Shi B.-R.,Southwestern Institute of Physics
Chinese Physics B | Year: 2014
An analytical expression of the peeling mode in the near separatrix region of diverted tokamak plasma is derived. It is shown that in diverted plasmas both with single and double X points, though the perturbed potential energy of the unstable peeling mode tends to be large, its growth rate becomes very small due to the even larger kinetic energy. Compared to some recent studies that give qualitatively correct results about this growth rate, our result is directly related with the diverted equilibrium quantities suitable for application to realistic experiments. © 2014 Chinese Physical Society and IOP Publishing Ltd.
Luo T.,Southwestern Institute of Physics
Journal of Nuclear Materials | Year: 2011
Li4SiO4 will be applied as tritium breeding materials in future fusion reactor. The release behavior of tritium from neutron-irradiated Li4SiO4 should be sensitive to the chemical states of lithium, oxygen and silicon on the surface of Li 4SiO4 with irradiated defects. The present study is focused on the influence of hydrogen isotopes and irradiation defects on surface chemical state of Li4SiO4. The X-ray Photoelectron Spectroscopy (XPS) was compared between non-irradiated Li4SiO 4 and D2 +-irradiated one. It was observed by that the binding energy (BE) of electron for Li-1s, O-1s and Si-2p of non-irradiated Li4SiO4 were 60.9 eV, 536.1 eV and 107.1 eV respectively. However new XPS peak for Li-1s at 57.2 eV, three XPS peaks for O-1s (at 536.1 eV, 533.2 eV and 531.3 eV, respectively) and three XPS peaks for Si-2p (at 107.1 eV, 104.2 eV and 99.7 eV, respectively) were observed in D 2 +-irradiated Li4SiO4. It is considered that the XPS peaks of 531.3 eV and 104.2 eV should be corresponding to O-1s and Si-2p in -Si-O-D while the XPS peak of 533.2 eV should be corresponding to O-1s in D-O-D. The formation of -Si-O-D and D-O-D is considered to be due to typical irradiated defects (lithium vacancy, silicon vacancy and implanted deuterium) induced by D2 +-irradiation. © 2010 Elsevier B.V. All rights reserved.
Qu H.,Southwestern Institute of Physics
Plasma Science and Technology | Year: 2013
A simple and direct theoretical method has been proposed to investigate the so- called ion-banana-orbit-width (IBW) effect on the bootstrap current in the region of magnetic islands generated by the neoclassical tearing mode (NTM). The result shows that, when the IBW approaches the island width, the (ion) bootstrap current can be partly restored inside the island while the pressure profile is flattened. This can lead to the reduction of the bootstrap current drive on the NTM. The strength of the IBW effect on the NTM is related to the safety factor and the inverse aspect ratio on the rational surface.
Shi B.,Southwestern Institute of Physics
Plasma Physics and Controlled Fusion | Year: 2010
The tokamak pedestal density structure is generally studied using a diffusiondominant model. Recent investigations (Stacey and Groebner 2009 Phys. Plasmas 16 102504) from first principle based physics have shown a plausible existence of large inward convection in the pedestal region. The diffusion- convection equation with rapidly varying convection and diffusion coefficients in the near edge region and model puffing-recycling neutral particles is studied in this paper. A peculiar property of its solution for the existence of the large convection case is that the pedestal width of the density profile, qualitatively different from the diffusion-dominant case, depends mainly on the width of the inward convection and only weakly on the neutral penetration length and its injection position. © 2010 IOP Publishing Ltd.
Guo B.,Wuhan University of Technology |
Qiu X.-M.,Southwestern Institute of Physics
Journal of Electromagnetic Waves and Applications | Year: 2011
In the present paper, we first show that the plasma injected into the interaction region forms a periodical distribution of the plasma density that is called self-induced density grating and exerts a periodic perturbation on the dielectric constant under two strong counterpropagating waves modulation. In succession, we demonstrate that the self-induced quasi periodic plasma density grating formed by the self-induced distributed feedback possesses the properties of plasma photonic crystal (PPC). Therefore, the formation of PPC by the self-induced quasi periodic plasma density grating is a feasible fabrication scenario for PPC. Based on an equivalent model of the plasma density grating, a dispersion relation is derived, and a simple case is calculated and discussed. © 2011 VSP.