Foundations of Plasma Physics

Holt, E. H.; Haskell, Richard E.; Radin, S.

doi:10.1119/1.1972917

Cited by 17 publications

(12 citation statements)

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“…For large values of k eq. ( 39) yields ω ≈ k 2 and the magnitude of the damping coefficient is seen to decrease rapidly with growing k. This is to be contrasted with what obtains in the case of electrostatic waves in plasmas, where the damping is small for small values of the wave vector k and increases with it, to the point of rendering oscillation impossible for large enough k [8,14]. In plasmas, at small k the phase velocity is very large (infinity in the limit for k → 0) and decreases asymptotically toward thermal velocity as k grows larger; in the present case the opposite is true: phase velocity increases for larger k values.…”

Section: -P3mentioning

confidence: 91%

Wave propagation and “Landau-type” damping from Bohm potential

2008

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From Bohm's interpretation of quantum mechanics, a quantum kinetic equation (QKE) can be derived. It is found that waves propagate in force-free gases of non interacting particles, only due to Bohm potential. In the present article the existence of Landau damping in such propagations is investigated. It is found that the Bohm potential alone gives indeed rise to a damping entirely analogous to the classical Landau damping, both for bosons and for weakly degenerate fermions.

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Section: -P3mentioning

confidence: 91%

Wave propagation and “Landau-type” damping from Bohm potential

2008

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“…The dynamics of the plasma and the potential in the simulation region R s < r < Rma x are studied by self-consistently solving the Poisson equation for the electric potential tI) (r) and timedependent hydrodynamic plasma equations for (1) the ambient electrons, (2) the ionization-produced (i-p) electrons, and (3) ions consisting of both the ambient and the i-p ions. Specifically, we solve the following equations [Holt and Haskell, 1965 Figure 1). The boundary conditions on the plasma fluids are as follows.…”

Section: Theoretical Modelmentioning

confidence: 99%

lonization‐driven plasma dynamics in a high voltage sheath of a conducting body in the ionosphere

Singh¹,

Jaggernauth²

1996

J. Geophys. Res.

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A high‐voltage sheath of a conducting body in space is relevant to several space applications, such as electron beam ejections, charge neutralization on bodies, and the electrodynamic tether. The acceleration of electrons to relatively high energies inside the sheath causes ionization of the neutral gas constituents by electron‐neutral (e‐n) impacts. This in turn greatly modifies the sheath structure, including the dynamics of the charged particles inside the sheath. Artificial neutral gas releases have been used in several space experiments for the purpose of enhancing the electron collection by bodies (electrodes) in space. In this paper, the effects of ionization of a neutral gas on the plasma dynamics and the collection of electrons by a high‐voltage electrode are studied theoretically. The study is based on a one‐dimensional radial model in which time‐dependent hydrodynamic plasma equations are solved self‐consistently with the Poisson equation. The electrons originating from the ambient plasma and those produced by the ionization of the neutral gas are treated as separate fluids. The effects of the ionization on the sheath greatly depend on the neutral gas density. For sufficiently low densities, ionization has hardly any effect on the sheath. In this case, the current collection is given by collisionless sheath theories. For very high densities, collisionless description of the plasma is not valid and the current collection is limited by the e‐n collisions. For moderate densities, the ionization drives several plasma processes in the sheath, which are (1) recurrent sheath expansion, (2) recurrent evolution of potential distribution from a thin sheath to an extended distribution having a double layer and/or a “hump”, (3) formation of oscillatory density structure in the ion density profile near the low potential end of the sheath in a highly nonuniform, expanding, dense plasma, (4) enhancements and disruptions in electron current collection, and (5) plasma expansion with multiple expansion fronts. The oscillatory density structure and the recurrent behavior are interpreted in terms of an ion wave instability driven by counterstreaming electron and ion beams near the low potential end of the sheath. The instability becomes very effective when the plasma density is enhanced by the trapping of the ionization‐produced electrons inside the sheath, because its growth rate γ ∼ωpi, where ω pi is ion plasma frequency. The wave grows as it convects with the expanding ion beam. When the ion wave is amplified because of the enhanced growth rate following a substantial increase in the plasma density by the trapping, the sheath expansion is disrupted and the sheath thins. The continued ionization leads to the further expansion and the recurrent behavior.

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“…Unlike other models which have more than one undetermined parameters and are lack of rigorous derivation, this model is derived rigorously from the collisional Boltzmann equation in a self-consistent manner. [14] It has only one free parameter α, which is included in the effective collisional frequency to describe binary collisions at an atomic level, and its value can be determined by experimental data. Several authors have used the mix model to research indirectly and directly driven implosions and many useful results were obtained.…”

Section: Introductionmentioning

confidence: 99%

Effects of Atomic Mixing in Inertial Confinement Fusion by Multifluid Interpenetration Mix Model

Gu¹,

Ye²

2009

Commun. Theor. Phys.

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The effects of atomic-level mixing are systemically investigated in a multifluid interpenetration mix model, and results are compared with the single-fluid model's simulations and experimental data. It is shown that increasing the model free parameter α, shock Mach number, and the initial density discontinuity makes the mix length and fraction of mixing particle increase, resulting in the lower shock temperatures compared with the results of single-fluid model without mixing. Recent high-compressibility direct-drive spherical implosions on OMEGA are simulated by the interpenetration mix model. The calculations with atomic mixing between fuel and shell match quite well with the observations. Without considering any mixing, the calculated neutron yields and ion temperatures are overpredicted; while inclusion of the interpenetration mix model with the adjustable parameter α could fit the simulated neutron yields and ion temperatures well with experimental data.

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Foundations of Plasma Physics

Cited by 17 publications

References 0 publications

Wave propagation and “Landau-type” damping from Bohm potential

Wave propagation and “Landau-type” damping from Bohm potential

lonization‐driven plasma dynamics in a high voltage sheath of a conducting body in the ionosphere

Effects of Atomic Mixing in Inertial Confinement Fusion by Multifluid Interpenetration Mix Model

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