POP Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter UniPHY Group iResearch App Facebook

Search Issue | RSS Feeds RSS
Previous Issue Next Issue

May 2005

Volume 12, Issue 5, Articles (05xxxx)

Page 1 of 8 Pages Next Page | Jump to Page
back to top
RSS Feeds

Explicit threshold of the toroidal ion temperature gradient mode instability

I. Sandberg

Phys. Plasmas 12, 050701 (2005); http://dx.doi.org/10.1063/1.1883179 (4 pages) | Cited 5 times

Online Publication Date: 7 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The explicit stability threshold of the toroidal ion temperature gradient mode instability is analytically derived using the standard reactive fluid model. It is shown that in the peak density region, the threshold gets significantly smaller due to finite ion Larmor radius effects, and the marginal unstable modes acquire finite wavelengths.
Show PACS
52.35.Qz Microinstabilities (ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron, etc.)
52.55.Fa Tokamaks, spherical tokamaks
52.30.-q Plasma dynamics and flow
52.25.Fi Transport properties
52.40.Hf Plasma-material interactions; boundary layer effects

The origin of the long time correlations of the density fluctuations in the scrape-off layer of the Tore Supra Tokamak

P. Devynck, P. Ghendrih, and Y. Sarazin

Phys. Plasmas 12, 050702 (2005); http://dx.doi.org/10.1063/1.1894399 (4 pages) | Cited 5 times

Online Publication Date: 2 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
It is shown that intermittent density bursts observed in the scrape-off layer of Tore Supra [ J. Jacquinot, Nucl. Fusion 43, 1583 (2003) ] are detected in packs on the probe. In such a pack, typically two to three bursts are separated by time intervals smaller than the mean separation time. The long tails above 50 μs observed on the autocorrelation function of the density fluctuations are found to be the temporal correlation between the individual bursts within their pack. Packs of density bursts can be detected in two limiting states of the turbulence: when the coupling between density and potential is strong and large density bursts split during their radial propagation or at the opposite when the coupling is weak so that different density bursts can propagate radially along the potential valleys. The lack of spatial resolution of the diagnostic does not allow to discriminate between the two mechanisms.
Show PACS
52.25.Gj Fluctuation and chaos phenomena
52.25.Fi Transport properties
52.40.Hf Plasma-material interactions; boundary layer effects
52.55.Fa Tokamaks, spherical tokamaks
52.70.Ds Electric and magnetic measurements
52.35.Ra Plasma turbulence

Excitation of the toroidicity-induced shear Alfvén eigenmode by toroidal ion-temperature-gradient mode turbulence

V. S. Marchenko

Phys. Plasmas 12, 050703 (2005); http://dx.doi.org/10.1063/1.1897387 (3 pages)

Online Publication Date: 5 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
It is shown that the toroidicity-induced shear Alfvén eigenmode (TAE) with low mode numbers can be excited as a result of the modulational instability of the short wavelength toroidal ion-temperature-gradient mode turbulence. This instability seems to be responsible for the TAE excitation in Ohmically heated discharges at ASDEX Upgrade tokamak [ M. Maraschek, S. Günter, T. Kass, B. Scott, and H. Zohm, Phys. Rev. Lett. 79, 4186 (1997) ].
Show PACS
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Ra Plasma turbulence
52.55.Fa Tokamaks, spherical tokamaks
52.25.-b Plasma properties
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.80.-s Electric discharges
back to top
RSS Feeds
back to top Basic Plasma Phenomena, Waves, Instabilities

Spatial Landau damping in plasmas with three-dimensional κ distributions

J. J. Podesta

Phys. Plasmas 12, 052101 (2005); http://dx.doi.org/10.1063/1.1885474 (10 pages) | Cited 12 times

