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RSS2020 Vol. 32, No. 9
Recommend Articles
2020, 32: 092001.
doi: 10.11884/HPLPB202032.200174
2020, 32: 092002.
doi: 10.11884/HPLPB202032.200090
2020, 32: 092003.
doi: 10.11884/HPLPB202032.200123
Display Method:
2020,
32: 1-2.
2020,
32: 1-1.
2020,
32: 092001.
doi: 10.11884/HPLPB202032.200174
Abstract:
An ultra-short ultra-intense laser can excite high-amplitude electron plasma waves or so called laser wakefields when it propagates in under-dense gas plasma. A laser wakefield accelerator makes use of such waves to accelerate charged particles (especially electrons and positrons). These plasma waves can sustain longitudinal acceleration fields over three orders of magnitude higher than conventional radio frequency accelerators. This new type of laser-driven plasma-based accelerator opens the way for compact particle accelerators and radiation sources. It also has the potential to be applied for the construction of future ultra-high energy TeV electron-positron colliders and free electron lasers. In this paper, the principle, characteristics and development history of this new accelerator, especially the main progress in the past ten years, the future development trend and the main challenges will be briefly reviewed and introduced.
An ultra-short ultra-intense laser can excite high-amplitude electron plasma waves or so called laser wakefields when it propagates in under-dense gas plasma. A laser wakefield accelerator makes use of such waves to accelerate charged particles (especially electrons and positrons). These plasma waves can sustain longitudinal acceleration fields over three orders of magnitude higher than conventional radio frequency accelerators. This new type of laser-driven plasma-based accelerator opens the way for compact particle accelerators and radiation sources. It also has the potential to be applied for the construction of future ultra-high energy TeV electron-positron colliders and free electron lasers. In this paper, the principle, characteristics and development history of this new accelerator, especially the main progress in the past ten years, the future development trend and the main challenges will be briefly reviewed and introduced.
2020,
32: 092002.
doi: 10.11884/HPLPB202032.200090
Abstract:
Laser-driven ion acceleration is a frontier of laser plasma physics which has been developed in recent decades. Energetic ion beam generated in the interaction of laser and matter has unique properties such as high brilliance, compact size, ultra-short duration, and low emittance. These advantages are particularly suitable for many potential applications. This paper describes the main physical mechanism of ion acceleration driven by ultrashort laser. It reviews the progress of a series of laser-driven ion acceleration experiments. At last, it provides a brief introduction of several potential applications of laser-driven ion sources.
Laser-driven ion acceleration is a frontier of laser plasma physics which has been developed in recent decades. Energetic ion beam generated in the interaction of laser and matter has unique properties such as high brilliance, compact size, ultra-short duration, and low emittance. These advantages are particularly suitable for many potential applications. This paper describes the main physical mechanism of ion acceleration driven by ultrashort laser. It reviews the progress of a series of laser-driven ion acceleration experiments. At last, it provides a brief introduction of several potential applications of laser-driven ion sources.
2020,
32: 092003.
doi: 10.11884/HPLPB202032.200123
Abstract:
Laboratory astrophysics came into being with the advent of modern high-energy density physics research devices that can be used to create extreme physical conditions in the laboratory similar to those of certain celestial bodies or their surroundings, such as high-power lasers or pinch devices to generate extreme astrophysical plasma conditions. Such experimental conditions are unprecedented and correspond directly to many important and critical physical phenomena in astrophysics. They enable people to study the problems with astrophysical background in the laboratory in a close, active and controllable way. This paper introduces the latest progress in this field in recent years, and presents perspectives on future research directions.
Laboratory astrophysics came into being with the advent of modern high-energy density physics research devices that can be used to create extreme physical conditions in the laboratory similar to those of certain celestial bodies or their surroundings, such as high-power lasers or pinch devices to generate extreme astrophysical plasma conditions. Such experimental conditions are unprecedented and correspond directly to many important and critical physical phenomena in astrophysics. They enable people to study the problems with astrophysical background in the laboratory in a close, active and controllable way. This paper introduces the latest progress in this field in recent years, and presents perspectives on future research directions.
