Ion wave instability in an electrostatic shock

Abas, Siti Sabariah; Gary, S. Peter

doi:10.1088/0032-1028/13/3/009

Cited by 12 publications

(8 citation statements)

References 4 publications

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“…12 We have found good quantitative agreement of our measured initial stability limits with those predicted by the linear theory. We also obtained qualitative agreement with the theoretical linear dispersion relation 10, 13 phase velocity between the two beams. It is difficult to measure the linear dispersion relation accurately since nonlinear effects are important even in the early development of the instability.…”

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confidence: 77%

Measurements of the Self-Stabilization of a Two—Ion-Beam Instability

Baker

1972

Phys. Rev. Lett.

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The self-stabilization of the two-ion-beam instability due to microturbulent ion heating has been measured in a plasma with variable temperature ratio (2.0 < T e /T i < 10.0). When the plasma is unstable, excited ion waves and background microturbulence are observed to grow, saturate, and damp, in conjunction with ion heating. When the plasma is stable, no ion heating is observed. The ion heating e-folding length is may occur in the formation of collisionless shocks.

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confidence: 77%

Measurements of the Self-Stabilization of a Two—Ion-Beam Instability

Baker

1972

Phys. Rev. Lett.

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“…Similarly, the ion acoustic mode of negative phase speed satisfies a) r /k < v Oc < 0 and also remains damped with increasing v 0 (not shown in figure 1). However, as v 0 increases, one of the heavily damped acoustic-like modes mentioned in Fried & Gould (1961) experiences a reduction in its damping rate and, at sufficiently large v 0 , becomes unstable (Abas & Gary 1971). This is also illustrated in figure 1, where this mode corresponds to the mode of smaller phase speed at v 0 > 0.…”

Section: Unmagnetized Plasma Resultsmentioning

confidence: 72%

The ion-ion acoustic instability

1987

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This paper considers the linear theory of ion-acoustic-like instabilities in a homogeneous Vlasov plasma with two ion components, a less dense beam and a more dense core, with a relative drift velocity. Numerical solutions of the full electrostatic dispersion equation are presented, and the properties of the ion–ion acoustic instability are studied in detail. The following properties are demonstrated: (i) At relatively cold beam temperatures, the instability is fluid-like, but it becomes a beam resonant kinetic instability as the beam temperature becomes of the order of the core temperature; (ii) if the mode is unstable, its threshold lies well below the threshold of the electron–ion acoustic instability; (iii) an electron temperature anisotropy T⊥/T‖e > 1 enhances the instability and (iv) at sufficiently large beam-core relative drift speeds, electron magnetization can either detract from or enhance the instability. If field-aligned ion beams are to drive the ion-acoustic-like enhanced fluctuations observed upstream of the Earth's bow shock, the effective beam temperature must be much smaller than values quoted in the literature.

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“…The electrostatic ion beam instability has been considered for many years as a possible mechanism to generate the ionacoustic-like waves in space and therefore the necessary turbulent diss!pation in collisionless shocks [Abas and Gary, 1971; Papadopoulos et al, 1971;Gary, 1978;Lemons et al, 1979;Formisano and Torbert, 1982;Fuselier and Gurnett, 1984]. Nevertheless, if we adhere to field-aligned waves, we encounter some severe difficulties, as shown by Lemons e t al.…”

Section: Linear Theorymentioning

confidence: 99%

Ion‐acoustic‐like waves excited by the reflected ions at the Earth's bow shock

Akimoto

Winske

1985

J. Geophys. Res.

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Some model distributions based on recent observations and simulations of the plasma at the earth's bow shock are found to be unstable to obliquely propagating electrostatic instabilities. The model distributions consist of either an ion beam or an ion velocity ring accompanied by a bi‐Maxwellian background ion distribution and a flattop electron distribution. Ion anisotropies and nonthermal electrons are capable of significantly lowering the threshold of the ion beam instability. The generated waves share many properties in common with the ion acoustic waves that have been observed at the earth's bow shock. The results also indicate the importance of an anisotropy in the background ion velocity distribution in identifying sources of the ion‐acoustic‐like waves observed in the ion foreshock and the solar wind.

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Ion wave instability in an electrostatic shock

Cited by 12 publications

References 4 publications

Measurements of the Self-Stabilization of a Two—Ion-Beam Instability

Measurements of the Self-Stabilization of a Two—Ion-Beam Instability

The ion-ion acoustic instability

Ion‐acoustic‐like waves excited by the reflected ions at the Earth's bow shock

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