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May 2001

Volume 8, Issue 5, pp. 1447-2594

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back to top Basic Plasma Phenomena, Waves, Instabilities

The radial structure of a plasma column sustained by a surface wave

N. A. Azarenkov, I. B. Denysenko, A. V. Gapon, and T. W. Johnston

Phys. Plasmas 8, 1467 (2001); http://dx.doi.org/10.1063/1.1358310 (15 pages) | Cited 14 times

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The self-consistent radial profiles are obtained for a steady-state, surface-wave-sustained, unmagnetized argon plasma in a cylindrical dielectric tube surrounded by a conductor. The density profiles obtained using the correct constant mean-free-path ion–neutral collision differ considerably from those obtained using the common (but here quite incorrect) approximation of constant mean free time, but are little affected by changes in the profile of wave energy deposition. Various profiles for some typical cases are also compared for three different electron heat transport assumptions. These electron heat transport coefficients are as follows: (i) The correct value, (ii) 102× the correct value, to obtain the essentially isothermal case, and (iii) 10−2× the correct value, to approximate negligible heat transport (the adiabatic case). From the comparison of the temperature profiles, it became clear that the best electron heat transport simplification is to take the electrons to be isothermal [i.e., assumption (ii)], in which case only the total absorption per unit length is important, and not the details of the surface wave behavior. © 2001 American Institute of Physics.
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52.80.-s Electric discharges
52.35.-g Waves, oscillations, and instabilities in plasmas and intense beams
52.25.Fi Transport properties
52.20.Hv Atomic, molecular, ion, and heavy-particle collisions

Linear wave dispersion laws in unmagnetized relativistic plasma: Analytical and numerical results

Jan Bergman and Bengt Eliasson

Phys. Plasmas 8, 1482 (2001); http://dx.doi.org/10.1063/1.1358313 (11 pages) | Cited 22 times

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In this paper dispersion laws for electrostatic and electromagnetic waves in a homogeneous and unmagnetized relativistic Vlasov plasma are derived. From the dispersion laws the relativistic plasma frequency, which is temperature dependent is derived. Using the standard technique of successive approximations, simple but powerful approximate relativistic dispersion laws are derived, resembling the electromagnetic dispersion law and the electrostatic Bohm–Gross dispersion law in the nonrelativistic case. The relation between the relativistic plasma frequency ωpe, Debye wave number kD and the thermal velocity vth,e is established. The approximate dispersion laws are compared with numerical solutions of the full dispersion laws. The full dispersion equations are transformed so that they are well suited for numerical evaluation in the temperature range where a fully relativistic treatment is needed. © 2001 American Institute of Physics.
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52.27.Ny Relativistic plasmas

Dusty plasma expansion with a variable charge in a spherical configuration

M. Djebli, R. Annou, and T. H. Zerguini

Phys. Plasmas 8, 1493 (2001); http://dx.doi.org/10.1063/1.1358890 (4 pages) | Cited 6 times

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The expansion of a dusty plasma into a vacuum with a variable charge is considered self-consistently. Due to the plasma spatial finitude, loss terms are introduced in fluid equations. Particles attachment also imposes that the Boltzmann distribution be relaxed. A nonlinear differential equations system is obtained and solved numerically. A breakdown of the quasineutrality on the front along with a buildup of scale-invariant waves are reported as well. © 2001 American Institute of Physics.
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52.27.Lw Dusty or complex plasmas; plasma crystals
52.27.Jt Nonneutral plasmas

Evolution of perturbation in charge-varying dusty plasmas

S. I. Popel, A. P. Golub’, T. V. Losseva, R. Bingham, and S. Benkadda

Phys. Plasmas 8, 1497 (2001); http://dx.doi.org/10.1063/1.1359743 (8 pages) | Cited 14 times

