Application of diamond to electrode coating of a plasma display panel (PDP) is evaluated, since we expect diamond to emit much secondary electron due to the Auger neutralization induced by Xe ions. In a conventional magnesium oxide-xenon (MgO/Xe) system, the most abundant Xe+ produced in the discharge does not effectively cause the secondary electron emission, because the condition of the Auger neutralization is not satisfied. In order to increase the efficiency of ultraviolet (UV) radiation, being especially important for engineering, we should avoid such inefficiency. Under suitable conditions in diamond/Xe system the Auger neutralization can occur. Further, if the electron affinity chi is negative, i.e., negative electron affinity (NEA), the condition of the Auger neutralization in diamond/Xe system is sufficiently satisfied. First, we calculate the coefficients of the secondary electron emission on diamond of clean surface or of hydrogenated surface where the dangling bonds are terminated, on the basis of the Hagstrum model. If the NEA with the electron affinity chi=-0.5 is realized, the high ion-induced secondary electron coefficients such as gamma(Xe)=0.25 and gamma(Ne)=0.32 are obtained. Next, we carry out a one-dimensional fluid simulation of the electric discharge in which the two secondary electron emission coefficients of Ne and Xe obtained theoretically are set. Results are presented with changing the sustaining voltage, the fraction of Xe, and the duration of the zero-voltage phase. For 10%Xe mixture, it is shown that the efficiency of UV radiation in the diamond coating increases two times higher than that in the MgO coating. An unnecessarily spontaneous breakdown during the zero-voltage phase, which is peculiar to high secondary electron emission materials, is observed. A mechanism of the breakdown is discussed and means to suppress it are proposed. Taking the zero-voltage phase short and increasing the fraction of Xe up to 50%, in comparison with MgO, a maximum improvement of 3.5 times in the efficiency of UV radiation can be performed. The high secondary electron emission due to Xe ion brings about a decrease in the sustaining voltage, and the sustaining voltage can be further lowered by shortening the duration of the zero-voltage phase. The operation with an increase of Xe fraction becomes attainable. The feasibility of the high performance operation on the ac type PDP by utilizing the materials including diamond with high secondary electron emission for Xe is quantitatively shown. (C) 2003 American Institute of Physics.

A charge exchange model is set and its simulation results are compared to those of previous friction model in the lower current branch of a discharge plasma. A remarkable delocalization of a high frequency mode is found in the charge exchange model. When the mean free path of the charge exchange is larger than the system size, the effective temperature is lower than that of the friction model. However, with a decrease of the mean free path, the temperatures of the two models are inverted. Although the bifurcations of the fundamental mode described in previous paper are similarly reproduced, a parameter range has shifted and it is difficult to observe the ponderomotive effect in the charge exchange model. Simulation results are discussed from the view point of the second moments of the distribution function in both velocity and coordinate spaces. It is found that the effects due to the ponderomotive force and previously pointed-out sheath condition are concealed under the diffusion defined by the second moment of the displacement of scattered particles.

Nonlinear phenomena of the ion acoustic wave in a negatively charged plasma-sheath system are observed in the simulation with a convective scheme described by a two-dimensional phase space, and are theoretically analyzed. Subharmonics of a fundamental mode are excited and show the bifurcation phenomena when the intensity of the ion source relating to the ionization is increased. A reversed electric field from the cathode to anode reveals that the ponderomotive force due to a high frequency mode pushes the ions toward the cathode. A nonlinear coupling of two modes through the ponderomotive force is a key idea to construct the model. Nonlinear dynamical model equations involving the coupling of the two modes and an interaction of the sheath with the two modes, i.e., two nonlinear effects, are proposed. The period-doubling bifurcations of the fundamental mode are examined by using the same growth rates with the flow velocity as in our previously published linear theory. (C) 2001 American Institute of Physics.

