The behaviours of ionization and shock propagation in radiatively heated material is crucial for the understanding of indirect drive inertial confinement fusion as well as some astrophysics phenomena. In this work, ra...The behaviours of ionization and shock propagation in radiatively heated material is crucial for the understanding of indirect drive inertial confinement fusion as well as some astrophysics phenomena. In this work, radiation field with a peak temperature of up to 155 eV was generated in a gold cavity heated by four laser beams on the SG-II laser system and was used to irradiate a plastic foam cylinder at one end. The radiatively ablated foam cylinder was then backlighted side-on by x-ray from a laser-irradiated Ti disk. By observing the transmission decrease due to the shock compression of the foam cylinder, the trajectories of shock front were measured, and from the onset of the intense thermal emission from the side of the cylinder, the propagations of the ionization front were also observed on the same shot. The experimental measurements were compared to predictions of the radiation hydrodynamics code Multi-1D and reasonable agreements were found.展开更多
The propagation of a supersonic heat-wave through copper-doped foam with a density of 50 mg/cm^3 was experimentally investigated. The wave is driven by 140 eV Holhraum radiations generated in a cylindrical gold cavity...The propagation of a supersonic heat-wave through copper-doped foam with a density of 50 mg/cm^3 was experimentally investigated. The wave is driven by 140 eV Holhraum radiations generated in a cylindrical gold cavity heated by a 2 kJ, ins laser pulse （0.35 μm）. The delayed breakout time of the radiation waves from the rear side of the foam is measured by a three-chromatic streaked x-ray spectrometer （TCS） consisting of a set of three-imaging pinholes and an array of three transmission gratings coupled with an x-ray streak camera （XSC）. With one shot, simultaneous measurements of the delays of the drive source and the radiation with two different energies （210 eV, 840 eV） through the foam have been made for the first time. The experimental results indicate that the time delays vary with photon energies. The radiation with an energy of 210 eV propagates at a lower velocity. The radiating heat wave propagates with a velocity that is larger than the sound speed. Using TGS, the transmitting spectrum was measured, and then lower limit of the optical depth which is more than 1, was obtained. The experimental data were in agreement with numerical simulations.展开更多
基金supported by the Science and Technology Fund of the China Academy of Engineering Physics (Grant No. 2007B08003)
文摘The behaviours of ionization and shock propagation in radiatively heated material is crucial for the understanding of indirect drive inertial confinement fusion as well as some astrophysics phenomena. In this work, radiation field with a peak temperature of up to 155 eV was generated in a gold cavity heated by four laser beams on the SG-II laser system and was used to irradiate a plastic foam cylinder at one end. The radiatively ablated foam cylinder was then backlighted side-on by x-ray from a laser-irradiated Ti disk. By observing the transmission decrease due to the shock compression of the foam cylinder, the trajectories of shock front were measured, and from the onset of the intense thermal emission from the side of the cylinder, the propagations of the ionization front were also observed on the same shot. The experimental measurements were compared to predictions of the radiation hydrodynamics code Multi-1D and reasonable agreements were found.
基金The project supported by National High Technique Development Project (863) No.2002AA843130Scientific Fund of CAEP No. 20030214
文摘The propagation of a supersonic heat-wave through copper-doped foam with a density of 50 mg/cm^3 was experimentally investigated. The wave is driven by 140 eV Holhraum radiations generated in a cylindrical gold cavity heated by a 2 kJ, ins laser pulse （0.35 μm）. The delayed breakout time of the radiation waves from the rear side of the foam is measured by a three-chromatic streaked x-ray spectrometer （TCS） consisting of a set of three-imaging pinholes and an array of three transmission gratings coupled with an x-ray streak camera （XSC）. With one shot, simultaneous measurements of the delays of the drive source and the radiation with two different energies （210 eV, 840 eV） through the foam have been made for the first time. The experimental results indicate that the time delays vary with photon energies. The radiation with an energy of 210 eV propagates at a lower velocity. The radiating heat wave propagates with a velocity that is larger than the sound speed. Using TGS, the transmitting spectrum was measured, and then lower limit of the optical depth which is more than 1, was obtained. The experimental data were in agreement with numerical simulations.
