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Review Article|26 Article(s)
Collimated gamma rays from laser wakefield accelerated electrons
Minghua Li, Liming Chen, Dazhang Li, Kai Huang, Yifei Li, Yong Ma, Wenchao Yan, Mengze Tao, Junhao Tan, Zhengming Sheng, and Jie Zhang
Betatron radiation from laser wakefield accelerated electrons and X-rays scattered off a counter-propagating relativistic electron bunch are collimated and hold the potential to extend the energy range to hard X-ray or gamma ray band. The peak brightness of these incoherent radiations could reach the level of the brightest synchrotron light sources in the world due to their femtosecond pulse duration and source size down to a few micrometers. In this article, the principle and properties of these radiation sources are briefly reviewed and compared. Then we present our recent progress in betatron radiation enhancement in the perspective of both photon energy and photon number. The enhancement is triggered by using a clustering gas target, arousing a second injection of a fiercely oscillating electron bunch with large charge or stimulating a resonantly enhanced oscillation of the ionization injected electrons. By adopting these methods, bright photon source with energy over 100 keV is generated which would greatly impact applications such as nuclear physics, diagnostic radiology, laboratory astrophysics and high-energy density science. Betatron radiation from laser wakefield accelerated electrons and X-rays scattered off a counter-propagating relativistic electron bunch are collimated and hold the potential to extend the energy range to hard X-ray or gamma ray band. The peak brightness of these incoherent radiations could reach the level of the brightest synchrotron light sources in the world due to their femtosecond pulse duration and source size down to a few micrometers. In this article, the principle and properties of these radiation sources are briefly reviewed and compared. Then we present our recent progress in betatron radiation enhancement in the perspective of both photon energy and photon number. The enhancement is triggered by using a clustering gas target, arousing a second injection of a fiercely oscillating electron bunch with large charge or stimulating a resonantly enhanced oscillation of the ionization injected electrons. By adopting these methods, bright photon source with energy over 100 keV is generated which would greatly impact applications such as nuclear physics, diagnostic radiology, laboratory astrophysics and high-energy density science.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 4, 188 (2018)
Unraveling the surface chemistry processes in lithiated and boronized plasma material interfaces under extreme conditions
P.S. Krstic, J.P. Allain, F.J. Dominguez-Gutierrez, and F. Bedoya
The review of recent theoretical and experimental research on the complex surface chemistry processes that evolve from low-Z material conditioning on plasma-facing materials under extreme fusion plasma conditions is presented. A combination of multi-scale computational physics and chemistry modeling with real-time diagnosis of the plasma-material interface in tokamak fusion plasma edge is complemented by ex-vessel in-situ single-effect experimental facilities to unravel the evolving characteristics of low-Z components under irradiation. Effects of the lithium and boron coatings at carbon surfaces to the retention of deuterium and chemical sputtering of the plasma-facing surfaces are discussed in detail. The critical role of oxygen in the surface chemistry during hydrogen-fuel irradiation is found to drive the kinetics and dynamics of these surfaces as they interact with fusion edge plasma that ultimately could have profound effects on fusion plasma confinement behavior. Computational studies also extend in spatio-temporal scales not accessible by empirical means and therefore open the opportunity for a strategic approach at irradiation surface science studies that combined these powerful computational tools with in-vessel and ex-vessel in-situ diagnostics. The review of recent theoretical and experimental research on the complex surface chemistry processes that evolve from low-Z material conditioning on plasma-facing materials under extreme fusion plasma conditions is presented. A combination of multi-scale computational physics and chemistry modeling with real-time diagnosis of the plasma-material interface in tokamak fusion plasma edge is complemented by ex-vessel in-situ single-effect experimental facilities to unravel the evolving characteristics of low-Z components under irradiation. Effects of the lithium and boron coatings at carbon surfaces to the retention of deuterium and chemical sputtering of the plasma-facing surfaces are discussed in detail. The critical role of oxygen in the surface chemistry during hydrogen-fuel irradiation is found to drive the kinetics and dynamics of these surfaces as they interact with fusion edge plasma that ultimately could have profound effects on fusion plasma confinement behavior. Computational studies also extend in spatio-temporal scales not accessible by empirical means and therefore open the opportunity for a strategic approach at irradiation surface science studies that combined these powerful computational tools with in-vessel and ex-vessel in-situ diagnostics.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 4, 165 (2018)
