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Research Article|33 Article(s)
High energy and high brightness laser compton backscattering gamma-ray source at IHEP
Guang-Peng An, Yun-Long Chi, Yong-Le Dang, Guang-Yong Fu, Bing Guo, Yong-Sheng Huang, Chuang-Ye He, Xiang-Cheng Kong, Xiao-Fei Lan, Jia-Cai Li, Fu-Long Liu, Jin-Shui Shi, Xian-Jing Sun, Yi Wang, Jian-Li Wang, Lin Wang, Yuan-Yuan Wei, Gang Wu, Guang-Lei Xu, Xiao-Feng Xi, Guo-Jun Yang, Chun-Lei Zhang, Zhuo Zhang, Zhi-Peng Zheng, Xiao-Ding Zhang, and Shao-Ping Zhang
Based on the LINAC of BEPCII, a high-polarized, high bightness, energy-tunable, monoenergetic laser compton backscattering (LCS) gamma-ray source is under construction at IHEP. The gamma-ray energy range is from 1 MeV to 111 MeV. It is a powerful and hopeful research platform to reveal the underlying physics of the nuclear, the basic particles and the vacuum or to check the exist basic physical models, quantum electrodynamic (QED) theories. In the platform, a 1.064 mm Nd:YAG laser system and a 10.6 mm CO2 laser system are employed. All the trigger signals to the laser system and the electron control system are from the only reference clock at the very beginning of the LINAC to make sure the temporal synchronization. Two optical transition radiation (OTR) targets and two charged-couple devices (CCD) are used to monitor and to align the electron beam and the laser beam. With the LCS gamma-ray source, it is proposed to experimentally check the gamma-ray calibrations, the photon-nuclear physics, nuclear astrophysics and some basic QED phenomena. Based on the LINAC of BEPCII, a high-polarized, high bightness, energy-tunable, monoenergetic laser compton backscattering (LCS) gamma-ray source is under construction at IHEP. The gamma-ray energy range is from 1 MeV to 111 MeV. It is a powerful and hopeful research platform to reveal the underlying physics of the nuclear, the basic particles and the vacuum or to check the exist basic physical models, quantum electrodynamic (QED) theories. In the platform, a 1.064 mm Nd:YAG laser system and a 10.6 mm CO2 laser system are employed. All the trigger signals to the laser system and the electron control system are from the only reference clock at the very beginning of the LINAC to make sure the temporal synchronization. Two optical transition radiation (OTR) targets and two charged-couple devices (CCD) are used to monitor and to align the electron beam and the laser beam. With the LCS gamma-ray source, it is proposed to experimentally check the gamma-ray calibrations, the photon-nuclear physics, nuclear astrophysics and some basic QED phenomena.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 4, 219 (2018)
The Richtmyer-Meshkov instability of a double-layer interface in convergent geometry with magnetohydrodynamics
Yuan Li, Ravi Samtaney, and Vincent Wheatley
The interaction between a converging cylindrical shock and double density interfaces in the presence of a saddle magnetic field is numerically investigated within the framework of ideal magnetohydrodynamics. Three fluids of differing densities are initially separated by the two perturbed cylindrical interfaces. The initial incident converging shock is generated from a Riemann problem upstream of the first interface. The effect of the magnetic field on the instabilities is studied through varying the field strength. It shows that the Richtmyer-Meshkov and Rayleigh-Taylor instabilities are mitigated by the field, however, the extent of the suppression varies on the interface which leads to nonaxisymmetric growth of the perturbations. The degree of asymmetry of the interfacial growth rate is increased when the seed field strength is increased. The interaction between a converging cylindrical shock and double density interfaces in the presence of a saddle magnetic field is numerically investigated within the framework of ideal magnetohydrodynamics. Three fluids of differing densities are initially separated by the two perturbed cylindrical interfaces. The initial incident converging shock is generated from a Riemann problem upstream of the first interface. The effect of the magnetic field on the instabilities is studied through varying the field strength. It shows that the Richtmyer-Meshkov and Rayleigh-Taylor instabilities are mitigated by the field, however, the extent of the suppression varies on the interface which leads to nonaxisymmetric growth of the perturbations. The degree of asymmetry of the interfacial growth rate is increased when the seed field strength is increased.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 4, 207 (2018)
Development of new diagnostics based on LiF detector for pump-probe experiments
T. Pikuz, A. Faenov, N. Ozaki, T. Matsuoka, B. Albertazzi, N.J. Hartley, K. Miyanishi, K. Katagiri, S. Matsuyama, K. Yamauchi, H. Habara, Y. Inubushi, T. Togashi, H. Yumoto, H. Ohashi, Y. Tange, T. Yabuuchi, M. Yabashi, A.N. Grum-Grzhimailo, A. Casner, I. Skobelev, S. Makarov, S. Pikuz, G. Rigon, M. Koenig, K.A. Tanaka, T. Ishikawa, and R. Kodama
