-Cyclotron maser emission from streaming distributions ». Journal of Plasma Physics 51, n^o 1 (février 1994) : 75–93. http://dx.doi.org/10.1017/s0022377800017402.

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Motivated by the need to explain observed elliptically polarized emission from Jupiter, the mechanism of electron-cyclotron maser emission is considered for drifting electron distributions, where the electrons stream with a non-zero mean velocity parallel to the magnetic field lines. An analytical expression for the semirelativistic growth rate is derived and its properties analysed in detail for waves generated in the magneto-ionic modes. The main features of the growth rate are discussed, on the basis of a geometric analysis using resonant ellipses.

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Yao, Xin, Patricio A. Muñoz, Jörg Büchner, Jan Benáček, Siming Liu et Xiaowei Zhou. « Wave Emission of Nonthermal Electron Beams Generated by Magnetic Reconnection ». Astrophysical Journal 933, n^o 2 (1 juillet 2022) : 219. http://dx.doi.org/10.3847/1538-4357/ac7141.

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Abstract Magnetic reconnection in solar flares can efficiently generate nonthermal electron beams. The energetic electrons can, in turn, cause radio waves through microscopic plasma instabilities as they propagate through the ambient plasma along the magnetic field lines. We aim at investigating the wave emission caused by fast-moving electron beams with characteristic nonthermal electron velocity distribution functions (EVDFs) generated by kinetic magnetic reconnection: two-stream EVDFs along the separatrices and in the diffusion region, and perpendicular crescent-shaped EVDFs closer to the diffusion region. For this purpose, we utilized 2.5D fully kinetic Particle-In-Cell code simulations in this study. We found the following: (1) the two-stream EVDFs plus the background ions are unstable to electron/ion (streaming) instabilities, which cause ion-acoustic waves and Langmuir waves due to the net current. This can lead to multiple-harmonic plasma emission in the diffusion region and the separatrices of reconnection. (2) The perpendicular crescent-shaped EVDFs can cause multiple-harmonic electromagnetic electron cyclotron waves through the electron cyclotron maser instabilities in the diffusion region of reconnection. Our results are applicable to diagnose the plasma parameters, which are associated to magnetic reconnection in solar flares by means of radio wave observations.

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Kaur, Rajbir, R. S. Pandey, S. Kumar et B. S. Tomar. « ELECTROMAGNETIC ELECTRON-CYCLOTRON WAVES WITH AC FIELD IN THE MAGNETOSPHERE ». JOURNAL OF ADVANCES IN PHYSICS 5, n^o 2 (6 septembre 2014) : 757–66. http://dx.doi.org/10.24297/jap.v5i2.1938.

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In this paper the effect of externally injected beam of cold electrons on electromagnetic electron-cyclotron (EMEC) waves in the magnetosphere has been discussed. The investigation is conducted using the methodology of characteristic solution and considering kappa distribution function in the presence of AC field.Â The objective of present study is to examine the variation in growth rate of EMEC waves when temperature anisotropy, magnitude of AC field and number density of energetic particles varies. It is inferred that EMEC waves grow more significantly when propagating oblique to magnetic field direction rather than parallel to magnetic field direction. Also that as the temperature anisotropy and number density of background plasma increases, growth rate of EMEC waves increases.

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Robinson, P. A. « Electron cyclotron waves : dispersion and accessibility conditions in isotropic and anisotropic plasmas ». Journal of Plasma Physics 35, n^o 2 (avril 1986) : 187–207. http://dx.doi.org/10.1017/s0022377800011272.

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Dispersion and accessibility conditions for electron cyclotron waves are investigated for arbitrary weakly relativistic plasmas and for specific isotropic and loss-cone distributions. The transition between the cold plasma and vacuum dispersion relations is investigated as a function of temperature and density. The behaviour of mode structure (including mode coupling), cut-offs and resonances are also examined. Generalizations are obtained of earlier results which indicate that access by extraordinary waves to regions nearthe cyclotron layer from the low-field side is easier in weakly relativistic plasmas than predicted by cold plasma theory because of a reduction in the cut-off frequency of the fast extraordinary mode. This effect is found to be more pronounced in loss-cone distributions than in isotropic distributions, permitting access at temperatures considerably lower than those predicted in the isotropic case. Extra loss-cone modes are found to appear near the cyclotron frequency in loss-cone plasmas which also exhibit instabilities near the cyclotron harmonics.

