Numerical study of electrostatic electron cyclotron harmonic waves due to Maxwellian ring velocity distributions

Umeda, Takayuki

doi:10.1186/bf03352068

Cited by 6 publications

(5 citation statements)

References 31 publications

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“…. 15 It has been shown, by the direct comparison with full particle simulations, that the obtained "numerical" linear growth rates of electron cyclotron harmonic waves are in excellent agreement. The Maxwellian ring velocity distribution also results in an anisotropy of the temperature components parallel and perpendicular to the magnetic field direction, which becomes a free energy source for electromagnetic waves.…”

Section: Introductionmentioning

confidence: 58%

“…We extended the previous electrostatic linear a) Electronic mail: umeda@stelab.nagoya-u.ac.jp. 15 to an electromagnetic one. Results of the linear dispersion analysis are compared against full particle simulation results.…”

Section: Introductionmentioning

confidence: 97%

“…15, y is taken from maxð0; b s À 5Þ to b s þ 5, and this interval is broken into 100 pieces. Then Simpson's rule is used for the numerical integration over y shown in Eqs.…”

Section: Introductionmentioning

confidence: 99%

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A numerical electromagnetic linear dispersion relation for Maxwellian ring-beam velocity distributions

et al. 2012

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A positive slope in a velocity distribution function perpendicular to the ambient magnetic field, such as due to a loss cone or ring velocity distribution, can become a free energy source for the excitation of various plasma waves. Since there exists no analytic expression for integrals of Maxwellian ring velocity distribution functions, their linear properties have previously been studied using several approximations or modeled distributions. In this paper, a numerical method for analyzing the linear dispersion relation for Maxwellian ring-beam velocity distributions is developed. The obtained linear properties are confirmed by direct comparison with full particle simulation results. V C 2012 American Institute of Physics. [http://dx.

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Section: Introductionmentioning

confidence: 58%

Section: Introductionmentioning

confidence: 97%

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A numerical electromagnetic linear dispersion relation for Maxwellian ring-beam velocity distributions

et al. 2012

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“…Nevertheless, several studies have employed numerical integration techniques to examine plasma instabilities driven by the ring velocity distribution [ McClements et al , ; Umeda et al , ; Umeda , ]. One of the most general formulations has been provided by Umeda et al [] who, applying the formulation to the analysis of electrostatic electron cyclotron harmonic waves driven by the ring distribution of electrons, showed that the linear instabilities and simulated waves have excellent agreement.…”

Section: Introductionmentioning

confidence: 99%

Fast magnetosonic waves driven by shell velocity distributions

Min

Liu

2015

JGR Space Physics

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Using linear dispersion theory and particle‐in‐cell simulations, we explore the ion Bernstein instability driven by the shell‐type ion velocity distribution which is related to the excitation of fast magnetosonic waves in the terrestrial magnetosphere. We first demonstrate a novel idea to construct the shell velocity distribution out of multiple Maxwellian ring‐beam velocity distributions. Applying this technique, we find that the convergence of the linear theory instability can be achieved with only a moderate number of ring‐beam components. In order to prove that such an approximation is legitimate and the linear theory instabilities evaluated are indeed valid, we use the exact shell distribution to carry out a number of one dimensional particle‐in‐cell simulations corresponding to multiple wave propagation angles adjacent to the direction at which the most unstable waves are expected to grow. The agreement between the linear dispersion analysis and the simulation results is generally very good: enhanced waves are organized along the linear theory dispersion curves in the frequency‐wave number space, and relative wave amplitudes are ordered as the linear theory growth rates very well. However, the simulations show a few extra branches that are not expected from the linear dispersion analysis. A close examination of these extra branches suggests that they are not simulation artifacts and particularly related to the ring/shell‐type distributions with large ring/shell speed (v>∼1.5 vA, where vA is the Alfvén speed). In addition, our results show that substantial wave growth can occur at nonintegral harmonics of the proton cyclotron frequency at wave normal angles substantially far away from the perpendicular direction, which may provide an alternative explanation of the off‐harmonic peaks of some fast magnetosonic waves observed in space.

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“…Recent laboratory experiments [27,28] using a mirror confined plasma have shown a number of different instabilities and emissions, including oscillations near the second electron cyclotron harmonic attributed to the presence of thermal ring distributions [12]. Theoretical and numerical studies have been carried out of thermal ring electron distributions [30,31] and of a maser-beam instability of Bernstein waves [29]. Particle-in-cell simulations have been used to study Bernstein waves [32] and instabilities for combinations of ring and core populations [33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Electrostatic electron cyclotron instabilities near the upper hybrid layer due to electron ring distributions

Eliasson

Speirs

Daldorff

2016

Plasma Phys. Control. Fusion

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A theoretical study is presented of the electrostatic electron cyclotron instability involving Bernstein modes in a magnetized plasma. The presence of a tenuous thermal ring distribution in a Maxwellian plasma decreases the frequency of the upper hybrid branch of the electron Bernstein mode until it merges with the nearest lower branch with a resulting instability. The instability occurs when the upper hybrid frequency is somewhat above the third, fourth, and higher electron cyclotron harmonics, and gives rise to a narrow spectrum of waves around the electron cyclotron harmonic nearest to the upper hybrid frequency. For a tenuous cold ring distribution together with a Maxwellian distribution an instability can take place also near the second electron cyclotron harmonic. Noise-free Vlasov simulations are used to assess the theoretical linear growth-rates and frequency spectra, and to study the nonlinear evolution of the instability. The relevance of the results to laboratory and ionospheric heating experiments is discussed.

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Numerical study of electrostatic electron cyclotron harmonic waves due to Maxwellian ring velocity distributions

Cited by 6 publications

References 31 publications

A numerical electromagnetic linear dispersion relation for Maxwellian ring-beam velocity distributions

A numerical electromagnetic linear dispersion relation for Maxwellian ring-beam velocity distributions

Fast magnetosonic waves driven by shell velocity distributions

Electrostatic electron cyclotron instabilities near the upper hybrid layer due to electron ring distributions

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