The nonlinear decay of a circularly polarized wave is reconsidered. We deduce an explicit expression for the growth rate, and present it in a form which is significantly simpler than those of previous papers.

The basic features of dusty plasmas, particularly basic characteristics of dust in a plasma, and typical dusty plasma parameters for different space and laboratory plasma conditions, are presented. The complexity and the diversity of the field of dusty plasma physics are briefly discussed. Theoretical and experimental discoveries of linear and nonlinear features of waves, particularly dust-ion-acoustic and dust-acoustic waves, in dusty plasmas are reviewed.

It is shown that nonlinear self-interaction of energetic particle-driven geodesic acoustic mode does not generate a second harmonic in radial electric field using the fluid model. However, kinetic effects of energetic particles can induce a second harmonic in the radial electric field. A formula for the second-order plasma density perturbation is derived. It is shown that a second harmonic of plasma density perturbation is generated by the convective nonlinearity of both thermal plasma and energetic particles. Near the midplane of a tokamak, the second-order plasma density perturbation (the sum of second harmonic and zero frequency sideband) is negative on the low field side with its size comparable to the main harmonic at low fluctuation level. These analytic predictions are consistent with the recent experimental observation in DIII-D.

The study, being on two-dimensional modelling of low pressure discharges, suggests an approach to the nonlinear inertia term in the momentum equation of the positive ions needed to be accounted for in the free-fall regime of the discharge maintenance. On the basis of conclusions that the inertia term acts in the wall sheath, where the ions fly perpendicularly to the walls, it is shown that (i) the parallel – to the walls – velocity component can be neglected, and (ii) the rest of the convective derivative can be determined by using the energy conservation law in the collisionless case. In a way, the inertia term acting as a retarding force is joined to the momentum loss term by introducing effective collision frequencies. The validity of the procedure is proved in a model of a low pressure argon discharge by comparison with the exact solutions for the two-dimensional spatial distribution of the discharge characteristics (ion velocity, electron density and temperature and DC electric field and its potential). The conclusion is that (i) ignoring the velocity component that is parallel to the walls does not cause deviation from the exact solution, and (ii) the approximation of using the energy conservation law in the collisionless case is good enough.

A neodymium-doped yttrium aluminum garnet laser of wavelength 0.532 μm with the maximum energy of 900 mJ creates plasmas at a focal point in air in the path of a 1 kW continuous wave fiber laser of wavelength 1.08 μm. We find that there is an unexpected influence on a standard set of turbulent parameters in these laser-induced plasmas. Specifically, the continuous wave laser increased the complexity in the turbulent fluctuations. The continuous wave laser reduces the characteristic fluctuation frequencies in the neutral lines. Furthermore, the continuous wave laser enhances turbulence energies in ions while it diminishes turbulence energies in neutrals.

This paper is devoted to the theory of surface waves propagating across axis of symmetry in non-uniform cylindrical metal waveguides with plasma filling. The presented results are devoted to: first, studying an influence of plasma density non-uniformity on the features of these waves; second, studying an influence of an external magnetic fields' non-uniformity on their dispersion properties; third, studying possibility to sustain gas discharge by propagation of these waves under different operating regimes. The problems have been solved both analytically and numerically. Plasma particles are described in the framework of hydrodynamics; fields of the studied waves are determined by a set of Maxwell equations. Analytical research of the obtained equations is carried out by the method of successive approximation; adequacy of such approach is proved here as well. Numerical evaluations of the possibilities to observe experimentally the phenomena, which accompany propagation of these waves, are carried out.

Experiments demonstrate the ~77× amplification of 0.5 to 3.5-ps pulses of seed light by interaction with Langmuir waves in a low density (1.2 × 1019 cm−3) plasma produced by a 1-ns, 230-J, 1054-nm pump beam with 1.2 × 1014 W/cm2 intensity. The waves are strongly damped (kλD = 0.38, Te = 244 eV) and grow over a ~ 1 mm length, similar to what is experienced by scattered light when it interacts with crossing beams as it exits an ignition target. The amplification reduces when the seed intensity increases above ~1 × 1011 W/cm2, indicating that saturation of the plasma waves on the electron kinetic time scale (<0.5 ps) limits the scatter to ~1% of the available pump energy. The observations are in agreement with 2D PIC simulations in this case.

This paper presents an analytical study of the impact of image force on the kinetics of an irradiated complex plasma. The formulation is based on the average charge theory and includes both the number and energy balance of electrons/ions along with the charge neutrality condition. The dependence of reduction in the potential energy surface barrier (and work function) on the number density of dust particles has been investigated and its impact on the charging of dust grains and other physical plasma parameters has been discussed. An interesting conclusion is the fact that the image force consideration leads to larger magnitude of negative charge on the dust particles and the effective work function approaches the value for plane surface with increasing size and number density of dust grains.

When the krypton plasma in a DC glow discharge tube is exposed to an axial magnetic field, the turbulent energy and the characteristic dominant mode in the turbulent fluctuations are systematically and unexpectedly reduced with increasing magnetic field strength. When the index measuring the rate of transfer of energy through fluctuation scales is monitored, a lambda-like dependence on turbulent energy is routinely observed in all magnetic fields. From this, a critical turbulent energy is identified, which also decreases with increasing magnetic field strength.

In dusty plasma, the overlapping Debye spheres around dust grains produce an attractive force. Shadowing force is exerted between neighboring particles because of mutual distortion of ion or neutral flux to the particles. A comparative study has been made on the role of these two forces on 2D structure of dusty system. Radial distribution function for the particles is a comparative study between the effect of the coupled Yukawa-shadowing potential and the coupled Yukawa-Overlapping Debye Sphere (ODS) potential on 2D dust crystal formation, which has been performed by using molecular dynamics simulation. The structure of the system is investigated by calculating the radial distribution function (g(r)) for different values of Γ, κ and dust number densities nd. It is seen from our study that the Coulomb coupling parameter does not have significant effect on both ODS and shadowing forces. The attractive shadowing force is more dominant for grains with large screening parameter. However, the ODS force becomes dominant with the increasing value of the dust number density. The results for the Yukawa-Shadowing and the ODS potential are also compared with experimental results and a close agreement is obtained for attractive shadowing force.

The toroidal precession of circulating particles in tokamaks is studied numerically. The dependence of the precession frequency on the magnetic shear, the elongation of the plasma cross-section, and plasma pressure is investigated. It is concluded that the analytical expressions for the precession frequency by Kolesnichenko et al. (2003 Phys. Plasmas10, 1449–1457) represent a reasonable approximation for the limit cases of tokamaks with circular cross-section and shearless tokamaks with elliptical cross-section. The precession frequency was calculated for non-circular tokamaks with magnetic shear. Based on the numerical results, an interpolation formula for the precession frequency is proposed.