Radiation properties of radiative shock in xenon

Abstract

<sec>Radiative shock is an important phenomenon both in astrophysics and in inertial confinement fusion. In this paper, the radiation properties of X-ray heated radiatve shock in xenon is studied with the simulation method. The radiative shock is described by a one-dimensional, multi-group radiation hydrodynamics model proposed by Zinn [Zinn J 1973 <i> J. Comput. Phys.</i> <b>13</b> 569]. To conduct computation, the opacity and equation-of-state data of xenon are calculated and put into the model. The reliabilities of the model and the physical parameters of xenon are verified by comparing the temperature and velocity of the radiative shock calculated by the model with those measured experimentally. </sec><sec>The evolution of the radiative shock involves abundant physical processes. The core of the xenon can be heated up to 100 eV, resulting in a thermal wave and forming an expanding high-temperature-core. Shortly, the hydrodynamic disturbances reach the thermal wave front, generating a shock. As the thermal wave slows down, the shock gradually exceeds the high-temperature-core, forming a double-step distribution in the temperature profile. </sec><sec>The time evolution of the effective temperature of the radiative shock shows two maximum values and one minimum value, and the radiation spectra often deviate from blackbody spectrum. By analyzing the radiation and absorption properties at different positions of the shock, it can be found that the optical property of the shock is highly dynamic and can generate the above-mentioned radiation characteristics. When the radiative shock is just formed, the radiation comes from the shock surface and the shock precursor has a significant absorption of the radiation. As the shock temperature falls during expansion, the shock precursor disappears and the radiation inside the shock can come out owing to absorption coefficient decreases. When the shock becomes transparent, the radiation surface reaches the outside edge of the high-temperature-core. Then, the temperature of the high-temperature-core decreases further, making this region also optically thin, and the radiation from the inner region can come out. Finally, the radiation strength falls because of temperature decreasing. </sec>