A consensus is emerging in the plasma physics and astrophysics communities that many opportunities exist for significant advances in understanding the physics of high energy density plasmas through an integrated approach to investigating the scientific issues in related subfields. Understanding the physics of high energy density plasmas will also lead to new applications and benefit other areas of science. Learning to control and manipulate these plasmas in the laboratory will benefit national programs, such as inertial confinement fusion and the stockpile stewardship program, through the development of new ideas and the training of a new generation of scientists and engineers. Furthermore, advanced technologies in the areas of high-speed instrumentation, optics (including x-ray optics), high-power lasers, advanced pulse power, and microfabrication techniques can be expected to lead to important spin-offs.
High energy density experiments span a wide range of areas of physics including plasma physics, laser and particle beam physics, materials science and condensed matter physics, nuclear physics, atomic and molecular physics, fluid dynamics and magnetohydrodynamics, intense radiation-matter interaction, and astrophysics. While a number of scientific areas are represented in high energy density physics, many high energy density research techniques have grown out of ongoing work in plasma science, astrophysics, beam physics, accelerator physics, magnetic fusion, inertial confinement fusion, and nuclear weapons research. The intellectual challenge of high energy density physics lies in the complexity and nonlinearity of the collective interaction processes that characterize all of these subfields of physics.
It should be emphasized that while high energy density physics is a rapidly developing area of research abroad, particularly in Europe and Japan, the primary focus of this report is on assessing the present capabilities and compelling research opportunities in the United States.
To illustrate the energy scale of the high energy density regime, some of the systems that deliver the energy in high energy density laboratory experiments in the United States can be considered. Typical state-of-the-art short-pulse lasers and the electron beams generated at the Stanford Linear Accelerator Center can be focused to deliver 1020 watts per square centimeter (W/cm2) on target. The present generation of lasers employed in inertial confinement fusion (on the NIKE facility at the Naval Research Laboratory, on OMEGA at the Laboratory for Laser Energetics at the University of Rochester, and at the TRIDENT laser laboratory at Los Alamos National Laboratory) deliver 1 to 40 kilojoules (kJ) to a few cubic millimeters volume in a few nanoseconds. In Z-pinch experiments on the Z-machine at Sandia National Laboratories, 1.8 megajoules (MJ) of soft x rays are delivered to a few cubic centimeters volume in about 5 to 15 nanoseconds (ns). With the planned upgrades of existing facilities and the completion of the National Ignition Facility (NIF) at the Lawrence