We present new diagnostics for use in optical laser pump - X-ray Free Electron Laser (XFEL) probe experiments to monitor dimensions, intensity profile and focusability of the XFEL beam and to control initial quality and homogeneity of targets to be driven by optical laser pulse. By developing X-ray imaging, based on the use of an LiF crystal detector, we were able to measure the distribution of energy inside a hard X-ray beam with unprecedented high spatial resolution (~1 mm) and across a field of view larger than some millimetres. This diagnostic can be used in situ, provides a very high dynamic range, has an extremely limited cost, and is relatively easy to be implemented in pumpprobe experiments. The proposed methods were successfully applied in pump-probe experiments at the SPring-8 Angstrom Compact free electron LAser (SACLA) XFEL facility and its potential was demonstrated for current and future High Energy Density Science experiments. We present new diagnostics for use in optical laser pump - X-ray Free Electron Laser (XFEL) probe experiments to monitor dimensions, intensity profile and focusability of the XFEL beam and to control initial quality and homogeneity of targets to be driven by optical laser pulse. By developing X-ray imaging, based on the use of an LiF crystal detector, we were able to measure the distribution of energy inside a hard X-ray beam with unprecedented high spatial resolution (~1 mm) and across a field of view larger than some millimetres. This diagnostic can be used in situ, provides a very high dynamic range, has an extremely limited cost, and is relatively easy to be implemented in pumpprobe experiments. The proposed methods were successfully applied in pump-probe experiments at the SPring-8 Angstrom Compact free electron LAser (SACLA) XFEL facility and its potential was demonstrated for current and future High Energy Density Science experiments.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 4, 197 (2018)
Recent progress in ICF target fabrication at RCLF
Kai Du, Meifang Liu, Tao Wang, Xiaoshan He, Zongwei Wang, and Juan Zhang
Target is one of the essential parts in inertial confinement fusion (ICF) experiments. To ensure the symmetry and hydrodynamic stability in the implosion, there are stringent specifications for the target. Driven by the need to fabricate the target required by ICF experiments, a series of target fabrication techniques, including capsule fabrication techniques and the techniques of target characterization and assembly, are developed by the Research Center of Laser Fusion (RCLF), China Academy of Engineering Physics (CAEP). The capsule fabrication techniques for preparing polymer shells, glow discharge polymer (GDP) shells and hollow glass micro-sphere (HGM) are studied, and the techniques of target characterization and assembly are also investigated in this paper. Fundamental research about the target fabrication is also done to improve the quality of the target. Based on the development of target fabrication techniques, some kinds of target have been prepared and applied in the ICF experiments. Target is one of the essential parts in inertial confinement fusion (ICF) experiments. To ensure the symmetry and hydrodynamic stability in the implosion, there are stringent specifications for the target. Driven by the need to fabricate the target required by ICF experiments, a series of target fabrication techniques, including capsule fabrication techniques and the techniques of target characterization and assembly, are developed by the Research Center of Laser Fusion (RCLF), China Academy of Engineering Physics (CAEP). The capsule fabrication techniques for preparing polymer shells, glow discharge polymer (GDP) shells and hollow glass micro-sphere (HGM) are studied, and the techniques of target characterization and assembly are also investigated in this paper. Fundamental research about the target fabrication is also done to improve the quality of the target. Based on the development of target fabrication techniques, some kinds of target have been prepared and applied in the ICF experiments.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 3, 135 (2018)
Self-modulation and anomalous collective scattering of laser produced intense ion beam in plasmas
K. Mima, J. Fuchs, T. Taguchi, J. Alvarez, J.R. Marques, S.N. Chen, T. Tajima, and J.M. Perlado