In a one-dimensional plasma-sheath system representing a concave quasistationary electric potential typical of a negatively charged system, oscillations of ion are simulated by the aid of a convective scheme useful for weakly ionized plasma, and are theoretically investigated. The frequency spectra of the ion current through a cathode reveal to us that two modes of ion acoustic waves are dominant; a high and a low frequency mode. By deriving a linear differential equation with a dissipation and an ion flow, and taking for granted the sheath width and the distribution of ion flow velocity, the dispersion relation for a finite length system can be calculated. The simulation results, such as the reinforcement of the low frequency mode and the suppression of the high frequency mode, are satisfactorily corroborated by the linear theory. The instabilities of the waves are caused by the asymmetry of boundary conditions and by the dissipative effect. (C) 2000 American Institute of Physics. [S1070-664X(00)00603-0].

Ion oscillations in a one dimensional plasma-sheath system are simulated by the aid of the convective scheme, combining the kinetic equation with the Poisson equation. The frequency spectra of the ion current through a cathode reveal to us that two modes of ion acoustic wave are dominant; a high frequency mode and the fundamental mode. By using a linearized differential equation the appearance of the two modes is corroborated. As the nonlinear phenomena on the fundamental mode, excitation of sub-harmonics is observed if the gas pressure concerned with ionization is changed. A model equation of nonlinear oscillation including the ponderomotive force term caused by the high frequency mode is introduced, and sub-harmonics and period-doubling bifurcations are shown by using the growth rate with the flow velocity obtained in our linear theory.

Hysteresis of gas discharge plasma and nonlinear oscillation of low frequency, caused by the trapped ion, are analyzed. Mainly, the hysteresis and emergence of multiple-steady states are discussed by a simple model of chemical-reaction system. It is shown that a function describing the energy balance has three different real roots. The condition for plural roots depends on the ratio of the bulk energy increase to the surface energy loss of plasma. The criterion contains the non-thermodynamic variables such as conductivity and surface quantities. Examination of stabilities of three-obtained solutions by using linear analysis of differential equations manifests that a root represents a saddle point and other two roots represent stable points.

Hysteresis of gas discharge plasma and nonlinear oscillation of low frequency, caused by the trapped ion, are analyzed. Mainly, the hysteresis and emergence of multiple-steady states are discussed by a simple model of chemical-reaction system. It is shown that a function describing the energy balance has three different real roots. The condition for plural roots depends on the ratio of the bulk energy increase to the surface energy loss of plasma. The criterion contains the non-thermodynamic variables such as conductivity and surface quantities. Examination of stabilities of three-obtained solutions by using linear analysis of differential equations manifests that a root represents a saddle point and other two roots represent stable points.

The hysteresis and multiple-steady states of gas discharge plasma are analysed by a simple model of chemical-reaction system. In our analysis the emergence of multiple-steady states is explained by using a fact that a function describing the energy balance has three different real roots. The condition that the function has three roots depends on the ratio of the bulk energy increase to the surface energy loss of plasma. The criterion of taking place of the jump between two steady states is examined in a similar manner to order-disorder transition. The critical parameter contains the non-thermodynamic variables such as conductivity and surface quantities. Stabilities of three obtained solutions are discussed by using linear analysis of differential equations and we find that a root represents a saddle point and other two roots represent stable points. The first step to explain the hysteresis phenomenon in Ar gas discharge plasma is found.

Nonlinear oscillation that indicates chaotic behavior at low frequency in a gas discharge plasma is investigated by analytic and numerical solutions. The electric field in plasma is determined through the Poisson equation by assuming charge distribution: ions distribute spatially uniform, beam electrons from hot cathode are described by an exponentially decreasing distribution, and plasma electrons are in thermal equilibrium and described by the Boltzmann distribution. The electrostatic potential that is obtained analytically by using linear approximation contains the Debye shielding effect. Low frequency motion of the ions in this electric field is calculated numerically. Period-doubling bifurcation and chaotic oscillation are obtained for a region of parameters and they agree with the experimental results qualitatively. © 1994, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.