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Ito, K., Y. Kiwamoto, T. Saito et Y. Tatematsu. « Strong narrow-band electron cyclotron emission from a mirror plasma heated by electron cyclotron waves ». Physics of Plasmas 7, n^o 12 (décembre 2000) : 4923–30. http://dx.doi.org/10.1063/1.1322556.

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Cavalcanti, C. J. H., R. S. Schneider et L. F. Ziebell. « Electron-cyclotron absorption by inhomogeneous current-carrying plasmas ». Journal of Plasma Physics 52, n^o 2 (octobre 1994) : 195–214. http://dx.doi.org/10.1017/s0022377800017864.

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We consider effects of inhomogeneity on the absorption of high-frequency electromagnetic waves, propagating at arbitrary angles relative to the magnetic field, by current-carrying plasmas. An inhomogeneous current is assumed to be immersed in an otherwise homogeneous background, and the absorption of fundamental electron-cyclotron waves is discussed, with emphasis on the dependence of the inhomogeneity effect on wave frequency and angle of propagation.

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Huang, S. Y., M. Zhou, X. H. Deng, Z. G. Yuan, Y. Pang, Q. Wei, W. Su, H. M. Li et Q. Q. Wang. « Kinetic structure and wave properties associated with sharp dipolarization front observed by Cluster ». Annales Geophysicae 30, n^o 1 (9 janvier 2012) : 97–107. http://dx.doi.org/10.5194/angeo-30-97-2012.

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Abstract. Multiple dipolarization fronts (DFs) were observed by Cluster spacecraft in the magnetotail during a substorm. These DFs were kinetic structures, embedded in the bursty plasma flow, and moved earthward (mainly) and dawnward. Intense electric field, parallel and perpendicular currents were detected in the DF layer. These front layers were energy dissipation region (load region) where the energy of electromagnetic fields were transferred to the plasma thermal and kinetic energy. This dissipation was dominated by electrons. There were enhancements of plasma waves around the DF region: wavelet results show that wave activities around the ion cyclotron frequency in the front layer were generated by Alfvén ion cyclotron instability; whistler waves were also detected before, during and after the DFs, which are triggered by electron temperature anisotropy and coincident with enhancement of energetic electron fluxes. The observation of these waves could be important for the understanding of evolution of DF and electron energization during the substorm. We discuss the generation mechanism of the DFs and suggest that these DFs were generated in the process of transient reconnection, and then traveled toward the Earth.

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Orefice, A. « Resonant interaction of electron cyclotron waves with a plasma containing arbitrarily drifting suprathermal electrons ». Journal of Plasma Physics 34, n^o 2 (octobre 1985) : 319–26. http://dx.doi.org/10.1017/s0022377800002890.

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A relativistic treatment of the plasma dispersion functions and of the dielectric tensor for electron cyclotron electromagnetic waves is given for non-thermal plasmas where the electron distribution function can be represented as a combination of Maxwellians with arbitrary drifts along the magnetic field.

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Sauvaud, J. A., M. Parrot et E. Slominska. « Comment on "Comparative study on earthquake and ground based transmitter induced radiation belt electron precipitation at middle latitude" ; by Sideropoulos et al. (2011) ». Natural Hazards and Earth System Sciences Discussions 1, n^o 4 (26 juillet 2013) : 3553–75. http://dx.doi.org/10.5194/nhessd-1-3553-2013.

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Abstract. We show that many, if not all, electron bursts claimed to be earthquake precursors by Sideropoulos et al. (2011) are due to the cyclotron resonance of electrons with monochromatic waves from VLF transmitters. The geographic distribution of the VLF-related electron bursts is established during a period in 2007, when the powerful NWC transmitter is off.

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Castejón, F., C. Alejaldre et J. A. Coarasa. « Current drive by electron cyclotron waves in stellarators ». Physics of Fluids B : Plasma Physics 4, n^o 11 (novembre 1992) : 3689–97. http://dx.doi.org/10.1063/1.860376.

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Hoekzema, J. A. « Plasma Heating and Current Drive : Electron Cyclotron Waves ». Fusion Technology 37, n^o 2T (mars 2000) : 163–69. http://dx.doi.org/10.13182/fst00-a11963211.