Online Publication Date: 7 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The increase in linear Landau damping in κ-distributed plasmas compared to thermal equilibrium plasmas is studied by solving a boundary value problem for the spatially damped plasma waves generated by a planar grid electrode with an applied time harmonic potential. Solutions are computed for the plasma potential versus the distance from the electrode for different values of the parameter κ (kappa). The velocity parameter v0 of the distribution function is chosen so that, as the parameter κ varies, the kinetic temperature of the plasma remains constant. The exact solutions of this problem are also compared to approximate solutions derived from the theory of normal modes, that is, from the roots of the dispersion relation. This model problem demonstrates the significant increase in Landau damping by electrons which occurs for small values of the parameter κ.
Show PACS
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.25.Dg Plasma kinetic equations
52.20.-j Elementary processes in plasmas
52.25.Mq Dielectric properties

Fluid formalism for collisionless magnetized plasmas

J. J. Ramos

Phys. Plasmas 12, 052102 (2005); http://dx.doi.org/10.1063/1.1884128 (14 pages) | Cited 31 times

Online Publication Date: 13 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A comprehensive analysis of the finite-Larmor-radius (FLR) fluid moment equations for collisionless magnetized plasmas is presented. It is based on perturbative but otherwise general solutions for the second and third rank fluid moments (the stress and stress flux tensors), with closure conditions still to be specified on the fourth rank moment. The single expansion parameter is the ratio between the largest among the gyroradii and any other characteristic length, which is assumed to be small but finite in a magnetized medium. This formalism allows a complete account of the gyroviscous stress, the pressure anisotropy, and the anisotropic heat fluxes, and is valid for arbitrary magnetic geometry, arbitrary plasma pressure, and fully electromagnetic nonlinear dynamics. As the result, very general yet notably compact perturbative systems of FLR collisionless fluid equations, applicable to either fast (sonic or Alfvénic) or slow (diamagnetic) motions, are obtained.
Show PACS
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
52.25.Xz Magnetized plasmas
52.25.Fi Transport properties

Electron inertia effect on small amplitude solitons in a weakly relativistic two-fluid plasma

Khushvant Singh, Vinod Kumar, and Hitendra K. Malik

Phys. Plasmas 12, 052103 (2005); http://dx.doi.org/10.1063/1.1894398 (9 pages) | Cited 28 times

Online Publication Date: 20 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
One-dimensional evolution of solitons in a two-fluid plasma having weakly relativistic streaming ions and electrons is studied through usual Korteweg–de Vries equation under the effect of electron inertia. Although fast and slow ion acoustic modes are possible in such a plasma, only the fast mode corresponds to the soliton propagation for a particular range of velocity difference of ions and electrons. This range depends upon the ratios of mass and temperature of the ions and electrons. The effect of electron inertia on the propagation characteristics of the soliton is studied for typical values of the speed and temperature of the ions and electrons and it is found that this effect is dominant over the relativistic effect and the effect of ion temperature.
Show PACS
52.35.Sb Solitons; BGK modes
52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.30.Ex Two-fluid and multi-fluid plasmas
52.25.Fi Transport properties
52.27.Ny Relativistic plasmas

Surface waves in anisotropic Maxwellian plasmas

Myoung-Jae Lee and Hee J. Lee

Phys. Plasmas 12, 052104 (2005); http://dx.doi.org/10.1063/1.1895668 (6 pages) | Cited 4 times

Online Publication Date: 28 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Dispersion relation of electromagnetic surface waves propagating on the interface between a vacuum and anisotropic Maxwellian plasmas is derived from Vlasov–Maxwell equations. By taking the limit of infinite speed of light in the electromagnetic dispersion relation, we derived dispersion relation of electrostatic surface waves, and we find that plasmas with equilibrium distribution f0α = (mα/2πTα)exp{−[mα(vx2+vy2)]/2Tα}δ(vz) (α = e,i; electrons and ions), where the z direction is normal to the interface, can be unstable to perturbations of ion-acoustic surface wave type.
Show PACS
52.40.Db Electromagnetic (nonlaser) radiation interactions with plasma
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.35.Qz Microinstabilities (ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron, etc.)
52.35.Dm Sound waves
52.25.Fi Transport properties

Effects of finite sized charge on downstream wake patterns

Anirban Bose and M. S. Janaki

Phys. Plasmas 12, 052105 (2005); http://dx.doi.org/10.1063/1.1893585 (6 pages)