Review of solid-state linear transformer driver technology
Weihua Jiang
This paper is a review of recent developments in solid-state linear transformer driver (SSLTD) for applications to pulsed power generation. It summarizes the technological advances reported by previous publications and interprets the experimental progresses. The application of solidstate LTDs has been proved to be an attractive approach to make compact and repetitive pulsed power generators that have been sought by a variety of industrial applications and scientific researches. Their advantages and disadvantages compared with their alternatives are reported and analyzed in this paper. Future technical trends of solid-state LTDs are also discussed. This paper is a review of recent developments in solid-state linear transformer driver (SSLTD) for applications to pulsed power generation. It summarizes the technological advances reported by previous publications and interprets the experimental progresses. The application of solidstate LTDs has been proved to be an attractive approach to make compact and repetitive pulsed power generators that have been sought by a variety of industrial applications and scientific researches. Their advantages and disadvantages compared with their alternatives are reported and analyzed in this paper. Future technical trends of solid-state LTDs are also discussed.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 4, 159 (2018)
Influence of structural factors on the strength properties of aluminum alloys under shock wave loading
S.V. Razorenov
The results of measurements of the strength characteristics - Hugoniot elastic limit and spall strength of aluminum and aluminum alloys in different structural states under shock wave loading are presented. Single-crystals and polycrystalline technical grade aluminum А1013 and aluminum alloys А2024, АА6063Т6, А1421, A7, А7075, А3003, A5083, АА1070 in the initial coarse-grained state and ultrafine-grained or nanocrystalline structural state were investigated. The refinement of the grain structure was carried out by different methods of severe plastic deformation such as Equal Chanel Angular Pressing, Dynamic Channel Angular Pressing, High-Pressure Torsion and Accumulative Roll- Bonding. The strength characteristics of shock-loaded samples in different structural states were obtained from the analysis of the evolution of the free surface velocity histories recorded by means of laser Doppler velocimeter VISAR. The strain rates before spall fracture of the samples were in the range of 104-105 s-1, the maximum pressure of shock compression did not exceed 7 GPa. The results of these studies clearly demonstrate the influence of structural factors on the resistance to high-rate deformation and dynamic fracture, and it is much less than under the static and quasi-static loading. The results of measurements of the strength characteristics - Hugoniot elastic limit and spall strength of aluminum and aluminum alloys in different structural states under shock wave loading are presented. Single-crystals and polycrystalline technical grade aluminum А1013 and aluminum alloys А2024, АА6063Т6, А1421, A7, А7075, А3003, A5083, АА1070 in the initial coarse-grained state and ultrafine-grained or nanocrystalline structural state were investigated. The refinement of the grain structure was carried out by different methods of severe plastic deformation such as Equal Chanel Angular Pressing, Dynamic Channel Angular Pressing, High-Pressure Torsion and Accumulative Roll- Bonding. The strength characteristics of shock-loaded samples in different structural states were obtained from the analysis of the evolution of the free surface velocity histories recorded by means of laser Doppler velocimeter VISAR. The strain rates before spall fracture of the samples were in the range of 104-105 s-1, the maximum pressure of shock compression did not exceed 7 GPa. The results of these studies clearly demonstrate the influence of structural factors on the resistance to high-rate deformation and dynamic fracture, and it is much less than under the static and quasi-static loading.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 4, 145 (2018)
Recent advance in high-pressure solid-state metathesis reactions
