The dispersion relation and damping rate of kinetic Alfvén waves(KAWs) in a deuterium-tritium fusion plasma with slowing-down distributed α-particles are investigated using the kinetic theory. The variations of ...The dispersion relation and damping rate of kinetic Alfvén waves(KAWs) in a deuterium-tritium fusion plasma with slowing-down distributed α-particles are investigated using the kinetic theory. The variations of wave frequency and damping rate with respect to the α concentration(n_(α)/n_(e)) and perpendicular wave number(k_(⊥)) are studied from a numerical way. The results show that the fluctuation of α concentration slightly affects the frequency and damping rate of KAWs at low n_(α)/n_(e). In addition, the frequency and the damping rate increase as the k_(⊥) and the background temperature Te increase. For comparison, the calculations are performed also in the case of α-particles following an equivalent Maxwellian distribution. For a given k_(⊥), the value of the frequency obtained in the slowing-down distribution case is smaller than that obtained in the Maxwellian distribution case. Conversely, the value of the damping rate obtained in the slowing-down distribution case is slightly larger than that obtained in the Maxwellian distribution case.展开更多
A mixture of deuterium (D) and tritium (T) is the most likely fuel for laser-driven inertial confinement fusion (ICF) reactors and hence DD and DT are the fusion reactions that will fire these reactors in the future. ...A mixture of deuterium (D) and tritium (T) is the most likely fuel for laser-driven inertial confinement fusion (ICF) reactors and hence DD and DT are the fusion reactions that will fire these reactors in the future. Neutrons produced from the two reactions will escape from the burning plasma, in the reactor core, and they are the only products possible to be measured directly. DT/DD neutron ratio is crucial for evaluation of T/D fuel ratio, burn control, tritium cycle and alpha particle self-heating power. To measure this ratio experimentally, the neutron spectra of DD and DT reactions have to be measured separately and simultaneously under high neutron counting with sufficient statistics (typically within 10% error) in a very short time and these issues are mutually contradicted. That is why it is not plausible to measure this high priority ratio for reactor performance accurately. Precise calculations of the DT/DD neutron ratio are needed. Here, we introduce such calculations using a three dimensional (3-D) Monte Carlo code at energies up to 40 MeV (the predicted maximum ion acceleration energy with the available laser systems). In addition, the fusion power ratio of DD and DT reactions is calculated for the same energy range. The study indicates that for a mixture of 50% deuterium and 50% triton, with taking into account the reactions D(d,n)<sup>3</sup>He and T(d,n)<sup>4</sup>He, the optimum energy value for achieving the most efficient laser-driven ICF is 0.08 MeV.展开更多
Due to the existing limited dynamic range a camera cannot reveal all the details in a high-dynamic range scene. In order to solve this problem,this paper presents a multi-exposure fusion method for getting high qualit...Due to the existing limited dynamic range a camera cannot reveal all the details in a high-dynamic range scene. In order to solve this problem,this paper presents a multi-exposure fusion method for getting high quality images in high dynamic range scene. First,a set of multi-exposure images is obtained by multiple exposures in a same scene and their brightness condition is analyzed. Then,multi-exposure images under the same scene are decomposed using dual-tree complex wavelet transform( DT-CWT),and their low and high frequency components are obtained. Weight maps according to the brightness condition are assigned to the low components for fusion. Maximizing the region Sum Modified-Laplacian( SML) is adopted for high-frequency components fusing. Finally,the fused image is acquired by subjecting the low and high frequency coefficients to inverse DT-CWT.Experimental results show that the proposed approach generates high quality results with uniform distributed brightness and rich details. The proposed method is efficient and robust in varies scenes.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11863004 and 11763006)the Jiangxi Provincial Key Laboratory of Fusion and Information Control, China (Grant No. 20171BCD40005)the Project of Scientific and Technological Innovation Base of Jiangxi Province, China (Grant No. 20203CCD46008)。
文摘The dispersion relation and damping rate of kinetic Alfvén waves(KAWs) in a deuterium-tritium fusion plasma with slowing-down distributed α-particles are investigated using the kinetic theory. The variations of wave frequency and damping rate with respect to the α concentration(n_(α)/n_(e)) and perpendicular wave number(k_(⊥)) are studied from a numerical way. The results show that the fluctuation of α concentration slightly affects the frequency and damping rate of KAWs at low n_(α)/n_(e). In addition, the frequency and the damping rate increase as the k_(⊥) and the background temperature Te increase. For comparison, the calculations are performed also in the case of α-particles following an equivalent Maxwellian distribution. For a given k_(⊥), the value of the frequency obtained in the slowing-down distribution case is smaller than that obtained in the Maxwellian distribution case. Conversely, the value of the damping rate obtained in the slowing-down distribution case is slightly larger than that obtained in the Maxwellian distribution case.
文摘A mixture of deuterium (D) and tritium (T) is the most likely fuel for laser-driven inertial confinement fusion (ICF) reactors and hence DD and DT are the fusion reactions that will fire these reactors in the future. Neutrons produced from the two reactions will escape from the burning plasma, in the reactor core, and they are the only products possible to be measured directly. DT/DD neutron ratio is crucial for evaluation of T/D fuel ratio, burn control, tritium cycle and alpha particle self-heating power. To measure this ratio experimentally, the neutron spectra of DD and DT reactions have to be measured separately and simultaneously under high neutron counting with sufficient statistics (typically within 10% error) in a very short time and these issues are mutually contradicted. That is why it is not plausible to measure this high priority ratio for reactor performance accurately. Precise calculations of the DT/DD neutron ratio are needed. Here, we introduce such calculations using a three dimensional (3-D) Monte Carlo code at energies up to 40 MeV (the predicted maximum ion acceleration energy with the available laser systems). In addition, the fusion power ratio of DD and DT reactions is calculated for the same energy range. The study indicates that for a mixture of 50% deuterium and 50% triton, with taking into account the reactions D(d,n)<sup>3</sup>He and T(d,n)<sup>4</sup>He, the optimum energy value for achieving the most efficient laser-driven ICF is 0.08 MeV.
基金Supported by the National Natural Science Foundation of China(No.61308099,61304032)
文摘Due to the existing limited dynamic range a camera cannot reveal all the details in a high-dynamic range scene. In order to solve this problem,this paper presents a multi-exposure fusion method for getting high quality images in high dynamic range scene. First,a set of multi-exposure images is obtained by multiple exposures in a same scene and their brightness condition is analyzed. Then,multi-exposure images under the same scene are decomposed using dual-tree complex wavelet transform( DT-CWT),and their low and high frequency components are obtained. Weight maps according to the brightness condition are assigned to the low components for fusion. Maximizing the region Sum Modified-Laplacian( SML) is adopted for high-frequency components fusing. Finally,the fused image is acquired by subjecting the low and high frequency coefficients to inverse DT-CWT.Experimental results show that the proposed approach generates high quality results with uniform distributed brightness and rich details. The proposed method is efficient and robust in varies scenes.
