A model for fast electron-driven high-density plasma is proposed to describe the effect of injected fast electrons on the temperature and inner pressure of the plasma in the fast heating process of the double-cone ign...A model for fast electron-driven high-density plasma is proposed to describe the effect of injected fast electrons on the temperature and inner pressure of the plasma in the fast heating process of the double-cone ignition(DCI)scheme.Due to the collision of the two low-density plasmas,the density and volume of the high-density plasma vary.Therefore,the ignition temperature and energy requirement of the high-density plasma vary at different moments,and the required energy for hot electrons to heat the plasma also changes.In practical experiments,the energy input of hot electrons needs to be considered.To reduce the energy input of hot electrons,the optimal moment and the shortest time for injecting hot electrons with minimum energy are analyzed.In this paper,it is proposed to inject hot electrons for a short time to heat the high-density plasma to a relatively high temperature.Then,the alpha particles with the high heating rate and PdV work heat the plasma to the ignition temperature,further reducing the energy required to inject hot electrons.The study of the injection time of fast electrons can reduce the energy requirement of fast electrons for the high-density plasma and increase the probability of successful ignition of the high-density plasma.展开更多
A helicon wave plasma source in a tube of ring permanent magnets(PMs)has been constructed to study the effect of the conflguration of the magnetic fleld with zero magnetic points on plasma parameters.This device also ...A helicon wave plasma source in a tube of ring permanent magnets(PMs)has been constructed to study the effect of the conflguration of the magnetic fleld with zero magnetic points on plasma parameters.This device also serves as an exploration platform for a simple,compact helicon wave plasma source adaptable to engineering applications.A small-diameter(26 mm)highdensity(~10^(18)m^(-3))blue core plasma is produced in~1 Pa argon by helicon RF(radiofrequency)discharge using a NagoyaⅢantenna under magnetic fleld(~2 k G)of compact ring PMs(length~204 mm).Operational parameters,i.e.RF power and neutral gas pressure are scanned and plasma density is measured by an RF compensated probe to explore the operating characteristics of the device.Iconic feature of a helicon discharge,such as blue core plasmas and E-H-W mode transitions are well observed in the device,despite the wavelength calculated using the conventional dispersion relation of a bounded whistler waves(Chen 1991 Plasma Phys.Control.Fusion 33339)is order of magnitudes longer than the length of the plasma in this device which seems to suggest that such helicon device is impossible.Surprisingly,the wavelength calculated by the unbounded whistle wave dispersion formula in turn suggests the occurrence of a half wavelength resonance.展开更多
Effect of the injected plasma on the effective radius of the magnetic bubble in plasma sail is discussed. Results from solving both the two-dimensional magneto-hydrodynamic（MHD） equations and the magnetic flux conse...Effect of the injected plasma on the effective radius of the magnetic bubble in plasma sail is discussed. Results from solving both the two-dimensional magneto-hydrodynamic（MHD） equations and the magnetic flux conservation equation indicate that the effective radius of the magnetic bubble formed by the pure dipole field is very small, and the rate of the falloff of the magnetic field can be effectively reduced by the inflation of the high-density plasma. The falloff rate of the magnetic field can be r^-1.4. The effective radius of the magnetic bubble can hence be 8.2 km. The effective radius of the magnetic bubble increases about thirty-six times, comparing to the case of the pure dipole field.展开更多
脉冲高能量密度等离子体(pu lsed h igh energy density p lasm a,PHEDP)是一项新的材料表面改性技术.它集高电子温度、高能量密度、高定向速度于一身,在制备薄膜时具有沉积薄膜的温度低、沉积效率高、能量利用率高的优点,并兼具表面溅...脉冲高能量密度等离子体(pu lsed h igh energy density p lasm a,PHEDP)是一项新的材料表面改性技术.它集高电子温度、高能量密度、高定向速度于一身,在制备薄膜时具有沉积薄膜的温度低、沉积效率高、能量利用率高的优点,并兼具表面溅射、离子注入、冲击波和强淬火效应等综合效应;它可以制备纳米晶或非晶硬质薄膜,提高基底材料的表面硬度和耐磨、耐蚀性能;能够实现非金属材料表面金属化,所制备薄膜与基底之间存在很宽的混合过渡区,因此膜/基结合良好.文章主要介绍了作者近年来在该领域的部分研究成果,简要介绍了脉冲高能量密度等离子体的原理、特点及应用.分析了脉冲等离子体与材料相互作用的基本物理现象.展开更多
Aligned carbon nanotubes (CNTs) were prepared on Ni-coated Ni substrate by microwave plasma chemical vapor deposition (MWPCVD) with a mixture of methane and hydrogen gases at temperature of 550℃.The experimental resu...Aligned carbon nanotubes (CNTs) were prepared on Ni-coated Ni substrate by microwave plasma chemical vapor deposition (MWPCVD) with a mixture of methane and hydrogen gases at temperature of 550℃.The experimental results show a direct correlation between the alignment of CNTs and the density of the catalyst particles at low temperature.When the particle density is high enough,among CNTs there are strong interactions that can inhibit CNTs from growing randomly.The crowding effect among dense CNTs results in the aligned growth of CNTs at low temperature.展开更多
Recent research activities relevant to high energy density physics(HEDP) driven by the heavy ion beam at the Institute of Modern Physics, Chinese Academy of Sciences are presented. Radiography of static objects with t...Recent research activities relevant to high energy density physics(HEDP) driven by the heavy ion beam at the Institute of Modern Physics, Chinese Academy of Sciences are presented. Radiography of static objects with the fast extracted high energy carbon ion beam from the Cooling Storage Ring is discussed. Investigation of the low energy heavy ion beam and plasma interaction is reported. With HEDP research as one of the main goals, the project HIAF(High Intensity heavy-ion Accelerator Facility), proposed by the Institute of Modern Physics as the 12 th five-year-plan of China, is introduced.展开更多