2020,
32: 092004.
doi: 10.11884/HPLPB202032.200130
Abstract:
Currently, laboratory created energy density of laser-driven inertial confinement fusion (ICF) is extremely close to that for ignition, while the divergence between experiment and simulation is increasing. One of the key issues is the lack of advanced knowledge of laser-hohlraum coupling process, which has shown the complexity of hohlraum environment. Optical Thomson scattering (OTS) becomes the standard technique for diagnosing the ICF hohlraum plasma parameters, due to its capability of providing unperturbed, local and precise measurement. The development of OTS in China is closely related with the Shenguang series laser facilities, on which most of the ICF experiments are carried out. In recent years, 4ω(263 nm) Thomson scattering technique has been set up on Shenguang-III prototype and 100 kJ-level laser facility, the corresponding results help the understanding of ICF physics. In the near future, several novel methods will be developed, for high-precision diagnostics of ICF ignition hohlraum plasmas and the research of new physical phenomena.
Currently, laboratory created energy density of laser-driven inertial confinement fusion (ICF) is extremely close to that for ignition, while the divergence between experiment and simulation is increasing. One of the key issues is the lack of advanced knowledge of laser-hohlraum coupling process, which has shown the complexity of hohlraum environment. Optical Thomson scattering (OTS) becomes the standard technique for diagnosing the ICF hohlraum plasma parameters, due to its capability of providing unperturbed, local and precise measurement. The development of OTS in China is closely related with the Shenguang series laser facilities, on which most of the ICF experiments are carried out. In recent years, 4ω(263 nm) Thomson scattering technique has been set up on Shenguang-III prototype and 100 kJ-level laser facility, the corresponding results help the understanding of ICF physics. In the near future, several novel methods will be developed, for high-precision diagnostics of ICF ignition hohlraum plasmas and the research of new physical phenomena.
2020,
32: 092005.
doi: 10.11884/HPLPB202032.200094
Abstract:
The fast Z-pinch can highly efficiently convert the electrical energy stored in the pulsed power generator to X-ray radiation, creating high temperature, high density and high pressure environments. Significant progress in Z-pinch driven inertial confinement fusion and high energy density physics have been achieved in the last two decades. This paper outlines researches in indirect radiation driven fusion and magnetically direct driven fusion briefly, and introduces recent works on the dynamic hohlraum and the relative radiation source experiments on the 7−8 MA facility in China. It reviews progress of several Z-pinch applications in high energy density physics, such as the radiation-material interaction, opacity, dynamic material, laboratory astrophysics, as well as other domains. The paper also expects futher researches and developments of Z-pinch driven fusion and the corresponding applications in high energy density physics in China.
The fast Z-pinch can highly efficiently convert the electrical energy stored in the pulsed power generator to X-ray radiation, creating high temperature, high density and high pressure environments. Significant progress in Z-pinch driven inertial confinement fusion and high energy density physics have been achieved in the last two decades. This paper outlines researches in indirect radiation driven fusion and magnetically direct driven fusion briefly, and introduces recent works on the dynamic hohlraum and the relative radiation source experiments on the 7−8 MA facility in China. It reviews progress of several Z-pinch applications in high energy density physics, such as the radiation-material interaction, opacity, dynamic material, laboratory astrophysics, as well as other domains. The paper also expects futher researches and developments of Z-pinch driven fusion and the corresponding applications in high energy density physics in China.
2020,
32: 092006.
doi: 10.11884/HPLPB202032.200121
Abstract:
With the establishment of high-power laser facilities and the development of precise measurement technology, the interaction between high-power lasers and solids has become an important path to generate warm dense matter in laboratories. The structural complexity, transients and non-equilibrium of warm dense matter have brought great challenges to theoretical modeling and experimental measurements. This paper systematically reviews the important advances in the experimental methods and theoretical simulation methods in laser-generating warm dense matter, analyzes the physical processes such as electron excitation dynamics, electron-ion energy relaxation, and ionic dynamics. It summarizes the experimental techniques and theoretical methods of state diagnosis of warm dense matter, and discusses the development trend of laser-generating warm dense matter.