The collective interaction between intense ion beams and plasmas is studied by simulations and experiments, where an intense proton beam produced by a short pulse laser is injected into a pre-ionized gas. It is found that, depending on its current density, collective effects can significantly alter the propagated ion beam and the stopping power. The quantitative agreement that is found between theories and experiments constitutes the first validation of the collective interaction theory. The effects in the interaction between intense ion beams and background gas plasmas are of importance for the design of laser fusion reactors as well as for beam physics. The collective interaction between intense ion beams and plasmas is studied by simulations and experiments, where an intense proton beam produced by a short pulse laser is injected into a pre-ionized gas. It is found that, depending on its current density, collective effects can significantly alter the propagated ion beam and the stopping power. The quantitative agreement that is found between theories and experiments constitutes the first validation of the collective interaction theory. The effects in the interaction between intense ion beams and background gas plasmas are of importance for the design of laser fusion reactors as well as for beam physics.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 3, 127 (2018)
Macroscopic laser-plasma interaction under strong non-local transport conditions for coupled matter and radiation
J. Nikl, M. Holec, M. Zeman, M. Kucharík, J. Limpouch, and S. Weber
Reliable simulations of laseretarget interaction on the macroscopic scale are burdened by the fact that the energy transport is very often nonlocal. This means that the mean-free-path of the transported species is larger than the local gradient scale lengths and transport can be no longer considered diffusive. Kinetic simulations are not a feasible option due to tremendous computational demands, limited validity of the collisional operators and inaccurate treatment of thermal radiation. This is the point where hydrodynamic codes with non-local radiation and electron heat transport based on first principles emerge. The simulation code PETE (Plasma Euler and Transport Equations) combines both of them with a laser absorption method based on the Helmholtz equation and a radiation diffusion scheme presented in this article. In the case of modelling ablation processes it can be observed that both, thermal and radiative, transport processes are strongly non-local for laser intensities of 1013 W=cm2 and above. In this paper simulations for various laser intensities and different ablator materials are presented, where the non-local and diffusive treatments of radiation transport are compared. Significant discrepancies are observed, supporting importance of non-local transport for inertial confinement fusion related studies as well as for pre-pulse generated plasma in ultra-high intensity laseretarget interaction.The authors acknowledge support from the project High Field Initiative (HiFI) (CZ.02.1.01/0.0/0.0/15_003/0000449) and ELI Tools for Advanced Simulation (ELITAS) (CZ.02.1.01/0.0/0.0/16_013/0001793), both from European Regional Development Fund, the Czech Science Foundation project 18-20962S and Czech Technical University grant SGS16/247/OHK4/3T/14. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement number 633053 (EUROfusion project CfP-AWP17-IFE-CEA-01). Reliable simulations of laseretarget interaction on the macroscopic scale are burdened by the fact that the energy transport is very often nonlocal. This means that the mean-free-path of the transported species is larger than the local gradient scale lengths and transport can be no longer considered diffusive. Kinetic simulations are not a feasible option due to tremendous computational demands, limited validity of the collisional operators and inaccurate treatment of thermal radiation. This is the point where hydrodynamic codes with non-local radiation and electron heat transport based on first principles emerge. The simulation code PETE (Plasma Euler and Transport Equations) combines both of them with a laser absorption method based on the Helmholtz equation and a radiation diffusion scheme presented in this article. In the case of modelling ablation processes it can be observed that both, thermal and radiative, transport processes are strongly non-local for laser intensities of 1013 W=cm2 and above. In this paper simulations for various laser intensities and different ablator materials are presented, where the non-local and diffusive treatments of radiation transport are compared. Significant discrepancies are observed, supporting importance of non-local transport for inertial confinement fusion related studies as well as for pre-pulse generated plasma in ultra-high intensity laseretarget interaction.The authors acknowledge support from the project High Field Initiative (HiFI) (CZ.02.1.01/0.0/0.0/15_003/0000449) and ELI Tools for Advanced Simulation (ELITAS) (CZ.02.1.01/0.0/0.0/16_013/0001793), both from European Regional Development Fund, the Czech Science Foundation project 18-20962S and Czech Technical University grant SGS16/247/OHK4/3T/14. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement number 633053 (EUROfusion project CfP-AWP17-IFE-CEA-01).
