查看更多>>摘要：Plasma Science and Technology (PST) is a journal reporting novel experimental and theoretical results and progress of interdisciplinary and application sciences in the fields related to Plasma Physics. Specific interested areas include: basic plasma phenomena; magnetically confined plasma; inertially confined plasma; astrophysics and space plasma; low temperature plasma; plasma technology; fusion engineering and ion beam bioengineering.
查看更多>>摘要：The longitudinal plasmons are the electrostatic collective excitations of the solid electron gas. In this paper, the dispersion relations of these plasmons for one-, two- and three-dimensional electron gas are compactly derived in two approaches with uniform disturbed Coulomb potentials. The first approach is adopted usually in solid state theory that is the so-called random phase approximation (RPA) with the Lindhard dielectric function in the long-wavelength and high-frequency limits. The second method is a typical plasma fluid description that includes the electron fluid equations with the adiabatic process in the jellium model. The disturbed electrostatic (Coulomb) potential produced by the oscillation of electron density is dimensionally dependent and derived from the Poisson equation in Appendix B.
查看更多>>摘要：Propagation of the surface waves along a two-dimensional plasma column and the far-field radiation patterns are studied in thin column approximation. Wave phase and attenuation coefficients are calculated for various plasma parameters. The radiation patterns are shown. Results show that the radiation patterns are controllable by flexibly changing the plasma length and other parameters in comparison to the metal monopole antenna. It is meaningful and instructional for the optimization of the plasma antenna design.
LI ChengyueDENG BaiquanYAN JianchengG. A. EMMERT...
530-533页
查看更多>>摘要：A new bipartition neutral transport model was developed for quick identification of the recycling properties of the wall-released hydrogenic neutral particles in the vicinity of the divertor target plate. Based on this model, the numerical calculation results are fairly consistent with the results obtained with the 'multi-generation method'. This model can not only be utilized to provide a source term from neutral transport calculations for the B2 edge plasma transport code, which has been used to simulate edge plasma transport of an HL-2A divertor configuration, but can also be specifically applied for fast classification of the divertor plasma as high recycling or low recycling. Our results also show that the transmissivity is lower in the high-recycling regime.
查看更多>>摘要：An electron cyclotron resonance heating (ECRH) system with a maximum output power of 1 MW, a frequency of 68 GHz and a duration of Is was operated on HL-2A tokamak. The temperature profile control and the sawtooth behaviour during ECRH experiments are investigated. 'Density pumpout' during on-axis ECRH is analysed. Features of confinement and electron heat transport during ECRH are studied.
查看更多>>摘要：By using a one-dimensional resistive magnetohydrodynamic (MHD) model, the Riemann problem is solved numerically for the structure of the reconnection layer under a sheared flow along the anti-parallel magnetic field components. The simulation is carried out for general cases with symmetric or asymmetric plasma densities and magnetic fields on the two sides of the initial current sheet, and cases with or without a guide magnetic field, as in various space and fusion plasmas. The generation of MHD discontinuities in the reconnection layer is discussed, including time-dependent intermediate shocks, intermediate shocks, slow shocks, slow expansion waves, and the contact discontinuity. It is shown that the structure of the reconnection layer is significantly affected by the presence of the shear flow. For an initial symmetric current sheet, the symmetry condition is altered due to the shear flow. For cases with an asymmetric initial current sheet, as at the Earth's magnetopause, the strengths of MHD discontinuities change significantly with the shear flow speed. Moreover, the general results for the reconnection layers in the outflow regions on either side of the X line are discussed systematically for the first time.
查看更多>>摘要：Observation has clearly shown that natural space plasmas generally possess a pronounced non-Maxwellian high-energy tail distribution that can be well modeled by a kappa distribution. In this study we investigate the proton cyclotron wave instability driven by the temperature anisotropy (T_⊥/T_‖> 1) of suprathermal protons modeled with a typical kappa distribution in the magnetosheath. It is found that as in the case for a regular bi-Maxwellian, the suprathermal proton temperature anisotropy is subject to the threshold condition of this proton cyclotron instability and the instability threshold condition satisfies a general form T_⊥/T_‖ - 1 = S/β_‖~α, with a very narrow range of the fitting parameters: 0.40 approx< a approx< 0.45, and a relatively sensitive variation 0.27 approx< S approx< 0.65, over 0.01 ≤ β_‖ ≤ 10. Furthermore, the difference in threshold conditions between the kappa distribution and the bi-Maxwellian distribution is found to be small for a relatively strong growth but becomes relatively obvious for a weak wave growth. The results may provide a deeper insight into the physics of this instability threshold for the proton cyclotron waves.
查看更多>>摘要：A kinetic Monte Carlo (kMC) simulation is conducted to study the growth of ultrathin film of Co on Cu(001) surface. The many-body, tight-binding potential model is used in the simulation to represent the interatomic potential. The film morphology of heteroepitaxial Co film on a Cu(001) substrate at the transient and final state conditions with various incident energies is simulated. The Co covered area and the thickness of the film growth of the first two layers are investigated. The simulation results show that the incident energy influences the film growth and structure. There exists a transition energy where the interfacial roughness is minimum. There are some void regions in the film in the final state, because of the influence of the island growth in the first few layers. In addition, there are deviations from ideal layer-by-layer growth at a coverage from 0～2 monolayers (ML).
查看更多>>摘要：The TiO_2 nanoporous film photoelectrode, as a crucial component of dye-sensitized solar cells, has been investigated. The photovoltaic properties and the dark current were studied by two surface modification methods. One was to apply a compact layer between the conductive glass substrate and nanoporous TiO_2 film. Another was to produce TiO_2 nanoparticles among the microstructure by TiCl_4 treatment. A suitable concentration and number of times for TiCl_4 treatment were found in our experiment. The dark current is suppressed by surface modifications, leading to a significant improvement in the solar cells performance. An excessive concentration of TiCl_4 will produce more surface states and introduce a larger dark current reversely. The dye is also regarded as a source of charge recombination in dark to some extent, due to an amount of surface protonations introduced by the interfacial link in the conductive glass substrate/dye interface and dye/TiO_2 interface.
查看更多>>摘要：In this study, the role of the pulse duty ratio was investigated during the deposition of diamond films in a hot filament chemical vapour deposition reactor with a pulsed-dc biased substrate positively relative to the hot filaments. The voltage-current characteristics showed that the discharge current rose with the increase of biasing voltage, which was modified by the duty ratio. Before deposition, two approaches were adopted for the pre-treatment of the silicon substrates, respectively, and the substrates were scratched by diamond paste or seeded by diamond powders using the so-called 'soft dry polished' technique. Diamond films were deposited under a fixed discharge power by changing the duty ratios. In the first group with scratched substrates, it was found that under a high duty ratio the diamond grew slowly with quite poor nucleation, while in the second case a high duty ratio induced a high deposition rate and good diamond quality. Reactive hydrocarbon species with high energy are essential for the initial nucleation process, which is more effectively achieved at a high biasing voltage in the condition of a low duty ratio. In the film growth process, the large discharge current at a high duty ratio represents an increased concentration of electrons and reactive species as well, promoting the growth of diamond films.
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