Radiation-temperature shock scaling of 1 ns laser-driven hohlraums

Abstract

Simulations of the x-ray ablation process of aluminum are performed using a one-dimensional multigroup radiation hydrodynamic code RDMG [F. Tinggui et al., Chin. J. Comput. Phys. 16, 199 (1999)]. The scaling relation of the peak temperatures of the x-ray sources with the shock velocities is studied, and its dependence on the temporal profile and the length of the x-ray sources is described and analyzed in this paper. A scaling relation applicable to x-ray sources of 1 ns pulse laser-driven hohlraums is proposed, the dependence of which is studied and found to be negligible. Our scaling relation of radiation temperature versus shock velocity is about 10 eV lower than that proposed by Kauffman et al. [Phys. Rev. Lett. 73, 2320 (1994)] for shock velocity of (4–8)×106 cm/s.

Sensitivity study of ignition capsule implosion performance on the hard x-ray spectral distribution of hohlraum

“…We note that although the uncertainties in EOS and opacity models may play a significant role on determining the exact HI amplitude and/or growing factor, the major conclusions of us on the impact of x-ray spectral distribution on implosion performance could not be altered with the use of different opacity or EOS models. The RDMG code has been well tested by the many ablation and implosion experimental results, 26,27 and that confirms the reliability of RDMG in the simulation research of ignition capsule implosion.…”

A novel method for determining the M-band fraction in laser-driven gold hohlraums

“…The thermodynamic quantities are derived either from the ideal gas model or from data of realistic equation of state. As introduced in our previous paper, 15 simulation results from RDMG were compared with that from LASNEX and experimental results. The good agreement confirmed the high reliability of RDMG in shock wave simulation study.…”

“…12,15 However, for a hot hohlraum, the M-band emission from wall material cannot be ignored and the radiation inside the hohlraum may obviously deviate from the Planckian distribution. 7,11 Besides, as shown in Fig.…”

“…Our opacity of Al has been checked in Ref. 15, while that of Ti is to be checked in our future experiments. According to our simulations, it leads to 1% error in shock wave velocity for Al and 1.3% for Ti if there was an error of 10% in opacity.…”

“…As well known, the shock wave technique is widely used to determine the peak radiation temperature T r inside a hohlraum. [12][13][14][15] By measuring the shock wave velocity V s in a witness plate mounted on the hohlraum wall, as shown in Fig. 1, the peak radiation temperature T r can be determined via a scaling relation of T r with V s .…”