Particle-in-cell （PIC） simulation method has been proved to be a good candidate to study the interactions between plasmas and radio-frequency waves. However, for waves in the lower hybrid range of frequencies, a ful...Particle-in-cell （PIC） simulation method has been proved to be a good candidate to study the interactions between plasmas and radio-frequency waves. However, for waves in the lower hybrid range of frequencies, a full PIC simulation is not efficient due to its high computational cost. In this work, a gyro-kinetic electron and fully-kinetic ion （GeFi） particle simulation model is applied to study the propagations and mode conversion processes of lower hybrid waves （LHWs） in plasmas. With this method, the computational efficiency of LHW simulations is greatly increased by using a larger grid size and time step. The simulation results in the linear regime are validated by comparison with the linear theory.展开更多
Loss-cone instabilities are studied for linear fusion devices. The gyro-kinetic equation for such a configuration is rigorously constructed in terms of action-angle variables by making use of canonical transformation....Loss-cone instabilities are studied for linear fusion devices. The gyro-kinetic equation for such a configuration is rigorously constructed in terms of action-angle variables by making use of canonical transformation. The dispersion relation, including for the first time, finite bounce frequency is obtained and numerically solved. The loss-cone modes are found near ion-cyclotron frequency. The growth rates are greatly reduced and approaching zero with increasing beta value. The results suggest that loss-cone instabilities are unlikely to be threatening to linear fusion devices since a new longitudinal invariant is found and gives a constraint which helps confinement.展开更多
Understanding and modeling fast-ion stabilization of ion-temperature-gradient(ITG)driven microturbulence have profound implications for designing and optimizing future fusion reactors.In this work,an analytic model is...Understanding and modeling fast-ion stabilization of ion-temperature-gradient(ITG)driven microturbulence have profound implications for designing and optimizing future fusion reactors.In this work,an analytic model is presented,which describes the effect of fast ions on ITG mode.This model is derived from a bounce-average gyro-kinetic equation for trapped fast ions and ballooning transformation for ITG mode.In addition to dilution,strong wave-fast-ion resonant interaction is involved in this model.Based on numerical calculations,the effects of the main physical parameters are studied.The increasing density of fast ions will strengthen the effects of fast ions.The effect of wave-particle resonance strongly depends on the temperature of fast ions.Furthermore,both increasing density gradient and the ratio of the temperature and density gradients can strengthen the stabilization of fast ions in ITG mode.Finally,the influence of resonance broadening of wave-particle interaction is discussed.展开更多
基金supported by Science Foundation of Institute of Plasma Physics Chinese Academy of Sciences(No.Y35ETY1304)the JSPSNRF-NSFC A3 Foresight Program in the Field of Plasma Physics(No.11261140328)+1 种基金National ITER Plans Program of China(No.2013GB111002)National Natural Science Foundation of China(No.11105178)
文摘Particle-in-cell （PIC） simulation method has been proved to be a good candidate to study the interactions between plasmas and radio-frequency waves. However, for waves in the lower hybrid range of frequencies, a full PIC simulation is not efficient due to its high computational cost. In this work, a gyro-kinetic electron and fully-kinetic ion （GeFi） particle simulation model is applied to study the propagations and mode conversion processes of lower hybrid waves （LHWs） in plasmas. With this method, the computational efficiency of LHW simulations is greatly increased by using a larger grid size and time step. The simulation results in the linear regime are validated by comparison with the linear theory.
基金supported by the Natural Science Foundation for Young Scientists of China (No. 11605143)National Natural Science Foundation of China (Nos. 11575055,11261140327,11005035,11205053)+3 种基金the project,Plasma Confinement in the Advanced Magnetic Mirror (WX-2015-01-01)the Open Research Subject of the Key Laboratory of Advanced Computation in Xihua University (Nos. szjj2017-011 and szjj2017-012)the Young Scholarship Plan of Xihua University (No. 0220170201)the National Key Research and Development Program of China (No. 2017YFE0300405)
文摘Loss-cone instabilities are studied for linear fusion devices. The gyro-kinetic equation for such a configuration is rigorously constructed in terms of action-angle variables by making use of canonical transformation. The dispersion relation, including for the first time, finite bounce frequency is obtained and numerically solved. The loss-cone modes are found near ion-cyclotron frequency. The growth rates are greatly reduced and approaching zero with increasing beta value. The results suggest that loss-cone instabilities are unlikely to be threatening to linear fusion devices since a new longitudinal invariant is found and gives a constraint which helps confinement.
基金National Natural Science Foundation of China(Nos.11822505,11835016 and 11675257)the Youth Innovation Promotion Association CAS,the Users with Excellence Program of Hefei Science Center CAS(No.2019HSC-UE013)+1 种基金the Fundamental Research Funds for the Central Universities(No.WK3420000008)the Collaborative Innovation Program of Hefei Science Center CAS(No.2019HSC-CIP014)。
文摘Understanding and modeling fast-ion stabilization of ion-temperature-gradient(ITG)driven microturbulence have profound implications for designing and optimizing future fusion reactors.In this work,an analytic model is presented,which describes the effect of fast ions on ITG mode.This model is derived from a bounce-average gyro-kinetic equation for trapped fast ions and ballooning transformation for ITG mode.In addition to dilution,strong wave-fast-ion resonant interaction is involved in this model.Based on numerical calculations,the effects of the main physical parameters are studied.The increasing density of fast ions will strengthen the effects of fast ions.The effect of wave-particle resonance strongly depends on the temperature of fast ions.Furthermore,both increasing density gradient and the ratio of the temperature and density gradients can strengthen the stabilization of fast ions in ITG mode.Finally,the influence of resonance broadening of wave-particle interaction is discussed.