Li Lei, and Leilei Zhang
High-pressure solid-state metathesis (HPSSM) reaction is an effective route to novel metal nitrides. A recent advance in HPSSM reactions is presented for a number of examples, including 3d transition metal nitrides (ε-Fe3N, ε-Fe3_xCoxN, CrN, and Co4Nx), 4d transition metal nitrides (MoNx), and 5d transition metal nitrides (Re3N, WNx). Thermodynamic investigations based on density functional theory (DFT) calculations on several typical HPSSM reactions between metal oxides and boron nitride indicate that the pressure could reduce the reaction enthalpy DH. Highpressure confining environment thermodynamically favors an ion-exchange process between metal atom and boron atom, and successfully results in the formation of well-crystalized metal nitrides with potential applications. High-pressure solid-state metathesis (HPSSM) reaction is an effective route to novel metal nitrides. A recent advance in HPSSM reactions is presented for a number of examples, including 3d transition metal nitrides (ε-Fe3N, ε-Fe3_xCoxN, CrN, and Co4Nx), 4d transition metal nitrides (MoNx), and 5d transition metal nitrides (Re3N, WNx). Thermodynamic investigations based on density functional theory (DFT) calculations on several typical HPSSM reactions between metal oxides and boron nitride indicate that the pressure could reduce the reaction enthalpy DH. Highpressure confining environment thermodynamically favors an ion-exchange process between metal atom and boron atom, and successfully results in the formation of well-crystalized metal nitrides with potential applications.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 3, 95 (2018)
Relaxation of non-isothermal hot dense plasma parameters
S.K. Kodanova, M.K. Issanova, S.M. Amirov, T.S. Ramazanov, A. Tikhonov, and Zh.A. Moldabekov
The relaxation of temperature, coupling parameters, the excess part of equation of state, and the correlation energy of the non-isothermal hot dense plasmas are considered on the basis of the method of effective interaction potentials. The electroneion effective interaction potential for the hot dense plasma is discussed. The accuracy of description of the dense plasma properties by the effective electroneion interaction potential is demonstrated by the agreement of the derived quantities like stopping power and transport coefficients calculated using our methodology with the results of the finite-temperature Kohn-Sham density-functional theory molecular dynamics, and orbital-free molecular dynamics results as well as with the data obtained using other theoretical approaches. The relaxation of temperature, coupling parameters, the excess part of equation of state, and the correlation energy of the non-isothermal hot dense plasmas are considered on the basis of the method of effective interaction potentials. The electroneion effective interaction potential for the hot dense plasma is discussed. The accuracy of description of the dense plasma properties by the effective electroneion interaction potential is demonstrated by the agreement of the derived quantities like stopping power and transport coefficients calculated using our methodology with the results of the finite-temperature Kohn-Sham density-functional theory molecular dynamics, and orbital-free molecular dynamics results as well as with the data obtained using other theoretical approaches.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 1, 40 (2018)
Optimization of hole-boring radiation pressure acceleration of ion beams for fusion ignition
S.M. Weng, Z.M. Sheng, M. Murakami, M. Chen, M. Liu, H.C. Wang, T. Yuan, and J. Zhang
In contrast to ion beams produced by conventional accelerators, ion beams accelerated by ultrashort intense laser pulses have advantages of ultrashort bunch duration and ultrahigh density, which are achieved in compact size. However, it is still challenging to simultaneously enhance their quality and yield for practical applications such as fast ion ignition of inertial confinement fusion. Compared with other mechanisms of laser-driven ion acceleration, the hole-boring radiation pressure acceleration has a special advantage in generating high-fluence ion beams suitable for the creation of high energy density state of matters. In this paper, we present a review on some theoretical and numerical studies of the hole-boring radiation pressure acceleration. First we discuss the typical field structure associated with this mechanism, its intrinsic feature of oscillations, and the underling physics. Then we will review some recently proposed schemes to enhance the beam quality and the efficiency in the hole-boring radiation pressure acceleration, such as matching laser intensity profile with target density profile, and using two-ion-species targets. Based on this, we propose an integrated scheme for efficient high-quality