Studies of ultra-intense laser plasma interactions for fast ignition

Copyright 2000 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 7(5), 2014-2022, 2000 and may be found at http://dx.doi.org/10.1063/1.87402

Basic and integrated studies for fast ignition

The process of fast ignition (FI) using various laser systems was analyzed. A Petta watt (PW) laser system was used to study the basic elements relevant to FI, which could also be injected to a compressed core. Using a spherical target inserted with a Au cone guide for the PW laser pulse, an imploded core was heated upto 1 keV resulting in neutron increase which is 1000 times more than that without heating pulse

Fast heating of ultrahigh-density plasma as a step towards laser fusion ignition

Modern high-power lasers can generate extreme states of matter that are relevant to astrophysics, equation-of-state studies and fusion energy research. Laser-driven implosions of spherical polymer shells have, for example, achieved an increase in density of 1,000 times relative to the solid state. These densities are large enough to enable controlled fusion, but to achieve energy gain a small volume of compressed fuel (known as the 'spark') must be heated to temperatures of about 108 K (corresponding to thermal energies in excess of 10 keV). In the conventional approach to controlled fusion, the spark is both produced and heated by accurately timed shock waves, but this process requires both precise implosion symmetry and a very large drive energy. In principle, these requirements can be significantly relaxed by performing the compression and fast heating separately; however, this 'fast ignitor' approach also suffers drawbacks, such as propagation losses and deflection of the ultra-intense laser pulse by the plasma surrounding the compressed fuel. Here we employ a new compression geometry that eliminates these problems; we combine production of compressed matter in a laser-driven implosion with picosecond-fast heating by a laser pulse timed to coincide with the peak compression. Our approach therefore permits efficient compression and heating to be carried out simultaneously, providing a route to efficient fusion energy production