Online Publication Date: 2 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Finite sized charged particles introduced into streaming dusty plasmas produce wake patterns in the downstream region. The structure of the wake potential is found to depend on values of the charge size and Mach number M, where M is the ratio of the flow speed to the dust acoustic speed.
Show PACS
52.27.Lw Dusty or complex plasmas; plasma crystals
52.30.-q Plasma dynamics and flow
52.35.Dm Sound waves

Cylindrical and spherical ion acoustic waves in a plasma with nonthermal electrons and warm ions

Biswajit Sahu and Rajkumar Roychoudhury

Phys. Plasmas 12, 052106 (2005); http://dx.doi.org/10.1063/1.1897714 (5 pages) | Cited 2 times

Online Publication Date: 2 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using the reductive perturbation technique, nonlinear cylindrical and spherical Korteweg–de Vries (KdV) and modified KdV equations are derived for ion acoustic waves in an unmagnetized plasma consisting of warm adiabatic ions and nonthermal electrons. The effects of nonthermally distributed electrons on cylindrical and spherical ion acoustic waves are investigated. It is found that the nonthermality has a very significant effect on the nature of ion acoustic waves.
Show PACS
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.27.Lw Dusty or complex plasmas; plasma crystals
52.35.Sb Solitons; BGK modes

Eigenmode response to driven magnetic reconnection in a collisionless plasma

J. Egedal, W. Fox, M. Porkolab, and A. Fasoli

Phys. Plasmas 12, 052107 (2005); http://dx.doi.org/10.1063/1.1898205 (9 pages) | Cited 5 times

Online Publication Date: 5 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The collisionless plasma of the Versatile Toroidal Facility experiment [ J. Egedal, A. Fasoli, M. Porkolab, and D. Tarkowski, Rev. Sci. Instrum. 71, 3351 (2000) ], applied to the study of magnetic reconnection, exhibits a global eigenmode response during which the reconnection rate and the current channel oscillate. The present paper describes experiments tailored for investigating this eigenmode response. It is found that the oscillatory plasma behavior is linked to ion-polarization currents and associated electron currents that flow to maintain quasineutrality within the active reconnection region. A theoretical model is developed which describes the eigenmode response and accounts for the temporal evolution of the measured profiles of key plasma parameters.
Show PACS
52.35.Vd Magnetic reconnection
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.55.Lf Field-reversed configurations, rotamaks, astrons, ion rings, magnetized target fusion, and cusps
52.55.Jd Magnetic mirrors, gas dynamic traps
52.25.Fi Transport properties

Measurements of classical transport of fast ions

L. Zhao, W. W. Heidbrink, H. Boehmer, R. McWilliams, D. Leneman, and S. Vincena

Phys. Plasmas 12, 052108 (2005); http://dx.doi.org/10.1063/1.1905863 (9 pages) | Cited 9 times

Online Publication Date: 5 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
To study the fast-ion transport in a well controlled background plasma, a 3-cm diameter rf ion gun launches a pulsed, ∼ 300 eV ribbon shaped argon ion beam parallel to or at 15° to the magnetic field in the Large Plasma Device (LAPD) [ W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991) ] at UCLA. The parallel energy of the beam is measured by a two-grid energy analyzer at two axial locations (z = 0.32 m and z = 6.4 m) from the ion gun in LAPD. The calculated ion beam slowing-down time is consistent to within 10% with the prediction of classical Coulomb collision theory using the LAPD plasma parameters measured by a Langmuir probe. To measure cross-field transport, the beam is launched at 15° to the magnetic field. The beam then is focused periodically by the magnetic field to avoid geometrical spreading. The radial beam profile measurements are performed at different axial locations where the ion beam is periodically focused. The measured cross-field transport is in agreement to within 15% with the analytical classical collision theory and the solution to the Fokker–Planck kinetic equation. Collisions with neutrals have a negligible effect on the beam transport measurement but do attenuate the beam current.
Show PACS
52.25.Fi Transport properties
52.70.Ds Electric and magnetic measurements
52.25.Dg Plasma kinetic equations
52.40.Mj Particle beam interactions in plasmas
52.25.Ya Neutrals in plasmas
52.75.-d Plasma devices
52.20.-j Elementary processes in plasmas

