|perkins_iccaustin.pdf||2006-03-08 14:40:53||John Perkins|
The Status of Advanced Target Concepts for ICF and IFE
Author: John Perkins
Submitted: 2005-12-27 21:45:23
Co-authors: Max Tabak, Riccado Betti, Stephen Obenschain
PO Box 808 (L-018)
Livermore, CA 94551
The National Ignition Facility (NIF) via the multi-institutional National Ignition Campaign is poised in the 2010-2012 timeframe to demonstrate fusion ignition and gain in the laboratory for the first time. This landmark event will likely result in renewed interest in fusion and in its potential as a clean energy alternative to carbon-based fuels. However, although we have made significant progress in the science of inertial confinement fusion, our present reactor concepts have some way to go to be deemed fully competitive in the energy marketplace of the 21st century. In IFE, the target design dictates the driver requirements and chamber geometry. Consequently, the biggest leverage in reducing the size, cost and complexity of the reactor embodiment lies in the potential of advanced targets. In particular, advances in target design and performance are desirable in order to: (a) permit the testing of ICF target concepts at lower drive energies, (b) enable the design and construction of smaller, lower cost fusion engineering test facilities and (c) realize attractive, economically-competitive commercial reactors.
Accordingly, in this paper we review the prospects and potential performance of several advanced ICF target concepts, including:
* Fast ignition targets
* Higher velocity variants of conventional hotspot targets
* Shock-ignited targets
* Two-sided-drive targets
The objectives of such designs are to significantly reduce the driver energy for a given gain over that for conventional direct or indirect-drive targets while, in some concepts, relaxing the stringent symmetry and stability requirements that attend hotspot-ignited targets. In addition, asymmetric targets with two-sided drive might obviate the need for 4-Pi illumination geometry, thereby allowing the use of thick liquid walls. (The latter may be essential to ameliorate the material damage problems that pertain with solid, dry wall chambers). Finally, sufficiently high-gain target designs might enable the burning of advanced fusion fuels – D-D or D-3He – with their potential for advanced energy conversion of the mainly charged particle output.