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The nonstationary problem of the evolution of perturbation and its transformation into nonlinear wave structure in dusty plasmas is considered. For this purpose two one-dimensional models based on a set of fluid equations, Poisson’s equation, and a charging equation for dust are developed. The first (simplified) model corresponds to the case [Popel et al., Phys. Plasmas 3, 4313 (1996)] when exact steady-state shock wave solutions can exist. This simplified model includes variable-charged dust grains, Boltzmann electrons, and inertial ions. The second (ionization source) model takes into account the variation of the ion density and the ion momentum dissipation due to dust particle charging as well as the source of plasma particles due to ionization process. The computational method for solving the set of equations which describe the evolution in time of a nonlinear structure in a charge-varying dusty plasma is developed. The case of the evolution of an intensive initial nonmoving region with a constant enhanced ion density is investigated on the basis of these two models. The consideration within the ionization source model is performed for the data of the laboratory experiment [Luo et al., Phys. Plasmas 6, 3455 (1999)]. It is shown that the ionization source model allows one to obtain shock structures as a result of evolution of an initial perturbation and to explain the experimental value of the width of the shock wave front. Comparison of the numerical data obtained on the basis of the ionization source model and the simplified model shows that the main characteristic features of the shock structure are the same for both models. Nevertheless, the ionization source model is much more sensitive to the form of the initial perturbation than the simplified model. The solution of the problem of the evolution of perturbation and its transformation into shock wave in charge-varying dusty plasmas opens up possibilities for description of the real phenomena like supernova explosions as well as of the laboratory and active space and geophysical experiments. © 2001 American Institute of Physics.
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52.35.Tc Shock waves and discontinuities
52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)
52.25.Vy Impurities in plasmas
52.35.Dm Sound waves

Fluid and kinetic stability of virtual cathodes for the periodically oscillating plasma sphere

R. A. Nebel and J. M. Finn

Phys. Plasmas 8, 1505 (2001); http://dx.doi.org/10.1063/1.1363664 (9 pages) | Cited 7 times

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Recent theoretical work [R. A. Nebel and D. C. Barnes, Fusion Technol. 38, 28 (1998); D. C. Barnes and R. A. Nebel, Phys. Plasmas 5, 2498 (1998)] has suggested that a tiny oscillating ion cloud (referred to as the periodically oscillating plasma sphere or POPS) may undergo a self-similar collapse that can result in the periodic and simultaneous attainment of ultrahigh densities and temperatures. However, a major uncertainty in this plasma system is the behavior of the electron cloud that forms a virtual cathode. Here it is demonstrated that the required electron cloud (which forms a harmonic oscillator potential) is susceptible to an instability related to buoyancy-driven modes present in compressible fluids. Although it is demonstrated that no absolutely stable profiles with uniform electron density exist, stable profiles that are close to the required harmonic oscillator potential are found. A simple two-stream analysis indicates that kinetic effects lead to a critical limit in λD/a above which the virtual cathodes are stable. This result is consistent with previous experimental observations. © 2001 American Institute of Physics.
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52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Qz Microinstabilities (ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron, etc.)
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)

Nonlocal theory of drift type waves in a collisional dusty plasma

M. Chakraborty, S. Sen, and A. Fukuyama

Phys. Plasmas 8, 1514 (2001); http://dx.doi.org/10.1063/1.1329652 (4 pages)

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A nonlocal theory of low-frequency drift-type waves has been developed in a magnetized collisional dusty plasma in a sheared slab geometry. It is shown that the well-known stability of the drift waves in a sheared slab geometry does not hold in the presence of dust particles and a new unstable mode exists for typical laboratory plasma parameters. © 2001 American Institute of Physics.
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52.27.Lw Dusty or complex plasmas; plasma crystals
52.20.-j Elementary processes in plasmas
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Kt Drift waves
52.25.-b Plasma properties

Modeling of discharges generated by electron beams in dense gases: Fountain and thunderstorm regimes

S. O. Macheret, M. N. Shneider, and R. B. Miles

Phys. Plasmas 8, 1518 (2001); http://dx.doi.org/10.1063/1.1363666 (11 pages) | Cited 5 times

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In this paper we present an analysis of the predicted dynamics of plasmas generated in air and other gases by injecting beams of high-energy electrons. Two distinct regimes are found, differing in the way that the excess negative charge brought in by the ionizing electron beam is removed. In the first regime, called a fountain, the charge is removed by the back current of plasma electrons toward the injection foil. In the second, called a thunderstorm, a substantial cloud of negative charge accumulates, and the increased electric field near the cloud causes a streamer to strike between the cloud and a positive or grounded electrode, or between two clouds created by two different beams. A quantitative analysis, including electron beam propagation, electrodynamics, charge particle kinetics, and a simplified heat balance, is performed in a one-dimensional approximation. © 2001 American Institute of Physics.
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52.80.-s Electric discharges
52.50.Dg Plasma sources
52.65.-y Plasma simulation
41.75.Fr Electron and positron beams

Nonlinear electrostatic waves in a magnetized dust-ion plasma

T. Farid, A. A. Mamun, P. K. Shukla, and Arshad M. Mirza

Phys. Plasmas 8, 1529 (2001); http://dx.doi.org/10.1063/1.1364512 (4 pages) | Cited 21 times