Effects of dust-charge fluctuation on the damping of Alfvén waves in dusty plasmas

M. C. de Juli, R. S. Schneider, L. F. Ziebell, and V. Jatenco-Pereira

Phys. Plasmas 12, 052109 (2005); http://dx.doi.org/10.1063/1.1899647 (12 pages) | Cited 9 times

Online Publication Date: 5 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using a completely kinetic description to analyze wave propagation in dusty plasmas, the case of propagation of waves exactly parallel to the external magnetic field and Maxwellian distributions for electrons and ions in the equilibrium is considered. A model for the charging process of dust particles which depends on the frequency of inelastic collisions between dust particles and electrons and ions is used. The dispersion relation and damping rates for Alfvén waves are obtained. For the numerical solutions, the average value of the inelastic collision frequency is used as an approximation. The results show that the presence of dust particles with variable charge in the plasma produces significant additional damping of the Alfvén wave. A novel process of mode coupling of low-frequency waves is demonstrated to occur due to the presence of dust particles.
Show PACS
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.27.Lw Dusty or complex plasmas; plasma crystals
52.40.Db Electromagnetic (nonlaser) radiation interactions with plasma
52.25.Gj Fluctuation and chaos phenomena
52.25.Dg Plasma kinetic equations
52.20.-j Elementary processes in plasmas
52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)

Velocity shear induced transition of magnetohydrodynamic to kinetic Alfvén waves

Yao Chen

Phys. Plasmas 12, 052110 (2005); http://dx.doi.org/10.1063/1.1899664 (7 pages) | Cited 3 times

Online Publication Date: 5 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
It is found that in the linear shear flow after a certain time the noncompressive magnetohydrodynamic Alfvén wave with only k‖ develops large values of k⊥ and becomes the kinetic Alfvén wave with considerable compressibility, and velocity and magnetic field perturbations in the parallel direction (to the background magnetic field). It is found that the perturbation amplitudes of the above kinetic quantities increase continuously with time. The amplitudes are mostly determined by the ratios of the Alfvénic to ion gyrofrequency and of the thermal to magnetic pressure for a specified shear flow.
Show PACS
52.35.-g Waves, oscillations, and instabilities in plasmas and intense beams
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.65.Kj Magnetohydrodynamic and fluid equation

Even harmonics generation of high frequency radiation in current-carrying plasmas

G. Ferrante, M. Zarcone, and S. A. Uryupin

Phys. Plasmas 12, 052111 (2005); http://dx.doi.org/10.1063/1.1901694 (9 pages) | Cited 3 times

Online Publication Date: 5 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Generation of high frequency radiation harmonics in a current-carrying plasma is studied. The physical mechanism responsible for harmonics generation is provided by electron-ion collisions. The current in the plasma is sustained by a constant electric field. It is shown that the electron distribution function anisotropy due to the static field yields generation of even harmonics. As a result, the radiation spectrum emitted by the current-carrying plasma contains both even and odd harmonics, the latter being attributed to currentless plasma. For a broad range of plasma and high frequency radiation parameters, a detailed analysis of the even harmonics properties is reported.
Show PACS
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.38.Dx Laser light absorption in plasmas (collisional, parametric, etc.)

Electromagnetic instability of an axially inhomogeneous plasma

A. I. Smolyakov, S. I. Krasheninnikov, and O. I. Tolstikhin

Phys. Plasmas 12, 052112 (2005); http://dx.doi.org/10.1063/1.1899160 (6 pages) | Cited 2 times

Online Publication Date: 9 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electromagnetic drift instability leading to the excitation of the Alfvén waves in an axially inhomogeneous plasma is investigated. The instability is driven by the axial shear of the E×B drift velocity maintained by the localized density gradient. Analytical dispersion relation has been derived in the short wavelength (WKB) limit. The eigenvalue problem has also been solved numerically by using the recently developed algebraic method [ D. I. Tolstikhin, V. N. Ostrovsky, and H. Nakamura, Phys. Rev. A 58, 2077 (1998) ].
Show PACS
52.35.Qz Microinstabilities (ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron, etc.)
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.25.-b Plasma properties
02.10.Ud Linear algebra

