Engineering topics

Yiping, Chen

Publications and source records attributed to Yiping, Chen.

3 records

DOE OSTI2013

Modelling of radiative divertor operation towards detachment in experimental advanced superconducting tokamak

In order to actively control power load on the divertor target plates and study the effect of radiative divertor on plasma parameters in divertor plasmas and heat fluxes to the targets, dedicated experiments with Ar impurity seeding have been performed on experimental advanced superconducting tokamak in typical L-mode discharge with single null divertor configuration, ohmic heating power of 0.5 MW, and lower hybrid wave heating power of 1.0 MW. Ar is puffed into the divertor plasma at the outer target plate near the separatrix strike point with the puffing rate 1.26 Multiplication-Sign 10{sup 20} s{sup -1}. The radiative divertor is formed during the Ar puffing. The SOL/divertor plasma in the L-mode discharge with radiative divertor has been modelled by using SOLPS5.2 code package [V. Rozhansky et al., Nucl. Fusion 49, 025007 (2009)]. The modelling shows the cooling of the divertor plasma due to Ar seeding and is compared with the experimental measurement. The changes of peak electron temperature and heat fluxes at the targets with the shot time from the modelling results are similar to the experimental measurement before and during the Ar impurity seeding, but there is a major difference in time scales when Ar affects the plasma in between experiment and modelling.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2012

Hydrothermal syntheses, structures and characterizations of two luminescent cadmium(II) complexes with p-xylenediphosphonic acid and N-donor ligands

Two novel cadmium diphosphonates [Cd(cis-H{sub 4}BDPP)(2,2 Prime -bipy){sub 2}]{center_dot}(trans-H{sub 2}BDPP)]{sub n} (1) and [Cd(trans-H{sub 2}BDPP)(phen)]{sub n} (2) (H{sub 4}BDPP=p-xylenediphosphonic acid, phen=1,10-phenanthroline, 2,2 Prime -bipy=2,2 Prime -bipyridine) were hydrothermally synthesized from p-xylenediphosphonic acid and CdSO{sub 4}{center_dot}3H{sub 2}O with phen or 2,2 Prime -bipy as second ligand components and characterized by means of elemental analyses, IR, TG analysis, luminescence spectroscopy and single crystal X-ray diffraction. Compound 1 consists of a novel one-dimensional (1D) sinusoidal [Cd(cis-H{sub 4}BDPP)(2,2 Prime -bipy){sub 2}] chains and trans-H{sub 2}BDPP anions. Compound 2 possesses a three-dimensional architecture built from double zigzag -Cd-O-P-O-Cd- chains pillared by trans-p-xylylenediphosphonate ligands from four different directions. There are hexagonal channels running along the c-axis and the coordinated phen ligands suspend in the hexagonal channels. The results indicate that p-xylenediphosphonic acid can adopt varied coordination modes and conformations in the formation of the complexes and the influence of the N-donor ligands on the structure of the complexes is discussed. - Graphical abstract: Two new cadmium diphosphonates were obtained by using two different auxiliary ligands. The influence of the N-donor ligands on the structure of the complexes is discussed. Highlights: Black-Right-Pointing-Pointer The first example of cadmium(II)-p-xylenediphosphonates templated by second ligand. Black-Right-Pointing-Pointer The role of size of the auxiliary ligand on the structure of cadmium p-xylenediphosphonates. Black-Right-Pointing-Pointer The cis and trans configurations of p-xylenediphosphonates exist in the same crystal structure. Black-Right-Pointing-Pointer Three-dimensional 4-connected framework with PtS network topology.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2011

Predictive modelling for EAST divertor operation

The predictive modelling study of the divertor operation in EAST tokamak [B. Wan et al., Nucl. Fusion 49, 104011 (2009)] with double null (DN) configuration is carried out by using the two-dimensional edge plasma code B2.5-SOLPS5.0 [D. P. Coster, X. Bonnin et al., J. Nucl. Mater. 337-339, 366 (2005)]. The modelling study includes the particle and power balance in the scrape-off-layer (SOL), the operation parameters of plasma density, temperature and plasma heat fluxes at the separatrix, the target plates and the wall, and the effect of the gas puffing, drifts, and vertical target plate on the divertor operation. The fluid model for the edge plasma is applied using the real magnetohydrodynamic (MHD) equilibrium from the MHD equilibrium code EFIT [L. L. Lao et al., Nucl. Fusion 25, 1611 (1985)] and the real divertor geometry in the device. Before EAST tokamak starts its experimental programme of divertor operation, the modelling plays an important role in the design of its experimental programme and the optimization of the divertor operation parameters. Based on the modelling results, EAST divertor can operate over a large wide of plasma parameters with different regimes. For a heating power of 8 MW and an edge density at core-SOL interface N{sub edge} = 0.8 x 10{sup 19}1/m{sup 3} and N{sub edge} = 1.3 x 10{sup 19}1/m{sup 3}, the EAST divertor begins access to the high recycling operation regime at the outer and inner target plates, respectively, where the plasma temperature and the heat fluxes at the target plates decrease. The gas puffing can increase the plasma density at the separatrix and trigger the transition from the high recycling operation into detachment at the target plates. When E x B and B x {nabla}B drifts are taken into account, the asymmetry of plasma parameters and heat fluxes between up-down SOLs can be found. The vertical target plate in EAST divertor can reduce the peak values of heat fluxes at the target plate and enables detachment at lower plasma density. The divertor with the vertical target plate can be considered as a possible option for EAST divertor upgrade in the future.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