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It is shown that the nonlinear equation governing the dynamics of coupled dust-acoustic and dust-cyclotron waves in a magnetized dust-ion plasma can be written in the form of an energy integral. The latter is analyzed analytically as well as numerically to investigate the properties of arbitrary amplitude solitary waves. It is found both analytically as well as numerically that there exist solitary waves only with a negative potential. The implications of these results to some space and astrophysical dusty plasma systems, especially to planetary ring systems and cometary tails, are briefly discussed. © 2001 American Institute of Physics.
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52.27.Lw Dusty or complex plasmas; plasma crystals
52.25.Vy Impurities in plasmas
52.35.Sb Solitons; BGK modes
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Structure and melting of two-dimensional dust crystals

Hiroo Totsuji

Phys. Plasmas 8, 1856 (2001); http://dx.doi.org/10.1063/1.1343884 (7 pages) | Cited 21 times

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Dust particles in plasmas confined near the boundary between the plasma bulk and the sheath form a two-dimensional system when appropriate conditions are satisfied. To keep dust particles from running away horizontally, the electrostatic potential is usually applied to the electrode surrounding these dusty plasmas and we have finite two-dimensional systems of dust particles. Adopting the Yukawa model for the interaction between dust particles, structures of finite two-dimensional Yukawa systems at low temperatures have been analyzed both by molecular dynamics simulations and variational methods. The effect of the correlation energy between dust particles is shown to play an important role in the formation of the one-body distribution in these systems. Molecular dynamics simulations of large systems typically with 103 to 104 particles have been performed and the behavior of the mean square displacement is obtained for various combinations of characteristic parameters. The results are discussed in relation to the melting transition on the basis of the theoretical analysis on static structures. © 2001 American Institute of Physics.
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52.27.Lw Dusty or complex plasmas; plasma crystals
02.70.Ns Molecular dynamics and particle methods
52.40.Kh Plasma sheaths
02.30.Xx Calculus of variations

Neoclassical effects in the annular Penning trap

Scott Robertson, Joe Espejo, John Kline, Qudsia Quraishi, Matt Triplett, and Bob Walch

Phys. Plasmas 8, 1863 (2001); http://dx.doi.org/10.1063/1.1345885 (7 pages) | Cited 2 times

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Neoclassical transport has been investigated with a modified Malmberg–Penning trap which has conductors along the axis to create an azimuthal magnetic field. The axial bounce motion of the electrons is accompanied by a radial drift which changes sign at the ends of the device causing drift orbits of finite radial extent. Analysis and numerical simulations show that the transport is neoclassical with mobility and diffusion coefficients depending upon the axial magnetic field alone rather than the absolute value of the magnetic field. Experiments with added helium gas to create electron-neutral collisions show that the electron mobility from an applied radial electric field and the Ware drift from an azimuthal electric field both have neoclassical values over a wide range of magnetic fields and collision frequencies. © 2001 American Institute of Physics.
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52.27.Jt Nonneutral plasmas
52.55.Dy General theory and basic studies of plasma lifetime, particle and heat loss, energy balance, field structure, etc.
52.25.Fi Transport properties

Collective modes in a strongly coupled dusty plasma

P. K. Kaw

Phys. Plasmas 8, 1870 (2001); http://dx.doi.org/10.1063/1.1348335 (9 pages) | Cited 22 times

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It is widely recognized that in a typical dusty plasma encountered in the laboratory or outer space, the dust component is in a strongly coupled state because the interaction energy of neighboring dust particles due to shielded Coulomb (“Yukawa”) forces is much larger than their thermal energy. Low frequency collective modes involving the motion of dust particles are therefore greatly influenced by the strong correlation effects in the dust component. In this paper a dispersion relation for low-frequency collective modes using a generalized hydrodynamics model for the dust component has been derived. Strong correlation effects are described in terms of viscoelastic transport coefficients and a finite relaxation time for the memory kernel. Novel collective effects such as new corrections to dispersion terms for longitudinal dust acoustic waves and the existence of transverse shear waves supported by strong correlations have been identified. New physical processes involving nonuniform charge number equilibria and delayed charging effects which could drive the shear wave instability have also been studied. A report on some new experiments where self-excited transverse shear modes are seen when the dust component of the plasma is in a strongly correlated fluid-like state is also presented. © 2001 American Institute of Physics.
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52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Qz Microinstabilities (ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron, etc.)
52.27.Lw Dusty or complex plasmas; plasma crystals
52.35.-g Waves, oscillations, and instabilities in plasmas and intense beams
52.25.Fi Transport properties

