Shiva Nova; Laser Fusion Scientific Feasibility, TB 002 6-77
Livermore, CA: Lawrence Livermore Laboratory, 1977. Presumed First Edition, First printing. Wraps. 32 pages plus covers. Illustrations (some in color). The objective of Shiva Nova was to prove the scientific feasibility of laser fusion for civilian and military applications. Proof of feasibility would be achieved by demonstrating high-energy gain fusion micorexplosions. This key milestone required a laser systems of extremely high performance, capable of producing 200 to 300 terawatts of laser power. The Shiva laser was a powerful 20-beam infrared neodymium glass (silica glass) laser built at Lawrence Livermore National Laboratory in 1977 for the study of inertial confinement fusion (ICF) and long-scale-length laser-plasma interactions. Presumably, the device was named after the multi-armed form of the Hindu god Shiva, due to the laser's multi-beamed structure. Shiva was instrumental in demonstrating a particular problem in compressing targets with lasers, leading to a major new device being constructed to address these problems, the Nova laser. The basic idea of any ICF device is to rapidly heat the outer layers of a "target", normally a small plastic sphere containing a few milligrams of fusion fuel, typically a mix of deuterium and tritium. The heat burns the plastic into a plasma, which explodes off the surface. Due to Newton's Third Law, the remaining portion of the target is driven inwards, eventually collapsing into a small point of very high density. The rapid blowoff also creates a shock wave that travels towards the center of the compressed fuel. When it meets itself in the center of the fuel, the energy in the shock wave further heats and compresses the tiny volume around it. If the temperature and density of that small spot is raised high enough, fusion reactions will occur.
The fusion reactions release high-energy particles, which collide with the high density fuel around it and slow down. This heats the fuel further, and can potentially cause that fuel to undergo fusion as well. Given the right overall conditions of the compressed fuel – high enough density and temperature – this heating process can result in a chain reaction, burning outward from the center where the shock wave started the reaction. This is a condition known as "ignition", which can lead to a significant portion of the fuel in the target undergoing fusion, and the release of significant amounts of energy.
To date most ICF experiments have used lasers to heat the targets. Calculations show that the energy must be delivered quickly in order to compress the core before it disassembles, as well as creating a suitable shock wave. The laser beams must also be focussed evenly across the target's outer surface in order to collapse the fuel into a symmetric core. Although other "drivers" have been suggested, lasers are currently the only devices with the right combination of features.
Shiva was never expected to reach ignition conditions, and was primarily intended as a proof-of-concept system for a larger device that would. Even before Shiva was completed, the design of this successor, then known as Shiva/Nova, was well advanced. Shiva/Nova would emerge as Nova in 1984. Shiva was heavily instrumented, and its target chamber utilized high-resolution, high-speed optical and X-ray instruments for the characterization of the plasmas created during implosion. Many experiments including testing the "indirect mode" of compression using hohlraums were performed at Shiva until its dismantling in 1981. Shiva's target chamber would be reused on the Novette laser. In 1983, Novette became the first laser to be engineered with optical frequency converters made of potassium dihydrogen phosphate (KDP) crystals, which convert the infrared light to shorter ultraviolet wavelengths. The 2.5-kilojoule Novette was a test bed and interim target facility between Shiva and the 10-beam Nova. More than ten times more powerful than Shiva, Nova produced up to 150,000 joules of infrared and 40,000 joules of ultraviolet laser light in 2.5-nanosecond pulses, for up to 16 trillion watts of power. Nova produced the largest laser fusion yield to date in 1986—a record 11 trillion fusion neutrons. In 1987, Nova compressed a fusion fuel target to about one-thirtieth of its original diameter. The first Tron movie used the Nova laser for its location shots. Condition: Very good.
Keywords: Laser Fusion, Inertial Confinement, Shiva Nova, Neodymium Glass, Laser-Plasma Interactions, Target Compression, Fusion Ignition, Novette, Lawrence Livermore
[Book #80340]
Price: $65.00