[en] A new-type of lower hybrid wave (LHW) launcher which can work as active and passive waveguide array alternately is described. Its physical model and calculation method are given. The power spectrum and the reflection properties of the launcher are studied. For the mean reflection coefficients of the active waveguide, and the directivity coefficients of the transmitted power spectrum and their dependences on the plasma parameters and the launcher parameters are calculated. More precise analyses of the properties of the LHCD launcher on the HL-1M tokamak are given

[en] The experimental study results on properties of the non-equilibrium plasma produced by silent discharge are presented. The experimental results of ozone synthesis in both oxygen and air plasma are given in detail. When oxygen is used as the discharge gas, the mass concentration of ozone C is 18.9 mg·L^-1 and the production rate Q is 1800 mg·h^-1, the specific energy yield η is 70 g·(kW·h)^-1. The mass concentration of ozone rises with the increase of voltage applying on the electrodes and reduces with the increase of the gas flow rate. The properties of the dielectric material and its thickness will strongly influence the performance of the ozone generator. The experimental results show that ozone can be used in the disposal of pulp waste liquor because of its strong oxidizing ability

[en] Recent experimental and theoretical studies of two-dimensional (2D) turbulence reveal that spectrally condensed turbulence which is a system of coupled large-scale coherent flow and broadband turbulence, is similar to plasma turbulence near the L-H transition threshold. Large condensate vortices fed via the turbulent inverse energy cascade, can control both the level of the broadband turbulence by shear decorrelation, and the energy injected into turbulence at the forcing scale via sweeping of the forcing-scale vortices. The interaction between these ingredients of spectrally condensed fluid turbulence is in many aspects similar to the interactions in the zonal flow-GAMs-turbulence system in plasma. In this paper we overview recent results on condensed 2D turbulence and present evidence of interaction between its three components: condensate structures, turbulence and forcing-scale vortices. This is compared with the modifications in the spectra of plasma electrostatic potential during L-H transitions. It is shown that mean zonal flows are spatially and temporally correlated with both the broadband turbulence and with the narrow spectral range identified as the spectral range of the underlying instability. (author)

[en] An overview of recent results related to the physics of turbulent structure generation and their interactions in the H-1 heliac is presented. In particular, the role of zonal flows, or time-varying shear radial electric fields, in anomalous transport and confinement transitions is investigated. It is shown that large-scale coherent structures, including zonal flows, are generated through an inverse energy cascade from the unstable spectral range. Once developed, zonal flows affect other turbulent structures and reduce the particle transport driven by them. The phase randomization of coherent structures by zonal flows is shown to be responsible for reducing the anomalous transport. Zonal flows are also shown to act as precursors during spontaneous low-to-high transitions in H-1

No abstract available

[en] The lower hybrid current drive (LHCD) system on the HL-1M tokamak has been improved significantly in the past year. In order to carry out LHCD experiments with higher RF power, the operation mode with two klystrons in parallel was realized. Several problems were solved in the operation mode that involved frequency, balance of power and phase control. Up to now, the achieved system parameters are as follows: maximum output power of 850 kW, longest operation duration of 1050 ms, the launcher coupling efficiency of 85%

[en] An ECRH system with 500 kW/50 ms in the 75 GHz range has been built on the HL-1M tokamak. Top-injection and horizontal-injection antennas have been designed, and quasi-optical transmission developed. During adjustment, optimal experiment conditions and parameters of the ECRH system are obtained. Wave injections with O-mode or X-mode have been performed on the high or low field side. In the HL-1M ECRH experiments, the electron temperature measured with ECE diagnostics increases more than 40%, and negative shear distribution of the plasma current is obtained and the phenomenon of internal fish-bone mode instability has been observed with soft X-ray apparatus

[en] Several microstructural parameters can be obtained from the HWHM (half width at half maximum) Γ of the TO-like mode and the peak positions in the Raman spectra of non-crystalline silicon materials (including multilayer and single thick films). These are the rms bond angle variation Δθ=(Γ-7.5)/3 (deg), the average distortion energy per bond (u) of the inteface, and the stress near the interface (σ), in a-Si:H layers. The grain size of the μc-Si films can be also obtained from Δd ∝ 2π(B/Δω_TO)^1/2. The distortion energy, is given by U=3K(ranti Δ anti θ)², where K and r are the force constant of Si (9.2x10³ dyn/cm²) and the bond length of Si (2.4x10^-8 cm), respectively, σ is equal to n x ΔU, n is the total number of distorted Si-Si bonds per unit area near the interface, and ΔU is the average excess distortion energy. The microstructural parameters of thick single μc-Si:B films and different composition-modulated superlattices are compared when the following quantities are changed: (1) d_s (thickness of the a-Si:H layer), (2) R (the NH₃/SiH₄ ratio). The microstructures can well be understood after proper theoretical models are adopted, i.e., using the Peierls-Nabarro model, it can be explained that the stress near the interface is inversely proportional to the thickness of the a-Si:H layer (d_s) within the range of a few monolayers. The Pantelides model can be used to explain the overcoordination of nitrogen in the a-Si:H layer near the interface. (orig.)

[en] Highlights: • Thermal-induced enhancement degree of Ho³⁺ decreases with increasing Ho³⁺ doping content. • High Yb³⁺ content benefit the population of the defect energy level. • High Yb³⁺ content also induce back energy transfer from Ho³⁺ to Yb³⁺ions. • The enhancement degree is further increased by constructing core-shell structure. It was reported that the UC emission intensity can be improved by introducing a thermal field and this phenomenon is highly related to the Yb³⁺ ions. Herein, we verify the thermal-induced UC enhancement degree can be further increased by separating the Yb³⁺ ions in the core and shell to promote the population of the defect energy level and inhibit the back energy transfer from Ho³⁺ to Yb³⁺ ions.

[en] We report on a new high frequency excitation, identified as a longitudinal guided mode, supported in a hard isotropic film deposited on a substrate. The observation of this mode allows for a direct determination of the C₁₁ elastic constant of the film. The remaining constant, C₄₄, was determined through a least square fit to the dispersion of the pseudo surface wave. Properties of the observed excitations were investigated by evaluating their mode density and polarization characteristics