Reactive ion etching is the interaction of reactive plasmas with surfaces. To obtain a detailed understanding of this process, significant properties of reactive composite low-pressure plasmas driven by electron cyclo...Reactive ion etching is the interaction of reactive plasmas with surfaces. To obtain a detailed understanding of this process, significant properties of reactive composite low-pressure plasmas driven by electron cyclotron resonance（ECR） were investigated and compared with the radial uniformity of the etch rate. The determination of the electronic properties of chlorine-and hydrogen-containing plasmas enabled the understanding of the pressure-dependent behavior of the plasma density and provided better insights into the electronic parameters of reactive etch gases. From the electrical evaluation of I（V） characteristics obtained using a Langmuir probe,plasmas of different compositions were investigated. The standard method of Druyvesteyn to derive the electron energy distribution functions by the second derivative of the I（V）characteristics was replaced by a mathematical model which has been evolved to be more robust against noise, mainly, because the first derivative of the I（V） characteristics is used. Special attention was given to the power of the energy dependence in the exponent. In particular, for plasmas that are generated by ECR with EM modes, the existence of Maxwellian distribution functions is not to be taken as a self-evident fact, but the bi-Maxwellian distribution was proven for Ar-and Kr-stabilized plasmas. In addition to the electron temperature, the global uniform discharge model has been shown to be useful for calculating the neutral gas temperature. To what extent the invasive method of using a Langmuir probe could be replaced with the noninvasive optical method of emission spectroscopy, particularly actinometry, was investigated,and the resulting data exhibited the same relative behavior as the Langmuir data. The correlation with etchrate data reveals the large chemical part of the removal process—most striking when the data is compared with etching in pure argon. Although the relative amount of the radial variation of plasma density and etch rate is approximately ？5%, the e展开更多
基金Project supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA_(2)5051000)the National Key R&D Program of China(Grant No.2023YFA1608400)+1 种基金the National Natural Science Foundation of China(Grant No.12005008)the Natural Science Foundation of Top Talent of SZTU(Grant No.GDRC202209).
文摘A model for fast electron-driven high-density plasma is proposed to describe the effect of injected fast electrons on the temperature and inner pressure of the plasma in the fast heating process of the double-cone ignition(DCI)scheme.Due to the collision of the two low-density plasmas,the density and volume of the high-density plasma vary.Therefore,the ignition temperature and energy requirement of the high-density plasma vary at different moments,and the required energy for hot electrons to heat the plasma also changes.In practical experiments,the energy input of hot electrons needs to be considered.To reduce the energy input of hot electrons,the optimal moment and the shortest time for injecting hot electrons with minimum energy are analyzed.In this paper,it is proposed to inject hot electrons for a short time to heat the high-density plasma to a relatively high temperature.Then,the alpha particles with the high heating rate and PdV work heat the plasma to the ignition temperature,further reducing the energy required to inject hot electrons.The study of the injection time of fast electrons can reduce the energy requirement of fast electrons for the high-density plasma and increase the probability of successful ignition of the high-density plasma.
基金supported by National Natural Science Foundation of China(No.U19A20113)。
文摘A helicon wave plasma source in a tube of ring permanent magnets(PMs)has been constructed to study the effect of the conflguration of the magnetic fleld with zero magnetic points on plasma parameters.This device also serves as an exploration platform for a simple,compact helicon wave plasma source adaptable to engineering applications.A small-diameter(26 mm)highdensity(~10^(18)m^(-3))blue core plasma is produced in~1 Pa argon by helicon RF(radiofrequency)discharge using a NagoyaⅢantenna under magnetic fleld(~2 k G)of compact ring PMs(length~204 mm).Operational parameters,i.e.RF power and neutral gas pressure are scanned and plasma density is measured by an RF compensated probe to explore the operating characteristics of the device.Iconic feature of a helicon discharge,such as blue core plasmas and E-H-W mode transitions are well observed in the device,despite the wavelength calculated using the conventional dispersion relation of a bounded whistler waves(Chen 1991 Plasma Phys.Control.Fusion 33339)is order of magnitudes longer than the length of the plasma in this device which seems to suggest that such helicon device is impossible.Surprisingly,the wavelength calculated by the unbounded whistle wave dispersion formula in turn suggests the occurrence of a half wavelength resonance.
