Many magnetohydrodynamic stability analyses require generation of a set of equilibria with a fixed safety factor q-profile while varying other plasma parameters.A neural network(NN)-based approach is investigated that...Many magnetohydrodynamic stability analyses require generation of a set of equilibria with a fixed safety factor q-profile while varying other plasma parameters.A neural network(NN)-based approach is investigated that facilitates such a process.Both multilayer perceptron(MLP)-based NN and convolutional neural network(CNN)models are trained to map the q-profile to the plasma current density J-profile,and vice versa,while satisfying the Grad–Shafranov radial force balance constraint.When the initial target models are trained,using a database of semianalytically constructed numerical equilibria,an initial CNN with one convolutional layer is found to perform better than an initial MLP model.In particular,a trained initial CNN model can also predict the q-or J-profile for experimental tokamak equilibria.The performance of both initial target models is further improved by fine-tuning the training database,i.e.by adding realistic experimental equilibria with Gaussian noise.The fine-tuned target models,referred to as fine-tuned MLP and fine-tuned CNN,well reproduce the target q-or J-profile across multiple tokamak devices.As an important application,these NN-based equilibrium profile convertors can be utilized to provide a good initial guess for iterative equilibrium solvers,where the desired input quantity is the safety factor instead of the plasma current density.展开更多
Effects of three-dimensional(3D)magnetic field perturbations due to feedback control of an unstable n=1(n is toroidal mode number)resistive wall mode(RWM)on the energetic particle(EP)losses are systematically investig...Effects of three-dimensional(3D)magnetic field perturbations due to feedback control of an unstable n=1(n is toroidal mode number)resistive wall mode(RWM)on the energetic particle(EP)losses are systematically investigated for the HL-3 tokamak.The MARS-F(Liu et al 2000 Phys.Plasmas 73681)code,facilitated by the test particle guiding center tracing module REORBIT,is utilized for the study.The RWM is found to generally produce no EP loss for cocurrent particles in HL-3.Assuming the same perturbation level at the sensor location for the close-loop system,feedback produces nearly the same loss of counter-current EPs compared to the open-loop case.Assuming however that the sensor signal is ten times smaller in the close-loop system than the open-loop counter part(reflecting the fact that the RWM is more stable with feedback),the counter-current EP loss is found significantly reduced in the former.Most of EP losses occur only for particles launched close to the plasma edge,while particles launched further away from the plasma boundary experience much less loss.The strike points of lost EPs on the HL-3 limiting surface become more scattered for particles launched closer to the plasma boundary.Taking into account the full gyro-orbit of particles while approaching the limiting surface,REORBIT finds slightly enhanced loss fraction.展开更多
目的建立采用全自动氨基酸分析仪测定黄酒中游离氨基酸的含量的方法,并测定不同年份的黄酒中游离氨基酸含量。方法黄酒经氮气吹干复溶后,过膜,使用全自动氨基酸分析仪进行测定。结果方法检出限达到0.01 mg/100 m L,回收率达到90.1%~101....目的建立采用全自动氨基酸分析仪测定黄酒中游离氨基酸的含量的方法,并测定不同年份的黄酒中游离氨基酸含量。方法黄酒经氮气吹干复溶后,过膜,使用全自动氨基酸分析仪进行测定。结果方法检出限达到0.01 mg/100 m L,回收率达到90.1%~101.2%,均符合检测要求。测定结果显示,黄酒中含有脯氨酸、亮氨酸等多种氨基酸,具有较高的营养价值,且不同酒龄的黄酒中氨基酸的总含量不同,各氨基酸含量随年份的不同也会发生变化。结论该方法前处理简单、快速,测定结果准确、可靠,能够满足黄酒中氨基酸的日常检测工作,适用于大量样品的定性定量分析。展开更多
Transport of fast ions is a crucial issue during the operation of ITER.Redistribution of neutral beam injection(NBI)fast ions by the ideal internal magnetohydrodynamic(MHD)instabilities in ITER is studied utilizing th...Transport of fast ions is a crucial issue during the operation of ITER.Redistribution of neutral beam injection(NBI)fast ions by the ideal internal magnetohydrodynamic(MHD)instabilities in ITER is studied utilizing the guiding-center code ORBIT(White R B and Chance M S 1984Phys.Fluids 272455).Effects of the perturbation amplitude A of the internal kink,the perturbation frequency f of the fishbone instability,and the toroidal mode number n of the internal kink are investigated,respectively,in this work.The n=1 internal kink mode can cause NBI fast ions transporting in real space from regions of 0<s≤0.32 to 0.32<s≤0.53,where s labels the normalized plasma radial coordinate.The transport of fast ions is greater as the perturbation amplitude increases.The maximum relative change of the number of fast ions approaches 5%when the perturbation amplitude rises to 500 G.A strong transport is generated between the regions of 0<s≤0.05 and 0.05<s≤0.12 in the presence of the fishbone instability.Higher frequency results in greater transport,and the number of fast ions in 0<s≤0.05 is reduced by 30%at the fishbone frequency of 100 k Hz.Perturbations with higher n will lead to the excursion of fast ion transport regions outward along the radial direction.The loss of fast ions,however,is not affected by the internal MHD perturbation.Strong transport from 0<s≤0.05 to 0.05<s≤0.12 does not influence the plasma heating power of ITER,since the NBI fast ions are still located in the plasma core.On the other hand,the influence of fast ion transport from 0<s≤0.32 to 0.32<s≤0.53 needs further study.展开更多