hole-boring radiation pressure acceleration, in which the longitudinal density profile of a composite target as well as the laser transverse intensity profile are tailored according to the matching condition. In contrast to ion beams produced by conventional accelerators, ion beams accelerated by ultrashort intense laser pulses have advantages of ultrashort bunch duration and ultrahigh density, which are achieved in compact size. However, it is still challenging to simultaneously enhance their quality and yield for practical applications such as fast ion ignition of inertial confinement fusion. Compared with other mechanisms of laser-driven ion acceleration, the hole-boring radiation pressure acceleration has a special advantage in generating high-fluence ion beams suitable for the creation of high energy density state of matters. In this paper, we present a review on some theoretical and numerical studies of the hole-boring radiation pressure acceleration. First we discuss the typical field structure associated with this mechanism, its intrinsic feature of oscillations, and the underling physics. Then we will review some recently proposed schemes to enhance the beam quality and the efficiency in the hole-boring radiation pressure acceleration, such as matching laser intensity profile with target density profile, and using two-ion-species targets. Based on this, we propose an integrated scheme for efficient high-quality hole-boring radiation pressure acceleration, in which the longitudinal density profile of a composite target as well as the laser transverse intensity profile are tailored according to the matching condition.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 1, 28 (2018)
Progress in particle-beam-driven inertial fusion research: Activities in Japan
Kazuhiko Horioka
Research activities in Japan relevant to particle beam inertial fusion are briefly reviewed. These activities can be ascended to the 1980s.During the past three decades, significant progress in particle beam fusion, pulsed power systems, accelerator schemes for intense beams, targetphysics, and high-energy-density physics research has been made by a number of research groups at universities and accelerator facilities inJapan. High-flux ions have been extracted from laser ablation plasmas. Controllability of the ion velocity distribution in the plasma by an axialmagnetic and/or electric field has realized a stable high-flux low-emittance beam injector. Beam dynamics have been studied both theoreticallyand experimentally. The efforts have been concentrated on the beam behavior during the final compression stage of intense beam accelerators. Anovel accelerator scheme based on a repetitive induction modulator has been proposed as a cost-effective particle-beam driver scheme. Beamplasmainteraction and pulse-powered plasma experiments have been investigated as relevant studies of particle beam inertial fusion. Anirradiation method to mitigate the instability in imploding target has been proposed using oscillating heavy-ion beams. The new irradiationmethod has reopened the exploration of direct drive scheme of particle beam fusion. Research activities in Japan relevant to particle beam inertial fusion are briefly reviewed. These activities can be ascended to the 1980s.During the past three decades, significant progress in particle beam fusion, pulsed power systems, accelerator schemes for intense beams, targetphysics, and high-energy-density physics research has been made by a number of research groups at universities and accelerator facilities inJapan. High-flux ions have been extracted from laser ablation plasmas. Controllability of the ion velocity distribution in the plasma by an axialmagnetic and/or electric field has realized a stable high-flux low-emittance beam injector. Beam dynamics have been studied both theoreticallyand experimentally. The efforts have been concentrated on the beam behavior during the final compression stage of intense beam accelerators. Anovel accelerator scheme based on a repetitive induction modulator has been proposed as a cost-effective particle-beam driver scheme. Beamplasmainteraction and pulse-powered plasma experiments have been investigated as relevant studies of particle beam inertial fusion. Anirradiation method to mitigate the instability in imploding target has been proposed using oscillating heavy-ion beams. The new irradiationmethod has reopened the exploration of direct drive scheme of particle beam fusion.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 1, 12 (2018)
The pulsed high magnetic field facility and scientific research at Wuhan National High Magnetic Field Center
Xiaotao Han, Tao Peng, Hongfa Ding, Tonghai Ding, Zengwei Zhu, Zhengcai Xia, Junfeng Wang, Junbo Han, Zhongwen Ouyang, Zhenxing Wang, Yibo Han, Houxiu Xiao, Quanliang Cao, Yiliang Lv, Yuan Pan, and Liang Li
