Shaping effects of the E-fishbone in tokamaks are investigated. Coordinates related to the Solov＇ev configuration are used to calculate the precession frequency and kinetic contribu- tion. It is shown that elongation...Shaping effects of the E-fishbone in tokamaks are investigated. Coordinates related to the Solov＇ev configuration are used to calculate the precession frequency and kinetic contribu- tion. It is shown that elongation does not change the precession frequency and the kinetic energy. Growth rates of the E-fishbone vary with elongation which essentially has destabilizing effects. For elongated tokamaks, triangularity has a stabilizing effect on the modes which play a compensative role. The results may apply to Sunist.展开更多
Solov＇ev type analytic equilibria of toroidally axi-symmetric plasmas are extended to include the anisotropic pressure and parallel flow effect. It is shown that the combined effects of the parallel flow and the anis...Solov＇ev type analytic equilibria of toroidally axi-symmetric plasmas are extended to include the anisotropic pressure and parallel flow effect. It is shown that the combined effects of the parallel flow and the anisotropic pressure can be added to give a modified Grad-Shafranov equation. Effects of the anisotropic pressure and the parallel flow on the equilibrium＇s properties such as the safety factor and the magnetic well are clarified. The most prominent characteristic of these two effects is the deviations of both the p//-contours and the p⊥-contours from the magnetic flux contours.展开更多
Analytical solutions of the Grad-Shafranov equation are always useful because of their convenience and accuracy in theoretical study of stability, transport and kinetic analysis. For the quasi-uniform toroidal current...Analytical solutions of the Grad-Shafranov equation are always useful because of their convenience and accuracy in theoretical study of stability, transport and kinetic analysis. For the quasi-uniform toroidal current density case, the so-called Solov＇ev configuration is the earliest one that was widely used for the magnetohydrodynamic （MHD） stability analysis and also used as benchmark for equilibrium code studies later.展开更多
By employing the NCEP/NCAR reanalysis data （1000-10 hPa, 2.5°×2.5°）, the impact of the vortex in the easterlies （EV） over the tropical upper troposphere on the zonal movement of the western Pacific ...By employing the NCEP/NCAR reanalysis data （1000-10 hPa, 2.5°×2.5°）, the impact of the vortex in the easterlies （EV） over the tropical upper troposphere on the zonal movement of the western Pacific subtropical anticyclone （WPSA） during 19-25 June 2003 is analyzed in this paper. It is shown that the EV can extend from middle troposphere to the height of 50 hPa, reaching a maximum at 200 hPa. The vertical thermal distribution appears to be ＂warmer in the upper layer and colder in the lower layer＂. The WPSA retreats eastward abnormally when the EV and the vortex in the westerlies （WV） encounter around the same longitude while they move toward each other. It is also shown that the vorticity variation extends from the troposphere to the height of 50 hPa, with the most prominent change occurring at 200 hPa by the diagnostic analyses of the vertical vorticity equation. The WPSA appears to retreat abnormally eastward while the negative/positive vorticity change becomes stronger near the east/west side of the EV, and the areas with positive vorticity tendency both in the EV and WV join together into one belt along 130°E during the process of the EV and the WV moving toward each other. In the vorticity equation, the positive contribution caused by the horizontal advection term is the maximum, and the minimum is caused by theβ effect. It is also found that enhanced horizontal vorticity advection andβ effect, as well as the ＂barotropic development＂ resulted from the in-phase superposition of the southerly and the northerly winds in the easterlies and westerlies near 130~E, are in agreement with the WPSA eastward retreat.展开更多
Determining the travel intention of residents with shared electric vehicles(EVs)is significant for promoting the development of low-carbon transportation,considering that common problems such as high idle rate and lac...Determining the travel intention of residents with shared electric vehicles(EVs)is significant for promoting the development of low-carbon transportation,considering that common problems such as high idle rate and lack of attractiveness still exist.To this end,a structural equation model(SEM)based on the theory of multiple motivations is proposed in this paper.First,the influencing motivations for EV sharing are divided into three categories:consumer-driven,program-driven,and enterprise-driven motivations.Then,the intentions of residents in Shanghai to travel with shared EVs are obtained through a survey questionnaire.Finally,an SEM is constructed to analyze quantitatively the impact of different motivations on the travel intention.The results show that consumer-driven motivations with impact weights from 0.14 to 0.63 have the overwhelming impact on travel intention,compared to program-driven motivations with impact weights from−0.14 to 0.15 and enterprise-driven motivations with impact weights from 0.02 to 0.06.In terms of consumer-driven motivations,the weight of green travel awareness is the highest.The implications of these results on the policy to enable large-scale implementation of shared EVs are discussed from the perspectives of the resident,enterprise,and government.展开更多
基金supported by National Natural Science Foundation of China (Nos. 11261140327, 11005035, 11175058)National Magnetic Confinement Fusion Science Program of China (No. 2009GB105002)
文摘Shaping effects of the E-fishbone in tokamaks are investigated. Coordinates related to the Solov＇ev configuration are used to calculate the precession frequency and kinetic contribu- tion. It is shown that elongation does not change the precession frequency and the kinetic energy. Growth rates of the E-fishbone vary with elongation which essentially has destabilizing effects. For elongated tokamaks, triangularity has a stabilizing effect on the modes which play a compensative role. The results may apply to Sunist.
