Radiation flow through gold-doped hydrocarbon foam is investigated and a model is presented to calculate effective opacity for an inhomogeneous,pressure-equilibrated gold/foam mixture based on the Levermore–Pomraning...Radiation flow through gold-doped hydrocarbon foam is investigated and a model is presented to calculate effective opacity for an inhomogeneous,pressure-equilibrated gold/foam mixture based on the Levermore–Pomraning method for binary stochastic media.The effective opacity dependance on the size of the gold particles and the foam temperature are studied.The results suggest that when the mixture temperature is lower than 250 eV,the opacity difference between the 5μm particle mix case and the atomic mix case is large enough to induce a significant discrepancy in radiation transport,which is confirmed by the hydrodynamic simulation.展开更多
As a fundamental and crucial research topic in the direct-driven inertial confinement fusion（ICF）,especially for shock ignition（SI）,investigation on the laser coupling with planar lowZ targets is beneficial for de...As a fundamental and crucial research topic in the direct-driven inertial confinement fusion（ICF）,especially for shock ignition（SI）,investigation on the laser coupling with planar lowZ targets is beneficial for deep physical comprehension at the primary phase of SI.The production of the intense shock and the shock coalescence in the multi-layer targets,driven by the 3ω intense laser（351 nm the wavelength）,were studied in detail with the 1D and 2D radiation hydrodynamic simulations.It was inferred that the 1D simulation would overrate the shock velocity and the ablation pressure of the spike;the coalescence time and the velocity of the coalescence shock depended evidently on the pulse shape and the start time of the spike.The present study can also provide a semi-quantitative reference for the design of the SI decomposition experiments on the Shenguang-III prototype laser facility.展开更多
Hot dense titanium plasma was produced by irradiating a CH foam coated titanium layer with nanosecond laser pulses.The time-integrated emission spectra of He-like titanium were measured by using an absolutely calibrat...Hot dense titanium plasma was produced by irradiating a CH foam coated titanium layer with nanosecond laser pulses.The time-integrated emission spectra of He-like titanium were measured by using an absolutely calibrated flat crystal spectrometer.The synthetic spectra obtained by the steady collisional-radiative(CR)equilibrium model associated with the hydrodynamic simulations were compared with the experimental spectra.The results show that the electron density increases up to 5×10^(21) cm^(-3) with CH foam of density 40 mg/cc.This work indicates that an overlay of CH foam on a solid target is beneficial to create an optimum condition for K-shell emissions from a high density plasma region.展开更多
An experiment was performed on the Shenguang III prototype laser facility to continue the study on hohlraum radiation source with approximately constant radiation temperature using a continuously shaped laser pulse.A ...An experiment was performed on the Shenguang III prototype laser facility to continue the study on hohlraum radiation source with approximately constant radiation temperature using a continuously shaped laser pulse.A radiation source with a flattop temperature of about130 e V that lasted about 5 ns was obtained.The previous analytical iteration method based on power balance and self-similar solution of ablation was modified taking into account the plasma movements and it was used to design the laser pulse shape for experiment.A comparison between experimental results and simulation is presented and better agreement was achieved using the modified method.Further improvements are discussed.展开更多
文摘Radiation flow through gold-doped hydrocarbon foam is investigated and a model is presented to calculate effective opacity for an inhomogeneous,pressure-equilibrated gold/foam mixture based on the Levermore–Pomraning method for binary stochastic media.The effective opacity dependance on the size of the gold particles and the foam temperature are studied.The results suggest that when the mixture temperature is lower than 250 eV,the opacity difference between the 5μm particle mix case and the atomic mix case is large enough to induce a significant discrepancy in radiation transport,which is confirmed by the hydrodynamic simulation.
基金supported by the National High-Tech R&D Program(863 Program)of ChinaNational Natural Science Foundation of China(Nos.11205143,11505167)
文摘As a fundamental and crucial research topic in the direct-driven inertial confinement fusion（ICF）,especially for shock ignition（SI）,investigation on the laser coupling with planar lowZ targets is beneficial for deep physical comprehension at the primary phase of SI.The production of the intense shock and the shock coalescence in the multi-layer targets,driven by the 3ω intense laser（351 nm the wavelength）,were studied in detail with the 1D and 2D radiation hydrodynamic simulations.It was inferred that the 1D simulation would overrate the shock velocity and the ablation pressure of the spike;the coalescence time and the velocity of the coalescence shock depended evidently on the pulse shape and the start time of the spike.The present study can also provide a semi-quantitative reference for the design of the SI decomposition experiments on the Shenguang-III prototype laser facility.
基金Supported by the Foundation of China Academy of Engineering Physics under Grant No 2011A0102005the Foundation of Science and Technology on Plasma Physics Laboratory under Grant No 9140C680203110C6804.
文摘Hot dense titanium plasma was produced by irradiating a CH foam coated titanium layer with nanosecond laser pulses.The time-integrated emission spectra of He-like titanium were measured by using an absolutely calibrated flat crystal spectrometer.The synthetic spectra obtained by the steady collisional-radiative(CR)equilibrium model associated with the hydrodynamic simulations were compared with the experimental spectra.The results show that the electron density increases up to 5×10^(21) cm^(-3) with CH foam of density 40 mg/cc.This work indicates that an overlay of CH foam on a solid target is beneficial to create an optimum condition for K-shell emissions from a high density plasma region.
文摘An experiment was performed on the Shenguang III prototype laser facility to continue the study on hohlraum radiation source with approximately constant radiation temperature using a continuously shaped laser pulse.A radiation source with a flattop temperature of about130 e V that lasted about 5 ns was obtained.The previous analytical iteration method based on power balance and self-similar solution of ablation was modified taking into account the plasma movements and it was used to design the laser pulse shape for experiment.A comparison between experimental results and simulation is presented and better agreement was achieved using the modified method.Further improvements are discussed.