Properties of low and medium frequency modes in two-fluid plasma

Akio Ishida, C. Z. Cheng, and Y-K. M. Peng

Phys. Plasmas 12, 052113 (2005); http://dx.doi.org/10.1063/1.1905604 (9 pages) | Cited 4 times

Online Publication Date: 9 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Based on a two-fluid plasma model where the electron mass and the displacement current are neglected, the eigenmode properties such as the frequency and the compressibility are studied. It is found that these properties strongly depend on the two-fluid parameter kℓi, where k is the wave number of a mode and ℓi is the ion skin depth. Especially it is found that as the two-fluid parameter kℓi increases beyond unity, the Alfvén wave, which is an incompressible mode in the magnetohydrodynamics (MHD) limit, becomes compressible and its phase velocity approaches to the acoustic speed. The slow magnetosonic wave, which is compressible in the MHD limit, becomes incompressible as kℓi increases. Implications of these results are also discussed.
Show PACS
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)

Linear theory for fast collisionless magnetic reconnection in the lower-hybrid frequency range

D. Jovanović and P. K. Shukla

Phys. Plasmas 12, 052114 (2005); http://dx.doi.org/10.1063/1.1900094 (10 pages) | Cited 3 times

Online Publication Date: 10 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A linear theory is presented for the interplay between the fast collisionless magnetic reconnection and the lower-hybrid waves that has been observed in recent computer simulations [ J. F. Drake, M. Swisdak, C. Cattell et al., Science 299, 873 (2003) ]. In plasma configurations with a strong guide field and anisotropic electron temperature, the electron dynamics is described within the framework of standard electron magnetohydrodynamic equations, accounting also for the effects of the electron polarization and ion motions in the presence of perpendicular electric fields. In the linear phase, we find two types of instabilities of a thin current sheet with steep edges, corresponding to its filamentation (or tearing) and bending. Using a surface-wave formalism for the perturbations whose wavelength is larger than the thickness of the current sheet, the corresponding growth rates are calculated as the contributions of singularities in the plasma dispersion function. These are governed by the electron inertia and the linear coupling of the reconnecting magnetic field with local plasma modes propagating in the perpendicular direction that are subject to the Buneman instability. The linear surface wave instability may be particularly important as a secondary instability, dissipating the thin current sheets that develop in the course of the fast reconnection in the shear-Alfvén and kinetic-Alfvén regimes, and providing the anomalous resistivity for the growth of magnetic islands beyond the shear-Alfvén and kinetic-Alfvén scales.
Show PACS
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Vd Magnetic reconnection
94.30.cl Magnetotail
94.30.Lr Magnetic storms, substorms

Effects of Landau quantization on the equations of state in intense laser plasma interactions with strong magnetic fields

Shalom Eliezer, Peter Norreys, José T. Mendonça, and Kate Lancaster

Phys. Plasmas 12, 052115 (2005); http://dx.doi.org/10.1063/1.1914808 (12 pages) | Cited 6 times

Online Publication Date: 10 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Recently, magnetic fields of 0.7(±0.1) gigaGauss (GG) have been observed in the laboratory in laser plasma interactions. From scaling arguments, it appears that a few gigaGauss magnetic fields may be within reach of existing petawatt lasers. In this paper, the equations of state (EOS) are calculated in the presence of these very large magnetic fields. The appropriate domain for electron degeneracy and for Landau quantization is calculated for the density-temperature domain relevant to laser plasma interactions. The conditions for a strong Landau quantization, for a magnetic field in the domain of 1–10 GG, are obtained. The role of this paper is to formulate the EOS in terms of those that can potentially be realized in laboratory plasmas. By doing so, it is intended to alert the experimental laser-plasma physics community to the potential of realizing Landau quantization in the laboratory for the first time since the theory was first formulated.
Show PACS
52.25.Kn Thermodynamics of plasmas
52.38.Dx Laser light absorption in plasmas (collisional, parametric, etc.)