Radial compression and inward transport of positron plasmas using a rotating electric field

R. G. Greaves and C. M. Surko

Phys. Plasmas 8, 1879 (2001); http://dx.doi.org/10.1063/1.1350570 (7 pages) | Cited 14 times

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It has recently been demonstrated that positron plasmas confined in a Penning-Malmberg trap can be compressed radially by applying a rotating electric field [Phys. Rev. Lett. 85, 1883 (2000)]. A more complete description of the original experiments is presented, together with the results of new measurements. Good coupling of the rotating electric field is observed over a broad range of frequencies. The heating caused by the rotating field is counteracted by cooling using a polyatomic gas. Rapid compression rates math/n ∼ 15 s−1 can be achieved, with central density increases of a factor of 20 or more. The good coupling and high compression rates can be explained in terms of excitation of heavily damped Trivelpiece–Gould modes, or alternatively as coupling directly to particle bounce resonances. Potential improvements and applications are discussed, including the production of high-density positron plasmas and brightness-enhanced positron beams. © 2001 American Institute of Physics.
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52.27.Jt Nonneutral plasmas
41.75.Fr Electron and positron beams
34.80.Uv Positron scattering

Dynamic behaviors of dust particles in the plasma–sheath boundary

S. Takamura, T. Misawa, N. Ohno, S. Nunomura, M. Sawai, K. Asano, and P. K. Kaw

Phys. Plasmas 8, 1886 (2001); http://dx.doi.org/10.1063/1.1350967 (7 pages) | Cited 25 times

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A variety of dynamic behaviors in dusty plasmas is expected under the experimental condition of weak friction with gas molecules. The device “KAGEROU” provides such an environment for dynamic collective phenomena. Self-excited dust oscillations in Coulomb crystals have been observed at low values of plasma density and gas pressure. An instability mechanism was identified to be delayed charging in an inhomogeneous equilibrium dust charge in the sheath. The theoretical growth rate was formulated in relation to the destabilization of a transverse dust lattice wave (T-DLW), which was found to be very sensitive to the presence of a small amount of hot electrons which produces a substantial positive equilibrium charge gradient ∇Qd-eq around the equilibrium position of dust particles in the plasma–sheath boundary. The first experimental observation of a correlated self-excited vertical oscillations in a one-dimensional dust chain indicates a destabilization of T-DLW. The experimental condition is very consistent with the parameter area which predicts numerically an instability of T-DLW. © 2001 American Institute of Physics.
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52.27.Lw Dusty or complex plasmas; plasma crystals
52.40.Hf Plasma-material interactions; boundary layer effects
52.40.Kh Plasma sheaths
52.25.Vy Impurities in plasmas
52.35.Fp Electrostatic waves and oscillations (e.g., ion-acoustic waves)
52.25.-b Plasma properties
52.35.Py Macroinstabilities (hydromagnetic, e.g., kink, fire-hose, mirror, ballooning, tearing, trapped-particle, flute, Rayleigh-Taylor, etc.)
52.35.Qz Microinstabilities (ion-acoustic, two-stream, loss-cone, beam-plasma, drift, ion- or electron-cyclotron, etc.)

Statistical theory of dusty plasmas: Microscopic description and numerical simulations

A. G. Zagorodny, A. G. Sitenko, O. V. Bystrenko, P. P. J. M. Schram, and S. A. Trigger

Phys. Plasmas 8, 1893 (2001); http://dx.doi.org/10.1063/1.1357436 (10 pages) | Cited 5 times

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The first principles of statistical mechanics are used to formulate the basic points of kinetic theory of dusty plasmas. Equations for microscopic phase densities of plasma particles and grains are derived with regard for electron and ion collection by dust particles and elastic contact collisions between grains. The Bogolyubov–Born–Green–Kirkwood–Yvon hierarchy is generalized to the case of dusty plasmas and used to derive kinetic equations, taking into account elastic and inelastic particle collisions. An example of such an equation is presented and applied to the calculations of stationary grain velocity and charge grain distributions. The results of Monte Carlo studies of a strongly coupled dusty plasma are also presented. Microscopic simulations of critical behavior of a dusty plasma with regard for the discrete nature of the plasma subsystem are performed. The effect of nonlinear screening of dust particles on the dusty crystal formation is considered as well. © 2001 American Institute of Physics.
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52.27.Lw Dusty or complex plasmas; plasma crystals
52.25.Dg Plasma kinetic equations
52.65.Pp Monte Carlo methods
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