A three dimensional bounce-averaged Fokker-Planck （FP） numerical code has been newly developed based on fully implicit iterative solving method, and relativistic effect is also included in the code. The code has bee...A three dimensional bounce-averaged Fokker-Planck （FP） numerical code has been newly developed based on fully implicit iterative solving method, and relativistic effect is also included in the code. The code has been tested against various benchmark cases： Ohmic con ductivity in the presence of weak Ohmic electric field, runaway losses of electrons in the presence of strong Ohmic electric field, lower hybrid current drive and electron cyclotron current drive via two- or three-dimensional simulation. All the test cases run fast and correctly during calculations. As a result, the code provides a set of powerful tools for studying radio frequency wave heating and current drive in tokamak plasmas.展开更多
In the present paper,we first derive the eigenmode equation of the ideal ballooning mode in tokamak plasmas using a gyrokinetic equation.It is shown that the gyrokinetic eigenmode equation can be reduced to the magnet...In the present paper,we first derive the eigenmode equation of the ideal ballooning mode in tokamak plasmas using a gyrokinetic equation.It is shown that the gyrokinetic eigenmode equation can be reduced to the magnetohydrodynamic（MHD） form in the long wavelength limit when kinetic effects are ignored.Then,the global gyrokinetic toroidal code（GTC） is applied for simulations of the edge-localized ideal ballooning modes.The obtained mode structures are compared with the results of ideal MHD simulations.The observed scaling of the linear growth rate with the toroidal mode number is consistent with the ideal MHD theory.The simulation results verify the GTC capability of simulating MHD processes in toroidal plasmas.展开更多
The high confinement mode （H-mode） operation is recently obtained in HL-2A divertor configuration, the corresponding edge localized mode （ELM） is recognized as being of type III. Time intervals in ELM time series ...The high confinement mode （H-mode） operation is recently obtained in HL-2A divertor configuration, the corresponding edge localized mode （ELM） is recognized as being of type III. Time intervals in ELM time series are analysed to obtain the information about the ELM process. Signatures of unstable periodic orbits （UPOs） are detected, which are indicators of chaos and may be used to control the big ELM events.展开更多
It is crucial to increase the total stored energy by realizing the transition from a low confinement （L-mode） state to a high confinement （H-mode） state in magnetic confinement fusion. The L-H transition process i...It is crucial to increase the total stored energy by realizing the transition from a low confinement （L-mode） state to a high confinement （H-mode） state in magnetic confinement fusion. The L-H transition process is simulated by using the predictive transport code based on Weiland＇s fluid model. Based on the equilibrium parameters obtained from equilibrium fitting （EFIT） in the experiment, the electron density ne, electron temperature Te, ion temperatures lq, ion poloidal Vp, and toroidal momenta Vt are simulated self-consistently. The L-H transition dynamic behaviors with the formation of the transport barriers of ion and electron temperatures, the electron density, and the ion toroidal momenta are analyzed. During the L-H transition, the strong poloidal flow shear in the edge transport barrier region is observed. The crashes of the electron and ion temperature pedestals are also observed during the L-H transition. The effects of the heating and particle sources on the L-H transition process are studied systematically, and the critical power threshold of the L-H transition is also found.展开更多
In order to describe the characterization of resistive drift-wave nuctuauon in a [OKalnaK plasma, a coup^e~a lllVlbt;IU two-dimensional Hasegawa-Wakatani model is investigated. Two groups of new analytic solutions wit...In order to describe the characterization of resistive drift-wave nuctuauon in a [OKalnaK plasma, a coup^e~a lllVlbt;IU two-dimensional Hasegawa-Wakatani model is investigated. Two groups of new analytic solutions with and without phase shift between the fluctuant density and the ftuctuant potential are obtained by using the special function transformation method. It is demonstrated that the fluctuant potential shares similar spatio-temporal variations with the density. It is found from the solutions without phase shift that the effect of the diffusion and adiabaticity on the fluctuant density is quite complex, and that the fuctuation may be controlled through the adiabaticity and diffusion. By using the typical parameters in the quasi-adiabatic regime in the solutions with phase contours become dense toward the plasma edge and the distribution in the tokamak edge. shift, it is shown that the density gradient becomes larger as the contours have irregular structures, which reveal the nonuniform展开更多
In order to estimate the electron temperature soft x-ray imaging diagnostics using a double filter technique has been developed in the HT-7 tokamak. The chosen thicknesses of the Be foil are 12.5 μm and 70 μm, respe...In order to estimate the electron temperature soft x-ray imaging diagnostics using a double filter technique has been developed in the HT-7 tokamak. The chosen thicknesses of the Be foil are 12.5 μm and 70 μm, respectively. In this article both the main design of the diagnostic configuration and the method to estimate the electron temperature are presented. The results agree with those estimated from the soft x-ray pulse height analyzer （PHA）. The main causes of systematic error have also been investigated.展开更多
A code named LARWM with non-ideal magnetohydrodynamic equations in cylindrical model is used to describe the instability in Tokamak plasma surrounded by a conducting wall with finite resistivity. We mainly take three ...A code named LARWM with non-ideal magnetohydrodynamic equations in cylindrical model is used to describe the instability in Tokamak plasma surrounded by a conducting wall with finite resistivity. We mainly take three factors related to the shear equilibrium plasma flow into consideration to study the stabilizing effect of the shear flow on the resistive wall modes （RWMs）. The three factors are the velocity amplitude of flow, the shear rate of flow on plasma surface, and the inertial energy of equilibrium plasma flow. In addition, a local shear plasma flow is also calculated by the LARWM code. Consequently, it is found that the inertial energy of the shear equilibrium plasma flow has an important role in the stabilization of the RWMs.展开更多
基金supported by National Natural Science Foundation of China(Nos.11375085,11205086,and 11105071)the Construct Program of Fusion and Plasma Physics Innovation Team in Hunan Province,China(No.NHXTD03)
文摘A three dimensional bounce-averaged Fokker-Planck （FP） numerical code has been newly developed based on fully implicit iterative solving method, and relativistic effect is also included in the code. The code has been tested against various benchmark cases： Ohmic con ductivity in the presence of weak Ohmic electric field, runaway losses of electrons in the presence of strong Ohmic electric field, lower hybrid current drive and electron cyclotron current drive via two- or three-dimensional simulation. All the test cases run fast and correctly during calculations. As a result, the code provides a set of powerful tools for studying radio frequency wave heating and current drive in tokamak plasmas.