With the establishment of high-power laser facilities and the development of precise measurement technology, the interaction between high-power lasers and solids has become an important path to generate warm dense matter in laboratories. The structural complexity, transients and non-equilibrium of warm dense matter have brought great challenges to theoretical modeling and experimental measurements. This paper systematically reviews the important advances in the experimental methods and theoretical simulation methods in laser-generating warm dense matter, analyzes the physical processes such as electron excitation dynamics, electron-ion energy relaxation, and ionic dynamics. It summarizes the experimental techniques and theoretical methods of state diagnosis of warm dense matter, and discusses the development trend of laser-generating warm dense matter.
2020,
32: 092007.
doi: 10.11884/HPLPB202032.200134
Abstract:
In the study of inertial confinement fusion physics, the characteristics, temporal and spatial evolution of kinetic effects at the plasma interfaces attract crucial interest recently because they can affect the laser energy deposition, laser plasma instabilities, radiation asymmetry and implosion performance. A successful design of inertial confinement fusion requires the accurate description of the temporal and spatial evolution of the kinetic effects at the plasma interfaces, which is also a very challenging and unresolved problem in high energy density physics. In this paper, we will review our recent researches on the kinetic effects and their influence on laser plasma instabilities and implosion performance: (1) Electrostatic field arisen in the hohlraum wall/ablator (or the low-density fill-gas) interpenetration region will result in efficient acceleration of high energy ions, which is a source of the low-mode asymmetry of the implosion capsule. (2) The mechanism for the electrostatic field generation and the anomalous mix in the interpenetration layer at the high-Z and low-Z plasma interface and its effects on the laser plasma instabilities. (3) Reconstruction of the spontaneous electric and magnetic fields through proton radiography.
In the study of inertial confinement fusion physics, the characteristics, temporal and spatial evolution of kinetic effects at the plasma interfaces attract crucial interest recently because they can affect the laser energy deposition, laser plasma instabilities, radiation asymmetry and implosion performance. A successful design of inertial confinement fusion requires the accurate description of the temporal and spatial evolution of the kinetic effects at the plasma interfaces, which is also a very challenging and unresolved problem in high energy density physics. In this paper, we will review our recent researches on the kinetic effects and their influence on laser plasma instabilities and implosion performance: (1) Electrostatic field arisen in the hohlraum wall/ablator (or the low-density fill-gas) interpenetration region will result in efficient acceleration of high energy ions, which is a source of the low-mode asymmetry of the implosion capsule. (2) The mechanism for the electrostatic field generation and the anomalous mix in the interpenetration layer at the high-Z and low-Z plasma interface and its effects on the laser plasma instabilities. (3) Reconstruction of the spontaneous electric and magnetic fields through proton radiography.
2020,
32: 092008.
doi: 10.11884/HPLPB202032.200139
Abstract:
In order to carry out scientific research on the properties of materials under extremely high pressure conditions, a series of laser-driven high pressure loading technology based on Hügoniot, quasi-isentropic compression and “shock+quasi-isentropic” composite thermodynamic path compression have been developed on 10 kJ-level laser facility. The practical high-pressure loading design method has been established and optimization research on planarity, cleanness of compression wave has been performed. High-pressure state generation capability in wide parameter area which covers from above 1011 Pa of quasi-isentropic compression to above 1012 Pa of Hügoniot compression has been implemented, which provides an important technical foundation for the study of the high-pressure state equation and phase transition dynamics on the laser device.
