High-energy-density (HED) physics is the study of matter having a pressure above 0.1 Mbar (10 GPa) and containing free electrons not present in the solid state.It has emerged in recent decades as an active area of research, which also includes the use of experimental systems that produce such conditions. In this talk I will provide an introduction to HED physics. HED systems play host to a wide range of quantum mechanical, many-body, electromagnetic, and relativistic effects. HED experiments often use large lasers, although several other types of device can also access this regime. Because of its unique ability to create, in the laboratory, high pressure and high-temperature states, high-Mach number shock waves, and highly ionized matter, there are many connections between HED physics and astrophysics. After providing some history and context, I will highlight various recent work.
Studies of equations of state, relevant to the structure of planets, have revealed the biggest surprises in recent years, showing that dense matter regimes long thought to be simple in fact are not. Our research at Michigan in radiation hydrodynamics is now focused on radiative reverse shocks in colliding flows, relevant to open questions regarding the “hot spot” in cataclysmic-variable binary stars. We have recently produced the first laboratory radiative reverse shock. Our research in the dynamics of magnetized flows seeks to produce and study the impact of magnetization on jet impacts events like those in T-Tauri stars. We have produced a source plasma jet and are about to add magnetization. The resulting dynamics will be relevant to disk formation, jet production, and hydrodynamic and MHD turbulence. Our research in HED hydrodynamics is focused on the long-term evolution of hydrodynamic instabilities. We use our CRASH code to model these and other HED experiments from laser deposition through long-term radiation-hydrodynamic behavior.