Wuhan National High Magnetic Field Center (WHMFC) at Huazhong University of Science and Technology is one of the top-class research centers in the world, which can offer pulsed fields up to 90.6 T with different field waveforms for scientific research and has passed the final evaluation of the Chinese government in 2014. This paper will give a brief introduction of the facility and the development status of pulsed magnetic fields research at WHMFC. In addition, it will describe the application development of pulsed magnetic fields in both scientific and industrial research. Wuhan National High Magnetic Field Center (WHMFC) at Huazhong University of Science and Technology is one of the top-class research centers in the world, which can offer pulsed fields up to 90.6 T with different field waveforms for scientific research and has passed the final evaluation of the Chinese government in 2014. This paper will give a brief introduction of the facility and the development status of pulsed magnetic fields research at WHMFC. In addition, it will describe the application development of pulsed magnetic fields in both scientific and industrial research.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2017
- Vol. 2, Issue 6, 278 (2017)
Formation of Field Reversed Configuration (FRC) on the Yingguang-I device
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As a hybrid approach to realizing fusion energy, Magnetized Target Fusion (MTF) based on the Field Reversed Configuration (FRC), which has the plasma density and confinement time in the range between magnetic and inertial confinement fusion, has been recently widely pursued around the world. To investigate the formation and confinement of the FRC plasma injector for MTF, the Yingguang-I, which is an FRC test device and contains a multi-bank program-discharged pulsed power sub-system, was constructed at the Institute of Fluid Physics (IFP), China. This paper presents the pulsed power components and their parameters of the device in detail, then gives a brief description of progress in experiments of FRC formation. Experimental results of the pulsed power sub-system show that the peak current/magnetic field of 110 kA/0.3 T, 10 kA/1.2 T and 1.7 MA/3.4 T were achieved in the bias, mirror and θ-pinch circuits with quarter cycle of 80 μs, 700 μs and 3.8 μs respectively. The induced electric field in the neutral gas was greater than 0.25 kV/cm when the ionization bank was charged to 70 kV. With H2 gas of 8 Pa, the plasma target of density 1016 cm-3, separatrix radius 4 cm, half-length 17 cm, equilibrium temperature 200 eV and lifetime 3 μs (approximately the half pulse width of the reversed field) have been obtained through the θ-pinch method when the bias, mirror, ionization and θ-pinch banks were charged to 5 kV, 5 kV, 55 kV and ±45 kV respectively. The images from the high-speed end-on framing camera demonstrate the formation processes of FRC and some features agree well with the results with the two-dimension magneto hydrodynamics code (2D-MHD). As a hybrid approach to realizing fusion energy, Magnetized Target Fusion (MTF) based on the Field Reversed Configuration (FRC), which has the plasma density and confinement time in the range between magnetic and inertial confinement fusion, has been recently widely pursued around the world. To investigate the formation and confinement of the FRC plasma injector for MTF, the Yingguang-I, which is an FRC test device and contains a multi-bank program-discharged pulsed power sub-system, was constructed at the Institute of Fluid Physics (IFP), China. This paper presents the pulsed power components and their parameters of the device in detail, then gives a brief description of progress in experiments of FRC formation. Experimental results of the pulsed power sub-system show that the peak current/magnetic field of 110 kA/0.3 T, 10 kA/1.2 T and 1.7 MA/3.4 T were achieved in the bias, mirror and θ-pinch circuits with quarter cycle of 80 μs, 700 μs and 3.8 μs respectively. The induced electric field in the neutral gas was greater than 0.25 kV/cm when the ionization bank was charged to 70 kV. With H2 gas of 8 Pa, the plasma target of density 1016 cm-3, separatrix radius 4 cm, half-length 17 cm, equilibrium temperature 200 eV and lifetime 3 μs (approximately the half pulse width of the reversed field) have been obtained through the θ-pinch method when the bias, mirror, ionization and θ-pinch banks were charged to 5 kV, 5 kV, 55 kV and ±45 kV respectively. The images from the high-speed end-on framing camera demonstrate the formation processes of FRC and some features agree well with the results with the two-dimension magneto hydrodynamics code (2D-MHD).
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2017
- Vol. 2, Issue 5, 263 (2017)
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