In order to carry out scientific research on the properties of materials under extremely high pressure conditions, a series of laser-driven high pressure loading technology based on Hügoniot, quasi-isentropic compression and “shock+quasi-isentropic” composite thermodynamic path compression have been developed on 10 kJ-level laser facility. The practical high-pressure loading design method has been established and optimization research on planarity, cleanness of compression wave has been performed. High-pressure state generation capability in wide parameter area which covers from above 1011 Pa of quasi-isentropic compression to above 1012 Pa of Hügoniot compression has been implemented, which provides an important technical foundation for the study of the high-pressure state equation and phase transition dynamics on the laser device.
2020,
32: 092009.
doi: 10.11884/HPLPB202032.200122
Abstract:
The nonlinear evolution of stimulated Brillouin scattering (SBS) in inhomogeneous flowing plasmas is self-consistently investigated by the Vlasov-Maxwell simulations. In the physical regime where ion trapping is dominant, simulations show that the evolution of SBS includes a linear convective stage and a nonlinear stage. In the linear stage, the reflectivity is in good agreement with the theoretical prediction from the Rosenbluth gain. In the nonlinear stage, the reflectivity shows a continuous increase and becomes much larger than the theoretical value. And the auto-resonant growing of ion acoustic wave (IAW) shows a nature of absolute instability, which can be explained as the compensation of the negative kinetic frequency shift from trapped ions and the detuning due to the flow velocity gradient. Methods using the incoherence in the pump waves to mitigate the enhanced SBS are proposed. The saturation of SBS by the decay to solitary turbulence of the IAW is demonstrated in the fluid dominant regime. The formation of solitary structures is due to the generation of harmonics of IAW.
The nonlinear evolution of stimulated Brillouin scattering (SBS) in inhomogeneous flowing plasmas is self-consistently investigated by the Vlasov-Maxwell simulations. In the physical regime where ion trapping is dominant, simulations show that the evolution of SBS includes a linear convective stage and a nonlinear stage. In the linear stage, the reflectivity is in good agreement with the theoretical prediction from the Rosenbluth gain. In the nonlinear stage, the reflectivity shows a continuous increase and becomes much larger than the theoretical value. And the auto-resonant growing of ion acoustic wave (IAW) shows a nature of absolute instability, which can be explained as the compensation of the negative kinetic frequency shift from trapped ions and the detuning due to the flow velocity gradient. Methods using the incoherence in the pump waves to mitigate the enhanced SBS are proposed. The saturation of SBS by the decay to solitary turbulence of the IAW is demonstrated in the fluid dominant regime. The formation of solitary structures is due to the generation of harmonics of IAW.
2020,
32: 092010.
doi: 10.11884/HPLPB202032.200111
Abstract:
For ignition and high fusion gain, it’s the key issue to achieve high implosion velocity in inertial confinement fusion. The important implosion dynamics quantities like implosion velocity and residual mass can be diagnosed by implosion ablated convergence measurement. The measured results will be used to modify the point design, optimizing the ablator materials, thickness and laser pulse profiles. In recent years, we demonstrated the conventional implosion ablated convergence measurement on Shenguang laser facilities with the slit imaging technique. The high spatial resolution monochromatic imaging technique based on the spherically bent crystal was developed and used for the implosion ablated convergence measurement. With the continuing improvements of the imaging system and the modification of the diagnostics, a high spatial resolution implosion trajectory diagnosis has been implemented. The implosion velocities are measured with high precision while the uncertainties are not greater than 2.1%.
For ignition and high fusion gain, it’s the key issue to achieve high implosion velocity in inertial confinement fusion. The important implosion dynamics quantities like implosion velocity and residual mass can be diagnosed by implosion ablated convergence measurement. The measured results will be used to modify the point design, optimizing the ablator materials, thickness and laser pulse profiles. In recent years, we demonstrated the conventional implosion ablated convergence measurement on Shenguang laser facilities with the slit imaging technique. The high spatial resolution monochromatic imaging technique based on the spherically bent crystal was developed and used for the implosion ablated convergence measurement. With the continuing improvements of the imaging system and the modification of the diagnostics, a high spatial resolution implosion trajectory diagnosis has been implemented. The implosion velocities are measured with high precision while the uncertainties are not greater than 2.1%.