Magnetohydrodynamic shock wave formation: Effect of area and density variation

R. I. Sujith

Phys. Plasmas 12, 052116 (2005); http://dx.doi.org/10.1063/1.1901693 (8 pages)

Online Publication Date: 11 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The nonlinear steepening of finite amplitude magnetohydrodynamic (MHD) waves propagating perpendicular to the magnetic field is investigated. The nonlinear evolution of a planar fast magnetosonic wave in a homentropic flow field is understood well through simple waves. However, in situations where the wave is moving through a variable area duct or when the flow field is nonhomentropic, the concept of simple waves cannot be used. In the present paper, the quasi-one-dimensional MHD equations that include the effect of area variation and density gradients are solved using the wave front expansion technique. The analysis is performed for a perfectly conducting fluid and also for a weakly conducting fluid. Closed form solutions are obtained for the nonlinear evolution of the slope of the wave front in the limits of infinitely large and small conductivity. A general criterion for a compression wave to steepen into a shock is obtained. An analytical expression for the location of shock formation is derived. The effect of area variation and density gradient on shock formation is studied and examples highlighting the same are presented.
Show PACS
52.35.Tc Shock waves and discontinuities
52.35.Bj Magnetohydrodynamic waves (e.g., Alfven waves)
52.35.Dm Sound waves
52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
52.30.Cv Magnetohydrodynamics (including electron magnetohydrodynamics)
52.25.Fi Transport properties

Stability of dust voids

S. V. Vladimirov, V. N. Tsytovich, and G. E. Morfill

Phys. Plasmas 12, 052117 (2005); http://dx.doi.org/10.1063/1.1909201 (14 pages) | Cited 19 times

Online Publication Date: 11 May 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Dust voids are frequently observed as dust-free regions in a dusty plasma. Experiments demonstrate a variety of dust void structures such as stable or unstable voids, global “heatbeat” modes of oscillations of voids, dust voids in the center of the chamber or near its walls. Theory shows that a dust void generally results from the balance of the electrostatic and the plasma (such as the ion drag) forces acting on a dust particle. Here, the stability theory of a void is developed and the void behavior is modeled. It is shown that sequences of stable and unstable void sizes can exist. The dynamics of dust in a plasma follows these stability characteristics leading to various stable and/or unstable dust void structures.
Show PACS
52.27.Lw Dusty or complex plasmas; plasma crystals
52.25.Vy Impurities in plasmas
52.25.Jm Ionization of plasmas
52.35.Tc Shock waves and discontinuities
back to top Nonlinear Phenomena, Turbulence, Transport

Stochastic heating of dust particles with fluctuating charges

U. de Angelis, A. V. Ivlev, G. E. Morfill, and V. N. Tsytovich

Phys. Plasmas 12, 052301 (2005); http://dx.doi.org/10.1063/1.1889446 (4 pages) | Cited 15 times

Online Publication Date: 7 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The results from the kinetic theory of dusty plasmas, which consistently takes into account the charging and Coulomb collisions of plasma particles with dust, are used to show that, due to the dust charge fluctuations in dust-dust interactions, energy is not conserved in the subsystem of dust particles. The growth rate of the dust mean energy is found proportional to the mean square dust charge fluctuations, as physically expected.
Show PACS
52.50.Gj Plasma heating by particle beams
52.27.Lw Dusty or complex plasmas; plasma crystals
52.25.Gj Fluctuation and chaos phenomena
52.25.Dg Plasma kinetic equations
52.20.-j Elementary processes in plasmas
52.35.Qz Microinstabilities (ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron, etc.)
05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion

Fluid description of ion dynamics in a toroidally confined plasma

Abinadab Dieter and R. D. Hazeltine

Phys. Plasmas 12, 052302 (2005); http://dx.doi.org/10.1063/1.1881534 (13 pages) | Cited 2 times