The kinetic effects of thermal particles and fast ions on internal kink(IK)mode are numerically investigated by the MHD-kinetic hybrid code MARS-K.It is shown that either thermal particles or fast ions have stabilizin...The kinetic effects of thermal particles and fast ions on internal kink(IK)mode are numerically investigated by the MHD-kinetic hybrid code MARS-K.It is shown that either thermal particles or fast ions have stabilizing influence on IK.However,the former can not fully stabilize IK,and the later can suppress the IK.In addition,the synergistic effect from thermal particles and fast ions induces more stronger damping on IK.The kinetic effects from particles significantly raise the critical value of poloidal beta(βpcrit)for driving IK in the toroidal plasma.This implies a method of controlling IK or sawtooth in the high-βp discharge scenario of tokamak.It is noted that,at the q=1 rational surface,mode structure becomes more sharp due to the self-consistent modification by particles’kinetic effect.展开更多
基金supported by National Natural Science Foundation of China (Nos. 12205033, 12105317, 11905022 and 11975062)Dalian Youth Science and Technology Project (No. 2022RQ039)+1 种基金the Fundamental Research Funds for the Central Universities (No. 3132023192)the Young Scientists Fund of the Natural Science Foundation of Sichuan Province (No. 2023NSFSC1291)
文摘Many magnetohydrodynamic stability analyses require generation of a set of equilibria with a fixed safety factor q-profile while varying other plasma parameters.A neural network(NN)-based approach is investigated that facilitates such a process.Both multilayer perceptron(MLP)-based NN and convolutional neural network(CNN)models are trained to map the q-profile to the plasma current density J-profile,and vice versa,while satisfying the Grad–Shafranov radial force balance constraint.When the initial target models are trained,using a database of semianalytically constructed numerical equilibria,an initial CNN with one convolutional layer is found to perform better than an initial MLP model.In particular,a trained initial CNN model can also predict the q-or J-profile for experimental tokamak equilibria.The performance of both initial target models is further improved by fine-tuning the training database,i.e.by adding realistic experimental equilibria with Gaussian noise.The fine-tuned target models,referred to as fine-tuned MLP and fine-tuned CNN,well reproduce the target q-or J-profile across multiple tokamak devices.As an important application,these NN-based equilibrium profile convertors can be utilized to provide a good initial guess for iterative equilibrium solvers,where the desired input quantity is the safety factor instead of the plasma current density.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2022YFE03090000 and 2022YFE03060002)National Natural Science Foundation of China(No.12375214)+3 种基金China National Nuclear Corporation Fundamental Research Program(No.CNNC-JCYJ-202236)Innovation Program of Southwestern Institute of Physics(No.202301XWCX006-04)supported by Youth Science and Technology Innovation Team of Sichuan Province(No.2022JDTD0003)US DoE Office of Science(Nos.DE-FG02-95ER54309 and DE-FC02-04ER54698)。
文摘Effects of three-dimensional(3D)magnetic field perturbations due to feedback control of an unstable n=1(n is toroidal mode number)resistive wall mode(RWM)on the energetic particle(EP)losses are systematically investigated for the HL-3 tokamak.The MARS-F(Liu et al 2000 Phys.Plasmas 73681)code,facilitated by the test particle guiding center tracing module REORBIT,is utilized for the study.The RWM is found to generally produce no EP loss for cocurrent particles in HL-3.Assuming the same perturbation level at the sensor location for the close-loop system,feedback produces nearly the same loss of counter-current EPs compared to the open-loop case.Assuming however that the sensor signal is ten times smaller in the close-loop system than the open-loop counter part(reflecting the fact that the RWM is more stable with feedback),the counter-current EP loss is found significantly reduced in the former.Most of EP losses occur only for particles launched close to the plasma edge,while particles launched further away from the plasma boundary experience much less loss.The strike points of lost EPs on the HL-3 limiting surface become more scattered for particles launched closer to the plasma boundary.Taking into account the full gyro-orbit of particles while approaching the limiting surface,REORBIT finds slightly enhanced loss fraction.
