First order reversal curves （FORC） of nanocomposite Nd2Fe14B/Fe3B magnetic materials were measured to attain a FORC diagram, which characterizes reversible magnetization, irreversible magnetization, and magnetic int...First order reversal curves （FORC） of nanocomposite Nd2Fe14B/Fe3B magnetic materials were measured to attain a FORC diagram, which characterizes reversible magnetization, irreversible magnetization, and magnetic interactions in a hysteresis system. Then, generalized mov- ing Preisach model （GMPM） was implemented based on the FORC diagram. Reversible and irreversible magnetizations shown in FORCs and a FORC diagram were used as an input of GMPM. Coupling interaction between reversible and irreversible magnetizations was added when calculating reversible magnetization. Meanwhile, irreversible magnetic moments＇ interaction was approximately represented by mean field interaction. The result shows that the simulated main curves mostly coincide with the experimental curves.展开更多
A new eigen-mode equation for the tokamak high-n （the toroidal mode number） ideal magnetohydrodynamic （MHD） ballooning mode in tokamak plasmas is derived to include the toroidal effects that are significant for st...A new eigen-mode equation for the tokamak high-n （the toroidal mode number） ideal magnetohydrodynamic （MHD） ballooning mode in tokamak plasmas is derived to include the toroidal effects that are significant for stability of configurations with internal transport barriers （ITBs）, Fot tokamak equilibria of shift circular flux surfaces, these toroidal effects basically are the finite inverse aspect ratio and the Shafranov shift. The former yields the averaged favorable curvature stabilization while the latter further strengthens this effect, leading to a low shear stable channel connecting the first and second stability regions, and to the shrinkage of unstable region in the （8,α） diagram. The dependence of the critical shear, below which the plasma is stable, on these effects is given. These results are important for understanding the ITB physics to some regards.展开更多
For the effect of the collisional dissipation of fast electrons driven by the lower-hybrid waves, a predictive simulation is made for the HT-7 plasma. The simulation results show that the dissipation of fast electrons...For the effect of the collisional dissipation of fast electrons driven by the lower-hybrid waves, a predictive simulation is made for the HT-7 plasma. The simulation results show that the dissipation of fast electrons counteracts the effect of radial diffusion to some extent, thereby making the lower-hybrid driven current profile closer to the power deposition profile. So, in the case of an off-axis lower-hybrid wave power launching, the dissipation is helpful in maintaining a center-hollowed current profile in lower hybrid current drive （LHCD） plasmas, and thus possibly maintains the desired reversed magnetic shear.展开更多
文摘First order reversal curves （FORC） of nanocomposite Nd2Fe14B/Fe3B magnetic materials were measured to attain a FORC diagram, which characterizes reversible magnetization, irreversible magnetization, and magnetic interactions in a hysteresis system. Then, generalized mov- ing Preisach model （GMPM） was implemented based on the FORC diagram. Reversible and irreversible magnetizations shown in FORCs and a FORC diagram were used as an input of GMPM. Coupling interaction between reversible and irreversible magnetizations was added when calculating reversible magnetization. Meanwhile, irreversible magnetic moments＇ interaction was approximately represented by mean field interaction. The result shows that the simulated main curves mostly coincide with the experimental curves.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10135020 and 10375018.
文摘A new eigen-mode equation for the tokamak high-n （the toroidal mode number） ideal magnetohydrodynamic （MHD） ballooning mode in tokamak plasmas is derived to include the toroidal effects that are significant for stability of configurations with internal transport barriers （ITBs）, Fot tokamak equilibria of shift circular flux surfaces, these toroidal effects basically are the finite inverse aspect ratio and the Shafranov shift. The former yields the averaged favorable curvature stabilization while the latter further strengthens this effect, leading to a low shear stable channel connecting the first and second stability regions, and to the shrinkage of unstable region in the （8,α） diagram. The dependence of the critical shear, below which the plasma is stable, on these effects is given. These results are important for understanding the ITB physics to some regards.
基金supportcd by National Natural Science Foundation of China(No.10425526)
文摘For the effect of the collisional dissipation of fast electrons driven by the lower-hybrid waves, a predictive simulation is made for the HT-7 plasma. The simulation results show that the dissipation of fast electrons counteracts the effect of radial diffusion to some extent, thereby making the lower-hybrid driven current profile closer to the power deposition profile. So, in the case of an off-axis lower-hybrid wave power launching, the dissipation is helpful in maintaining a center-hollowed current profile in lower hybrid current drive （LHCD） plasmas, and thus possibly maintains the desired reversed magnetic shear.