基金supported by National Natural Science Foundation of China (No. 10975136)
文摘Effect of the injected plasma on the effective radius of the magnetic bubble in plasma sail is discussed. Results from solving both the two-dimensional magneto-hydrodynamic（MHD） equations and the magnetic flux conservation equation indicate that the effective radius of the magnetic bubble formed by the pure dipole field is very small, and the rate of the falloff of the magnetic field can be effectively reduced by the inflation of the high-density plasma. The falloff rate of the magnetic field can be r^-1.4. The effective radius of the magnetic bubble can hence be 8.2 km. The effective radius of the magnetic bubble increases about thirty-six times, comparing to the case of the pure dipole field.
文摘脉冲高能量密度等离子体(pu lsed h igh energy density p lasm a,PHEDP)是一项新的材料表面改性技术.它集高电子温度、高能量密度、高定向速度于一身,在制备薄膜时具有沉积薄膜的温度低、沉积效率高、能量利用率高的优点,并兼具表面溅射、离子注入、冲击波和强淬火效应等综合效应;它可以制备纳米晶或非晶硬质薄膜,提高基底材料的表面硬度和耐磨、耐蚀性能;能够实现非金属材料表面金属化,所制备薄膜与基底之间存在很宽的混合过渡区,因此膜/基结合良好.文章主要介绍了作者近年来在该领域的部分研究成果,简要介绍了脉冲高能量密度等离子体的原理、特点及应用.分析了脉冲等离子体与材料相互作用的基本物理现象.
文摘Aligned carbon nanotubes (CNTs) were prepared on Ni-coated Ni substrate by microwave plasma chemical vapor deposition (MWPCVD) with a mixture of methane and hydrogen gases at temperature of 550℃.The experimental results show a direct correlation between the alignment of CNTs and the density of the catalyst particles at low temperature.When the particle density is high enough,among CNTs there are strong interactions that can inhibit CNTs from growing randomly.The crowding effect among dense CNTs results in the aligned growth of CNTs at low temperature.
基金supported by the Major State Basic Research Development Program of China (‘973’ Program, grant number 2010CB832902)the National Natural Science Foundation of China (grant numbers 11105192, 11075192, 11275241, 11375034, and 11275238)
文摘Recent research activities relevant to high energy density physics(HEDP) driven by the heavy ion beam at the Institute of Modern Physics, Chinese Academy of Sciences are presented. Radiography of static objects with the fast extracted high energy carbon ion beam from the Cooling Storage Ring is discussed. Investigation of the low energy heavy ion beam and plasma interaction is reported. With HEDP research as one of the main goals, the project HIAF(High Intensity heavy-ion Accelerator Facility), proposed by the Institute of Modern Physics as the 12 th five-year-plan of China, is introduced.
基金the support of Deutsche Forschungsgemeinschaft,DFG#FR 1553/6-1
文摘Reactive ion etching is the interaction of reactive plasmas with surfaces. To obtain a detailed understanding of this process, significant properties of reactive composite low-pressure plasmas driven by electron cyclotron resonance（ECR） were investigated and compared with the radial uniformity of the etch rate. The determination of the electronic properties of chlorine-and hydrogen-containing plasmas enabled the understanding of the pressure-dependent behavior of the plasma density and provided better insights into the electronic parameters of reactive etch gases. From the electrical evaluation of I（V） characteristics obtained using a Langmuir probe,plasmas of different compositions were investigated. The standard method of Druyvesteyn to derive the electron energy distribution functions by the second derivative of the I（V）characteristics was replaced by a mathematical model which has been evolved to be more robust against noise, mainly, because the first derivative of the I（V） characteristics is used. Special attention was given to the power of the energy dependence in the exponent. In particular, for plasmas that are generated by ECR with EM modes, the existence of Maxwellian distribution functions is not to be taken as a self-evident fact, but the bi-Maxwellian distribution was proven for Ar-and Kr-stabilized plasmas. In addition to the electron temperature, the global uniform discharge model has been shown to be useful for calculating the neutral gas temperature. To what extent the invasive method of using a Langmuir probe could be replaced with the noninvasive optical method of emission spectroscopy, particularly actinometry, was investigated,and the resulting data exhibited the same relative behavior as the Langmuir data. The correlation with etchrate data reveals the large chemical part of the removal process—most striking when the data is compared with etching in pure argon. Although the relative amount of the radial variation of plasma density and etch rate is approximately ？5%, the e