Online Publication Date: 13 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Fluid equations describing ion dynamics in a toroidally confined plasma at low collision frequency are derived. The principle motivation is to present a framework for incorporating basic neoclassical effects into a fluid theory. The ions are assumed to be magnetized in the sense that relevant scale lengths are much longer than the ion gyroradius, and time scales of interest are assumed long compared to the ion bounce time. These assumptions are consistent with, for example, the evolution of unstable magnetic islands, as well as conventional transport. A special case of the present description is the quasistatic, axisymmetric state with nearly uniform pressure and density on flux surfaces. In that case the equations reproduce the radial ion heat transport predicted by neoclassical transport theory. The essential feature of our derivation is its emphasis on heat flow in the direction of the magnetic field.
Show PACS
52.25.Fi Transport properties
52.55.Fa Tokamaks, spherical tokamaks
52.65.Kj Magnetohydrodynamic and fluid equation

Linear coupling of acoustic and cyclotron waves in plasma flows

Andria Rogava and Grigol Gogoberidze

Phys. Plasmas 12, 052303 (2005); http://dx.doi.org/10.1063/1.1886827 (5 pages) | Cited 3 times

Online Publication Date: 13 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
It is found that in magnetized electrostatic plasma flows the velocity shear couples ion-acoustic waves with ion-cyclotron waves and leads, under favorable conditions, to their efficient reciprocal transformations. It is shown that in a two-dimensional setup this coupling has a remarkable feature: it is governed by equations that are mathematically equal to the ones describing coupling of sound waves with internal gravity waves [ Rogava and Mahajan, Phys. Rev. E 55, 1185 (1997) ] in neutral fluids. For flows with low shearing rates a fully analytic, quantitative description of the coupling efficiency, based on a noteworthy quantum-mechanical analogy, is given and transformation coefficients are calculated.
Show PACS
52.30.-q Plasma dynamics and flow
52.35.-g Waves, oscillations, and instabilities in plasmas and intense beams
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
94.20.Bb Wave propagation

Determination of long-range correlations by quiet-time statistics

V. E. Lynch, B. A. Carreras, R. Sanchez, B. LaBombard, B. Ph. van Milligen, and D. E. Newman

Phys. Plasmas 12, 052304 (2005); http://dx.doi.org/10.1063/1.1890985 (6 pages) | Cited 3 times

Online Publication Date: 15 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Quiet-time statistics is an approach to the analysis of fluctuation time series that, by measuring the duration of successive transport events and the quiet times between them, allows the extraction of information on the long-range correlations in the system. It provides information similar to that obtained from rescaled adjusted range (R/S) statistics. However, when the data are contaminated by extraneous oscillations, it is difficult to effectively use R/S statistics or standard quiet-time analysis. In this paper, quiet-time analysis is generalized so that time series contaminated by oscillations can be treated. This new technique is effective over a wide range of time scales.
Show PACS
52.25.Gj Fluctuation and chaos phenomena
52.25.Fi Transport properties
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
05.45.Tp Time series analysis

Harmonics of electromagnetic and electrostatic plasma waves

Peter H. Yoon, Sumin Yi, and Chang-Mo Ryu

Phys. Plasmas 12, 052305 (2005); http://dx.doi.org/10.1063/1.1884129 (9 pages) | Cited 8 times

Online Publication Date: 18 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper shows that there are two types of nonlinear harmonics in a turbulent plasma. Until recently, it was not clear whether the electromagnetic second-harmonic mode [ P. H. Yoon, Phys. Plasmas 2, 537 (1995) ] and the electrostatic harmonic at 2ωpe [ P. H. Yoon, Phys. Plasmas 7, 4858 (2000) ] were separate branches of nonlinear dispersion relation or whether one was a more general solution which includes the other as a special case. This paper shows that the former is true, namely, the two modes are independent solutions. This reconciles previous, apparently contradictory, predictions by showing that electromagnetic harmonic is a long-wavelength mode, while the electrostatic harmonic is characterized by short wavelengths.
Show PACS
52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
52.25.Dg Plasma kinetic equations
52.35.Ra Plasma turbulence
Page 1 of 8 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. Ultracold neutral plasma expansion in two dimensions
  2. Low-frequency flute instabilities of self-pinched ion beams
  3. Stabilization of line tied resistive wall kink modes with rotating walls
  4. Relativistic quasilinear diffusion in axisymmetric magnetic geometry for arbitrary-frequency electromagnetic fluctuations
  5. Pullback transformations in gyrokinetic theory
Go to AIP Home
Copyright © American Institute of Physics
close