基金supported by National Natural Science Foundation of China (NO. 10375018)
文摘Solov＇ev type analytic equilibria of toroidally axi-symmetric plasmas are extended to include the anisotropic pressure and parallel flow effect. It is shown that the combined effects of the parallel flow and the anisotropic pressure can be added to give a modified Grad-Shafranov equation. Effects of the anisotropic pressure and the parallel flow on the equilibrium＇s properties such as the safety factor and the magnetic well are clarified. The most prominent characteristic of these two effects is the deviations of both the p//-contours and the p⊥-contours from the magnetic flux contours.
基金Supported by the National Natural Science Foundation of China （10375018）
文摘Analytical solutions of the Grad-Shafranov equation are always useful because of their convenience and accuracy in theoretical study of stability, transport and kinetic analysis. For the quasi-uniform toroidal current density case, the so-called Solov＇ev configuration is the earliest one that was widely used for the magnetohydrodynamic （MHD） stability analysis and also used as benchmark for equilibrium code studies later.
基金Supported by the National Natural Science Foundation of China under Grant No. 40875030Heavy Rain Opening Foun-dation under Grant No. IHR2005K04
文摘By employing the NCEP/NCAR reanalysis data （1000-10 hPa, 2.5°×2.5°）, the impact of the vortex in the easterlies （EV） over the tropical upper troposphere on the zonal movement of the western Pacific subtropical anticyclone （WPSA） during 19-25 June 2003 is analyzed in this paper. It is shown that the EV can extend from middle troposphere to the height of 50 hPa, reaching a maximum at 200 hPa. The vertical thermal distribution appears to be ＂warmer in the upper layer and colder in the lower layer＂. The WPSA retreats eastward abnormally when the EV and the vortex in the westerlies （WV） encounter around the same longitude while they move toward each other. It is also shown that the vorticity variation extends from the troposphere to the height of 50 hPa, with the most prominent change occurring at 200 hPa by the diagnostic analyses of the vertical vorticity equation. The WPSA appears to retreat abnormally eastward while the negative/positive vorticity change becomes stronger near the east/west side of the EV, and the areas with positive vorticity tendency both in the EV and WV join together into one belt along 130°E during the process of the EV and the WV moving toward each other. In the vorticity equation, the positive contribution caused by the horizontal advection term is the maximum, and the minimum is caused by theβ effect. It is also found that enhanced horizontal vorticity advection andβ effect, as well as the ＂barotropic development＂ resulted from the in-phase superposition of the southerly and the northerly winds in the easterlies and westerlies near 130~E, are in agreement with the WPSA eastward retreat.
基金the National Natural Science Founda-tion of China(Nos.71971139 and 72201172)。
文摘Determining the travel intention of residents with shared electric vehicles(EVs)is significant for promoting the development of low-carbon transportation,considering that common problems such as high idle rate and lack of attractiveness still exist.To this end,a structural equation model(SEM)based on the theory of multiple motivations is proposed in this paper.First,the influencing motivations for EV sharing are divided into three categories:consumer-driven,program-driven,and enterprise-driven motivations.Then,the intentions of residents in Shanghai to travel with shared EVs are obtained through a survey questionnaire.Finally,an SEM is constructed to analyze quantitatively the impact of different motivations on the travel intention.The results show that consumer-driven motivations with impact weights from 0.14 to 0.63 have the overwhelming impact on travel intention,compared to program-driven motivations with impact weights from−0.14 to 0.15 and enterprise-driven motivations with impact weights from 0.02 to 0.06.In terms of consumer-driven motivations,the weight of green travel awareness is the highest.The implications of these results on the policy to enable large-scale implementation of shared EVs are discussed from the perspectives of the resident,enterprise,and government.