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Yang, Kwang‐Sup. « Coupled transverse modulational instability of electron cyclotron waves ». Physics of Plasmas 2, n^o 3 (mars 1995) : 678–85. http://dx.doi.org/10.1063/1.871419.

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Esposito, B., G. Granucci, M. Maraschek, S. Nowak, E. Lazzaro, L. Giannone, A. Gude et al. « Disruption avoidance by means of electron cyclotron waves ». Plasma Physics and Controlled Fusion 53, n^o 12 (14 novembre 2011) : 124035. http://dx.doi.org/10.1088/0741-3335/53/12/124035.

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Prater, R. « Heating and current drive by electron cyclotron waves ». Physics of Plasmas 11, n^o 5 (mai 2004) : 2349–76. http://dx.doi.org/10.1063/1.1690762.

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Viktorov, M., I. Izotov, E. Kiseleva, A. Polyakov, S. Vybin et V. Skalyga. « Kinetic whistler instability in a mirror-confined plasma of a continuous ECR ion source ». Physics of Plasmas 30, n^o 2 (février 2023) : 022101. http://dx.doi.org/10.1063/5.0133930.

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Kinetic instabilities in a dense plasma of a continuous electron cyclotron resonance (ECR) discharge in a mirror magnetic trap at the Gasdynamic Ion Source for Multipurpose Operation (GISMO) setup are studied. We experimentally define unstable regimes and corresponding plasma parameters, where the excitation of electromagnetic emission is observed, accompanied by the precipitation of energetic electrons from the magnetic trap. A comprehensive experimental study of the precipitating electron energy distribution and plasma electromagnetic emission spectra, together with theoretical estimates of the cyclotron instability increment proves that under the experimental conditions, the observed instability is related to the excitation of whistler-mode waves, which are a driver of losses of energetic electrons from the magnetic trap. The results of this study are important for the further development of the GISMO electron cyclotron resonance ion source facility and for the improvement of its parameters as an ion source. Also, this research on plasma kinetic instabilities is of fundamental interest and provides experimental tools to simultaneously study plasma electromagnetic activity and corresponding changes in a resonant electron energy distribution.

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McKENZIE, JAMES F. « Wave dynamics of an electrojet : generalized Farley–Buneman instability ». Journal of Plasma Physics 73, n^o 5 (octobre 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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Li, T. M., C. Li, W. J. Ding et P. F. Chen. « Particle-in-cell Simulation of ³He Enrichment in Solar Energetic Particle Events ». Astrophysical Journal 922, n^o 1 (1 novembre 2021) : 50. http://dx.doi.org/10.3847/1538-4357/ac2a40.

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Abstract 3He enrichment is one distinctive feature of impulsive solar energetic particle events. This study is designed to investigate the process of plasma wave–particle resonance, which plays a key role in selectively accelerating heavy ions. We apply a 1.5 dimensional particle-in-cell simulation to model the electron-beam–plasma interaction that generates electron and ion cyclotron waves, namely proton and 4He cyclotron waves, whose dispersions are dependent on the magnetization parameter α = ω pe/Ωce and the temperature ratio τ = T e /T p . The background particles, e.g., 3He and 4He, resonate with the excited cyclotron waves and experience selective heating or acceleration. Specifically, the resonant modes of 3He ions lead to a more effective acceleration rate compared to those of the 4He ions. The simulation results provide a potential solution for understanding the abundance of heavy ions in the solar wind.

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Ram, Abhay, et Kyriakos Hizanidis. « Radiation pressure by electron cyclotron waves on density fluctuations ». EPJ Web of Conferences 277 (2023) : 01001. http://dx.doi.org/10.1051/epjconf/202327701001.