文摘目的建立采用全自动氨基酸分析仪测定黄酒中游离氨基酸的含量的方法,并测定不同年份的黄酒中游离氨基酸含量。方法黄酒经氮气吹干复溶后,过膜,使用全自动氨基酸分析仪进行测定。结果方法检出限达到0.01 mg/100 m L,回收率达到90.1%~101.2%,均符合检测要求。测定结果显示,黄酒中含有脯氨酸、亮氨酸等多种氨基酸,具有较高的营养价值,且不同酒龄的黄酒中氨基酸的总含量不同,各氨基酸含量随年份的不同也会发生变化。结论该方法前处理简单、快速,测定结果准确、可靠,能够满足黄酒中氨基酸的日常检测工作,适用于大量样品的定性定量分析。
基金supported by the National Key Research and Development Program of China(Nos.2022YFE03060002,2019YFE03090100)by the Innovation Program of Southwestern Institute of Physics(No.202001XWCXRC001)partly supported by the Youth Science and Technology Innovation Team of Sichuan Province(No.2022JDTD0003)。
文摘Transport of fast ions is a crucial issue during the operation of ITER.Redistribution of neutral beam injection(NBI)fast ions by the ideal internal magnetohydrodynamic(MHD)instabilities in ITER is studied utilizing the guiding-center code ORBIT(White R B and Chance M S 1984Phys.Fluids 272455).Effects of the perturbation amplitude A of the internal kink,the perturbation frequency f of the fishbone instability,and the toroidal mode number n of the internal kink are investigated,respectively,in this work.The n=1 internal kink mode can cause NBI fast ions transporting in real space from regions of 0<s≤0.32 to 0.32<s≤0.53,where s labels the normalized plasma radial coordinate.The transport of fast ions is greater as the perturbation amplitude increases.The maximum relative change of the number of fast ions approaches 5%when the perturbation amplitude rises to 500 G.A strong transport is generated between the regions of 0<s≤0.05 and 0.05<s≤0.12 in the presence of the fishbone instability.Higher frequency results in greater transport,and the number of fast ions in 0<s≤0.05 is reduced by 30%at the fishbone frequency of 100 k Hz.Perturbations with higher n will lead to the excursion of fast ion transport regions outward along the radial direction.The loss of fast ions,however,is not affected by the internal MHD perturbation.Strong transport from 0<s≤0.05 to 0.05<s≤0.12 does not influence the plasma heating power of ITER,since the NBI fast ions are still located in the plasma core.On the other hand,the influence of fast ion transport from 0<s≤0.32 to 0.32<s≤0.53 needs further study.
基金the National Key R&D Program of China(Grant No.2019YFE03050003)the National Magnetic Confinement Fusion Science Program(Grant No.2018YFE0304103)the National Natural Science Foundation of China(Grant Nos.11775067 and11905067)。
文摘The kinetic effects of thermal particles and fast ions on internal kink(IK)mode are numerically investigated by the MHD-kinetic hybrid code MARS-K.It is shown that either thermal particles or fast ions have stabilizing influence on IK.However,the former can not fully stabilize IK,and the later can suppress the IK.In addition,the synergistic effect from thermal particles and fast ions induces more stronger damping on IK.The kinetic effects from particles significantly raise the critical value of poloidal beta(βpcrit)for driving IK in the toroidal plasma.This implies a method of controlling IK or sawtooth in the high-βp discharge scenario of tokamak.It is noted that,at the q=1 rational surface,mode structure becomes more sharp due to the self-consistent modification by particles’kinetic effect.
