Theory of finite-amplitude electron and ion holes

Bujarbarua, S.; Schamel, H.

doi:10.1017/s0022377800026295

Cited by 133 publications

(82 citation statements)

References 19 publications

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“…For completeness, we mention that solitary ion holes and the corresponding weak double layers are based on the SIAW, 10,22,23 and it would be no surprise if their so-called "dubbed ion-bulk waves" are strongly related, if not identical, to the earlier obtained class of ion hole modes.…”

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confidence: 80%

Comment on “Undamped electrostatic plasma waves” [Phys. Plasmas 19, 092103 (2012)]

Schamel

2013

Physics of Plasmas

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The relevance of linear “corner modes” for the description of coherent electrostatic structures, as proposed by Valentini et al. [Phys. Plasmas 19, 092103 (2012)], is questioned. Coherency in their on-dispersion simulation is instead found to be caused by particle trapping in agreement with Schamel's nonlinear wave model [Phys. Plasmas 19, 020501 (2012)]. The revealed small amplitude structures are hence of cnoidal electron hole type exhibiting vortices in phase space. They are ruled by trapping nonlinearity rather than by linearity or quasi-linear effects, as commonly assumed. Arguments are presented, which give preference to these cnoidal hole modes over Bernstein-Greene-Kruskal modes. To fully account for a realistic theoretical scenario, however, at least four ingredients are mandatory. Several corrections of the conventional body of thought about the proper kinetic wave description are proposed. They may prove useful for the general acceptance of this “new” nonlinear wave concept concerning structure formation, updating several prevailing concepts such as the general validity of a linear wave Ansatz for small amplitudes, as assumed in their paper. It is conjectured that this nonlinear trapping model can be generalized to the vortex structures of similar type found in the more general setting of driven turbulence of magnetized plasmas. They appear as eddies in both, the phase and the position spaces, embedded intermittently on the Debye length scale.

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confidence: 80%

Comment on “Undamped electrostatic plasma waves” [Phys. Plasmas 19, 092103 (2012)]

Schamel

2013

Physics of Plasmas

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“…Similarly as for the electron holes, a special class of solutions can be found by prescribing the ion distribution function for free (E i > 0) and trapped (E i < 0) ions as (Bujarbarua and Schamel, 1981) ,…”

Section: The Dynamics Of Ion Holes In Plasmasmentioning

confidence: 99%

“…About a quarter century ago, Schamel (1971Schamel ( , 1972Schamel ( , 1979Schamel ( , 1986Bujarbarua and Schamel, 1981) presented a theory for ion and electron holes, where a vortex distribution is assigned for the trapped particles, and where the integration over the trapped and untrapped particle species in velocity space gives the particle number density as a function of the electrostatic potential. The potential is then calculated self-consistently from Poisson's equation.…”

Section: Introductionmentioning

confidence: 99%

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The dynamics of electron and ion holes in a collisionless plasma

Eliasson

Shukła

2005

Nonlin. Processes Geophys.

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Abstract. We present a review of recent analytical and numerical studies of the dynamics of electron and ion holes in a collisionless plasma. The new results are based on the class of analytic solutions which were found by Schamel more than three decades ago, and which here work as initial conditions to numerical simulations of the dynamics of ion and electron holes and their interaction with radiation and the background plasma. Our analytic and numerical studies reveal that ion holes in an electron-ion plasma can trap Langmuir waves, due the local electron density depletion associated with the negative ion hole potential. Since the scalelength of the ion holes are on a relatively small Debye scale, the trapped Langmuir waves are Landau damped. We also find that colliding ion holes accelerate electron streams by the negative ion hole potentials, and that these streams of electrons excite Langmuir waves due to a streaming instability. In our Vlasov simulation of two colliding ion holes, the holes survive the collision and after the collision, the electron distribution becomes flat-topped between the two ion holes due to the ion hole potentials which work as potential barriers for low-energy electrons. Our study of the dynamics between electron holes and the ion background reveals that standing electron holes can be accelerated by the selfcreated ion cavity owing to the positive electron hole potential. Vlasov simulations show that electron holes are repelled by ion density minima and attracted by ion density maxima. We also present an extension of Schamel's theory to relativistically hot plasmas, where the relativistic mass increase of the accelerated electrons have a dramatic effect on the electron hole, with an increase in the electron hole potential and in the width of the electron hole. A study of the interaction between electromagnetic waves with relativistic electron holes shows that electromagnetic waves can be both linearly and nonlinearly trapped in the electron hole, which widens further due to the relativistic mass increase and ponderomotive force in the oscillating electromagnetic field. The results of Correspondence to: B. Eliasson (bengt@tp4.rub.de) our simulations could be helpful to understand the nonlinear dynamics of electron and ion holes in space and laboratory plasmas.

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“…We present for the first time a new Langmuir turbulent state in the presence of ion phase-space vortices [15,16,17] that are associated with density holes and bipolar electric fields in collisionless plasmas. Ion phase-space vortices are natural products of ion-beam driven two-stream instabilities, and they play a very important role in laboratory experiments [18,19,20] as well as in the near-earth plasma environment [21,22].…”

Section: Introductionmentioning

confidence: 99%

Trapping of plasmons in ion holes

Shukła

Eliasson

2003

Jetp Lett.

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We present analytical and numerical studies of a new electron plasma wave interaction mechanism, which reveals trapping of Langmuir waves in ion holes associated with nonisothermal ion distribution functions. This Langmuir ion hole interaction is a unique kinetic phenomenon governed by two second nonlinear differential equations in which the Langmuir wave electric field and ion hole potential are coupled in a complex fashion. Numerical analyses of our nonlinearly coupled differential equations exhibit trapping of localized Langmuir wave envelops in the ion hole, which is either standing or moving with sub-or super ion thermal speed. The resulting ambipolar potential of the ion hole is essentially negative, giving rise to bipolar slow electric fields. The present investigation thus offers a new Langmuir wave contraction scenario that has not been rigorously explored in plasma physics

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Theory of finite-amplitude electron and ion holes

Abstract: A complete investigation is presented of the theory of finite-amplitude electron and ion holes which are localized BGK solutions moving near the respective thermal velocities. For their existence, the distribution functions are required to have a minimum in the resonant region.

Cited by 133 publications

References 19 publications

Comment on “Undamped electrostatic plasma waves” [Phys. Plasmas 19, 092103 (2012)]

Comment on “Undamped electrostatic plasma waves” [Phys. Plasmas 19, 092103 (2012)]

The dynamics of electron and ion holes in a collisionless plasma

Trapping of plasmons in ion holes

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