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 3, 110 (2018)
A novel superconducting magnetic levitation method to support the laser fusion capsule by using permanent magnets
Xiaojia Li, Tingting Xiao, Fengwei Chen, Yingjuan Zhang, Xiaofei Li, and Weidong Wu
A novel magnetic levitation support method is proposed, which can relieve the perturbation caused by traditional support methods and provide more accurate position control of the capsule. This method can keep the perfect symmetry of the octahedral spherical hohlraum and has the characteristics in stability, tunability and simplicity. It is also favorable that all the results, such as supporting forces acting on the superconducting capsule, are calculated analytically, and numerical simulations are performed to verify these results. A typical realistic design is proposed and discussed in detail. The superconducting coating material is suggested, and the required superconducting properties are listed. Damped oscillation of the floating capsule in thin helium gas is discussed, and the restoring time is estimated. A novel magnetic levitation support method is proposed, which can relieve the perturbation caused by traditional support methods and provide more accurate position control of the capsule. This method can keep the perfect symmetry of the octahedral spherical hohlraum and has the characteristics in stability, tunability and simplicity. It is also favorable that all the results, such as supporting forces acting on the superconducting capsule, are calculated analytically, and numerical simulations are performed to verify these results. A typical realistic design is proposed and discussed in detail. The superconducting coating material is suggested, and the required superconducting properties are listed. Damped oscillation of the floating capsule in thin helium gas is discussed, and the restoring time is estimated.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 3, 104 (2018)
Warm dense matter research at HIAF
Rui Cheng, Yu Lei, Xianming Zhou, Yuyu Wang, Yanhong Chen, Yongtao Zhao, Jieru Ren, Lina Sheng, Jiancheng Yang, Zimin Zhang, Yingchao Du, Wei Gai, Xinwen Ma, and Guoqing Xiao
The research activities on warm dense matter driven by intense heavy ion beams at the new project High Intensity heavy-ion Accelerator Facility (HIAF) are presented. The ion beam parameters and the simulated accessible state of matter at HIAF are introduced, respectively. The progresses of the developed diagnostics for warm dense matter research including high energy electron radiography, multiple-channel pyrometer, in-situ energy loss and charge state of ion detector are briefly introduced. The research activities on warm dense matter driven by intense heavy ion beams at the new project High Intensity heavy-ion Accelerator Facility (HIAF) are presented. The ion beam parameters and the simulated accessible state of matter at HIAF are introduced, respectively. The progresses of the developed diagnostics for warm dense matter research including high energy electron radiography, multiple-channel pyrometer, in-situ energy loss and charge state of ion detector are briefly introduced.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 2, 85 (2018)
Optimizing beam transport in rapidly compressing beams on the neutralized drift compression experiment - II
Anton D. Stepanov, John J. Barnard, Alex Friedman, Erik P. Gilson, David P. Grote, Qing Ji, Igor D. Kaganovich, Arun Persaud, Peter A. Seidl, and Thomas Schenkel
The Neutralized Drift Compression Experiment-II (NDCX-II) is an induction linac that generates intense pulses of 1.2 MeV helium ions for heating matter to extreme conditions. Here, we present recent results on optimizing beam transport. The NDCX-II beamline includes a 1-m-long drift section downstream of the last transport solenoid, which is filled with charge-neutralizing plasma that enables rapid longitudinal compression of an intense ion beam against space-charge forces. The transport section on NDCX-II consists of 28 solenoids. Finding optimal field settings for a group of solenoids requires knowledge of the envelope parameters of the beam. Imaging the beam on the scintillator gives the radius of the beam, but the envelope angle is not measured directly. We demonstrate how the parameters of the beam envelope (radius, envelop angle, and emittance) can be reconstructed from a series of images taken by varying the B-field strengths of a solenoid upstream of the scintillator. We