基金supported by U.S.Department of Energy(DOE) SciDAC GSEP Center and National Special Research Program of China for ITER
文摘In the present paper,we first derive the eigenmode equation of the ideal ballooning mode in tokamak plasmas using a gyrokinetic equation.It is shown that the gyrokinetic eigenmode equation can be reduced to the magnetohydrodynamic（MHD） form in the long wavelength limit when kinetic effects are ignored.Then,the global gyrokinetic toroidal code（GTC） is applied for simulations of the edge-localized ideal ballooning modes.The obtained mode structures are compared with the results of ideal MHD simulations.The observed scaling of the linear growth rate with the toroidal mode number is consistent with the ideal MHD theory.The simulation results verify the GTC capability of simulating MHD processes in toroidal plasmas.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10990213)
文摘The high confinement mode （H-mode） operation is recently obtained in HL-2A divertor configuration, the corresponding edge localized mode （ELM） is recognized as being of type III. Time intervals in ELM time series are analysed to obtain the information about the ELM process. Signatures of unstable periodic orbits （UPOs） are detected, which are indicators of chaos and may be used to control the big ELM events.
基金supported by the Funds of the Youth Innovation Team of Science and Technology in Sichuan Province,China(Grant No.2014TD0023)the National Natural Science Foundation of China(Grant Nos.11447228 and 11205053)the China National Magnetic Confinement Fusion Science Program(Grant No.2013GB107001)
文摘It is crucial to increase the total stored energy by realizing the transition from a low confinement （L-mode） state to a high confinement （H-mode） state in magnetic confinement fusion. The L-H transition process is simulated by using the predictive transport code based on Weiland＇s fluid model. Based on the equilibrium parameters obtained from equilibrium fitting （EFIT） in the experiment, the electron density ne, electron temperature Te, ion temperatures lq, ion poloidal Vp, and toroidal momenta Vt are simulated self-consistently. The L-H transition dynamic behaviors with the formation of the transport barriers of ion and electron temperatures, the electron density, and the ion toroidal momenta are analyzed. During the L-H transition, the strong poloidal flow shear in the edge transport barrier region is observed. The crashes of the electron and ion temperature pedestals are also observed during the L-H transition. The effects of the heating and particle sources on the L-H transition process are studied systematically, and the critical power threshold of the L-H transition is also found.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10905038,11275123,and 11365017)the National ITER Plans Program of China(Grant No.2009GB105002)the Natural Science Foundation of Jiangxi Province,China(Grant Nos.2008GZS0045 and 2009GZW0026)
文摘In order to describe the characterization of resistive drift-wave nuctuauon in a [OKalnaK plasma, a coup^e~a lllVlbt;IU two-dimensional Hasegawa-Wakatani model is investigated. Two groups of new analytic solutions with and without phase shift between the fluctuant density and the ftuctuant potential are obtained by using the special function transformation method. It is demonstrated that the fluctuant potential shares similar spatio-temporal variations with the density. It is found from the solutions without phase shift that the effect of the diffusion and adiabaticity on the fluctuant density is quite complex, and that the fuctuation may be controlled through the adiabaticity and diffusion. By using the typical parameters in the quasi-adiabatic regime in the solutions with phase contours become dense toward the plasma edge and the distribution in the tokamak edge. shift, it is shown that the density gradient becomes larger as the contours have irregular structures, which reveal the nonuniform
基金supported by National Natural Science Foundation of China (Nos. 10375070, 10305012)
文摘In order to estimate the electron temperature soft x-ray imaging diagnostics using a double filter technique has been developed in the HT-7 tokamak. The chosen thicknesses of the Be foil are 12.5 μm and 70 μm, respectively. In this article both the main design of the diagnostic configuration and the method to estimate the electron temperature are presented. The results agree with those estimated from the soft x-ray pulse height analyzer （PHA）. The main causes of systematic error have also been investigated.
基金the National Natural Science Foundation of China(Grant Nos.11105065 and 11275041)the National Basic Research Program of China(Grant Nos.2008CB717801,2008CB787103,2009GB105004,and 2010GB106002)
文摘A code named LARWM with non-ideal magnetohydrodynamic equations in cylindrical model is used to describe the instability in Tokamak plasma surrounded by a conducting wall with finite resistivity. We mainly take three factors related to the shear equilibrium plasma flow into consideration to study the stabilizing effect of the shear flow on the resistive wall modes （RWMs）. The three factors are the velocity amplitude of flow, the shear rate of flow on plasma surface, and the inertial energy of equilibrium plasma flow. In addition, a local shear plasma flow is also calculated by the LARWM code. Consequently, it is found that the inertial energy of the shear equilibrium plasma flow has an important role in the stabilization of the RWMs.