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The presence of turbulence in the form of large density fluctuations and coherent filamentary structures in the edge region of fusion plasmas has been well documented. Radio frequency waves, launched from structures near the wall of a tokamak, have to propagate through this turbulent plasma before reaching the core. These density fluctuations can reflect, refract, and diffract the electromagnetic waves, thereby modifying the flow of energy and momentum to the core plasma. Conversely, the radiation pressure of the radio frequency waves can modify the turbulence, whether it is in the edge region or in the core. This article examines some consequences of the radiation force induced by electron cyclotron waves in plasmas. The effect of waves on two different representations of density fluctuations are studied. In the first representation, suitable for both edge and core plasmas, it is assumed that a planar interface separates two different density regimes. The physics basis for the radiation force on an interface separating two different scalar dielectric media was first elucidated by Poynting in 1905 [J. H. Poynting, The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science 9, 393-406 (1905)]. Poynting’s results are explained within the context of Snell’s law and Fresnel equations, and, subsequently, extended to magnetized plasmas. The analysis shows that electron cyclotron waves lead to peaking of the density profile – the interface is pushed towards the region of higher density. The planar interface approximation is the basis of Kirchhoff theory [P. Beckmann and A. Spizzichino, The Scattering of Electromagnetic Waves from Rough Surfaces (Artech, Massachusetts, 1987) Chapter 3] used to study wave scattering by turbulent media. In the second representation, appropriate for coherent structures in edge plasmas, the radiation force on a cylindrical filament embedded in a background plasma is determined using the Maxwell stress tensor. A detailed study reveals that the radiation force has a different effect on filaments – those with densities higher than the background density are pulled in towards the source launching the waves, while the lower density filaments are pushed away. The reaction on a filament is large enough to be observed experimentally.

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Hultqvist, Bengt. « On beam-generated electrostatic electron waves in magnetized warm plasma ». Journal of Plasma Physics 34, n^o 3 (décembre 1985) : 435–44. http://dx.doi.org/10.1017/s0022377800002993.

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The linear dispersion relation for electrostatic electron waves is analysed in some detail. A method is described which allows the dispersion equation to be solved and the attenuation rate/growth rate to be derived for waves generated by electrons flowing through a stationary plasma along the field lines of a static magnetic field. The solution is derived from three simple curves (one for each of the real and imaginary parts of the dispersion equation and one for the growth rate) and is applicable for any propagation angle relative to the magnetic field lines (below a limiting value), for any wavelength, any magnetic field intensity, any electron density and temperature and any flow speed of a beam plasma component. The effects of cyclotron resonance start to be significant at an angle from the direction of the magnetostatic field lines that depends on most of the variables mentioned, but only in one specific combination, which is the measure of the ratio between thermal velocity of the electrons and the phase velocity of the wave at the cyclotron frequency. In contrast to numerical methods, the method described here provides a parameterization of the solutions to the dispersion equation and of the growth rate. It gives an overview of the dependencies on the variables in the equation over a large part of parameter space without any other computations than those involved in adjusting scale factors.

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Pasmanik, D. L., V. Y. Trakhtengerts, A. G. Demekhov, A. A. Lyubchich, E. E. Titova, T. Yahnina, M. J. Rycroft, J. Manninen et T. Turunen. « A quantitative model for cyclotron wave-particle interactions at the plasmapause ». Annales Geophysicae 16, n^o 3 (31 mars 1998) : 322–30. http://dx.doi.org/10.1007/s00585-998-0322-4.

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Abstract. The formation of a zone of energetic electron precipitation by the plasmapause, a region of enhanced plasma density, following energetic particle injection during a magnetic storm, is analyzed. Such a region can also be formed by detached cold plasma clouds appearing in the outer magnetosphere by restructuring of the plasmasphere during a magnetic storm. As a mechanism of precipitation, wave-particle interactions by the cyclotron instability between whistler-mode waves and electrons are considered. In the framework of the self-consistent equations of quasi-linear plasma theory, the distribution function of trapped electrons and the electron precipitation pattern are found. The theoretical results are compared with experimental data obtained from NOAA satellites.Key words. Magnetospheric physics · Energetic particles · Precipitating and trapped · Plasma waves and instabilities

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Sauvaud, J. A., M. Parrot et E. Slominska. « Comment on "Comparative study on earthquake and ground based transmitter induced radiation belt electron precipitation at middle latitude", by Sideropoulos et al. (2011) ». Natural Hazards and Earth System Sciences 14, n^o 1 (2 janvier 2014) : 1–9. http://dx.doi.org/10.5194/nhess-14-1-2014.

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Abstract. We show that many, if not all, electron bursts with energy dispersion claimed to be earthquake precursors by Sideropoulos et al. (2011) are due to the cyclotron resonance of electrons with monochromatic waves from VLF transmitters. The geographic distribution of the VLF-related electron bursts is established during a period in 2007, when the powerful NWC transmitter is off and 20 more transmitters are operating.

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