use this technique to evaluate emittance at several points in the NDCX-II beamline and for optimizing the trajectory of the beam at the entry of the plasma-filled drift section. The Neutralized Drift Compression Experiment-II (NDCX-II) is an induction linac that generates intense pulses of 1.2 MeV helium ions for heating matter to extreme conditions. Here, we present recent results on optimizing beam transport. The NDCX-II beamline includes a 1-m-long drift section downstream of the last transport solenoid, which is filled with charge-neutralizing plasma that enables rapid longitudinal compression of an intense ion beam against space-charge forces. The transport section on NDCX-II consists of 28 solenoids. Finding optimal field settings for a group of solenoids requires knowledge of the envelope parameters of the beam. Imaging the beam on the scintillator gives the radius of the beam, but the envelope angle is not measured directly. We demonstrate how the parameters of the beam envelope (radius, envelop angle, and emittance) can be reconstructed from a series of images taken by varying the B-field strengths of a solenoid upstream of the scintillator. We use this technique to evaluate emittance at several points in the NDCX-II beamline and for optimizing the trajectory of the beam at the entry of the plasma-filled drift section.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 2, 78 (2018)
Review of stopping power and Coulomb explosion for molecular ion in plasmas
Guiqiu Wang, He Yi, Yujiao Li, Yaochuan Wang, Dajun Liu, Fei Gao, Wei Liu, Jieru Ren, Xing Wang, Yongtao Zhao, and Younian Wang
We summarize our theoretical studies for stopping power of energetic heavy ion, diatomic molecular ions and small clusters penetrating through plasmas. As a relevant research field for the heavy ion inertial confinement fusion (HICF), we lay the emphasis on the dynamic polarization and correlation effects of the constituent ion within the molecular ion and cluster for stopping power in order to disclose the role of the vicinage effect on the Coulomb explosion and energy deposition of molecules and clusters in plasma. On the other hand, as a promising scheme for ICF, both a strong laser field and an intense ion beam are used to irradiate a plasma target. So the influence of a strong laser field on stopping power is significant. We discussed a large range of laser and plasma parameters on the coulomb explosion and stopping power for correlated-ion cluster and C60 cluster. Furthermore, in order to indicate the effects of different cluster types and sizes on the stopping power, a comparison is made for hydrogen and carbon clusters. In addition, the deflection of molecular axis for diatomic molecules during the Coulomb explosion is also given for the cases both in the presence of a laser field and laser free. Finally, a future experimental scheme is put forward to measure molecular ion stopping power in plasmas in Xi’an Jiaotong University of China. We summarize our theoretical studies for stopping power of energetic heavy ion, diatomic molecular ions and small clusters penetrating through plasmas. As a relevant research field for the heavy ion inertial confinement fusion (HICF), we lay the emphasis on the dynamic polarization and correlation effects of the constituent ion within the molecular ion and cluster for stopping power in order to disclose the role of the vicinage effect on the Coulomb explosion and energy deposition of molecules and clusters in plasma. On the other hand, as a promising scheme for ICF, both a strong laser field and an intense ion beam are used to irradiate a plasma target. So the influence of a strong laser field on stopping power is significant. We discussed a large range of laser and plasma parameters on the coulomb explosion and stopping power for correlated-ion cluster and C60 cluster. Furthermore, in order to indicate the effects of different cluster types and sizes on the stopping power, a comparison is made for hydrogen and carbon clusters. In addition, the deflection of molecular axis for diatomic molecules during the Coulomb explosion is also given for the cases both in the presence of a laser field and laser free. Finally, a future experimental scheme is put forward to measure molecular ion stopping power in plasmas in Xi’an Jiaotong University of China.
Matter and Radiation at Extremes
- Publication Date: Jan. 01, 2018
- Vol. 3, Issue 2, 67 (2018)
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