M. Y. Yu

Power transfer and mode transitions in low-frequency inductively coupled plasmas

Operation and mode jumps in low-frequency (500 kHz) radio-frequency inductively coupled plasmas are investigated. The discharge is driven by a flat inductive coil which can excite the electrostatic (E) and electromagnetic (H) discharge modes. The power transfer efficiency and mode transition behavior are studied. It is found that the power reflection coefficient as a function of the input power is minimal in the vicinity of the mode transitions and exhibits hysteresis, which is also observed when the operating gas pressure is varied.

Self‐consistent theory of ion acoustic waves in a dusty plasma

From a self‐consistent theory for dust‐charging, the linear dispersion relation for ion acoustic waves is derived. It is shown that the waves are damped because of energy exchange with the dust‐charging process.

Electrostatic sheath at the boundary of a dusty plasma

The effect of massive charged dust grains on plasma–wall interaction is investigated using the electrostatic probe model for the dust charging process. It is shown that the dust grains can have a substantial effect on the behavior of the electrostatic potential and particle densities near the wall.

On the realization of the current-driven dust ion-acoustic instability

The current-driven dust ion-acoustic instability in a collisional dusty plasma is studied. The effects of dust-charge variation, electron and ion capture by the dust grains, as well as various dissipative mechanisms leading to the changes of the particles momenta, are taken into account. It is shown that the threshold for the excitation of the dust ion-acoustic waves can be high because of the large dissipation rate induced by the dusts.

Shielding of a slow test charge in a collisional plasma

The potential of a slowly moving test charge is considered. Collisional effects are described by a simple BGK model as well as a Lorentz model. It is found that the far‐field potential may fall off as the inverse square of distance when the collision frequency is larger than the plasma frequency.

Standing surface waves in a dust-contaminated large-area planar plasma source

The effect of charged particulates or dusts on surface wave produced microwave discharges is studied. The frequencies of the standing electromagnetic eigenmodes of large-area flat plasmas are calculated. The dusts absorb a significant amount of the plasma electrons and can lead to a modification of the electromagnetic field structure in the discharge by shifting the originally excited operating mode out of resonance. For certain given proportions of dusts, mode conversion is found to be possible. The power loss in the discharge is also increased because of dust-specific dissipations, leading to a decrease of the operating mode quality factor.

Recent advances in the theory of nonlinear surface waves

Abstract Recent advances associated with an improvement of the popular cold-plasma sharp-boundary model in the theory of nonlinear surface waves in low-temperature plasmas are reviewed. The revised boundary model calls for the existence of induced nonlinear surface charges and currents in an infinitely thin (spatially singular) layer at the plasma boundary. It provides a much more accurate description of the physics of the region, especially with respect to the nonlinear effects. Various nonlinear wave phenomena of current interest, such as those of the third-order ponderomotive effect, nonlinear waves, and soliton formation, are discussed. It is demonstrated that for the problems considered, the results from the new model agree well with those obtained from the kinetic theory. The latter inherently includes a more complete description of the boundary conditions since the plasma density can vanish smoothly (and physically consistently) within a boundary layer adjacent to the wall. The layer, or sheath region, has a small but finite dimension usually of the order of the Debye length. Effectively, the new model takes into account the relevant physical processes occuring in this layer, which itself is nevertheless taken to be of zero width. Thus, spatially singular charges and currents appear in the model. Furthermore, a new class of nonlinear cold-plasma surface wave solutions is also reviewed. These solutions are obtained by separating the temporal and spatial dependences of the physical quantities. They are mathematically exact in the sense that starting from the basic cold-plasma equations and boundary conditions, no approximation of any kind needs to be made in obtaining them. Exact nonlinear surface wave solutions in cylindrically and spherically bounded plasmas, as well as the effects of constant and oscillatory external electric fields in the dielectric container, are presented. Modern applications of the results from the above topics in various branches of physics, chemistry, and technology are discussed.

Nanopowder management and control of plasma parameters in electronegative SiH4 plasmas

The nanopowder management and control of plasma parameters in electronegative SiH4 plasmas were discussed. The spatial profiles of electron and positive/negative ion number densities, electron temperature and charge of the fine particles were obtained. It was found that management of powder charge distribution is also possible through control of the external parameters.

EXACT ION ACOUSTIC SOLITARY WAVES IN AN IMPURITY-CONTAINING MAGNETIZED PLASMA

Fully nonlinear ion acoustic solitary waves propagating obliquely to the external magnetic field in an impurity‐containing magnetized plasma are investigated.

Nonlinear wave evolution in bounded plasmas

The evolution equations governing large amplitude waves in cold plasma columns bounded by deformable dielectrics are presented and discussed.