Abstract Details

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pb_parks-1.pdf2006-02-22 07:39:25Paul Parks

Plasma Liners Formed by the Merging of Supersonic Plasma Jets

Author: Paul B. Parks
Submitted: 2005-12-15 16:04:59

Co-authors: Y.C. Francis Thio

Contact Info:
General Atomics
PO Box 85608
San Diego, California   92186-5
USA

Abstract Text:
A new magnetized-target inertial fusion energy (MTIFE) concept proposed by F. Thio may solve the problem of the lack of adequate standoff distance between the driver and the site of explosive energy release. This has been a longstanding concern with most MTIFE concepts. The idea uses a spherically symmetric plasma liner to adiabatically compress and heat a magnetized plasmoid to fusion ignition conditions. The imploding liner is created by the intersection of multiple ~70 plasma jets launched from the periphery of the blast chamber with high velocity ~100 km/s, and high number density ~10^{20} cm^{-3}. For DT jets with ratio of specific heats gamma = 5/3, the jets need to be highly supersonic, with a Mach number M_{jet} > 50 in order to obtain a ~10,000 fold amplification of the liner shell density and momentum-flux-density near the compressed target plasma. In general, the Mach number required to inertially contain an MTF target at a pressure p_0 depends strongly on the ratio of specific heats of the liner gamma, p_0 = rho_{jet} u_{jet}^2 M_[jet}^{2/(gamma-1)} Lambda(gamma) where Lambda(gamma) = [(gamma - 1)(gamma+1)]^{gamma)gamma-1)} {1/gamma+[1+gamma+square root{17+gamma(2+gamma)}]/4}. Hence, liners with lower specific heats are favored simply because lower M_{jet} may be used. Strongly radiating jets/liners, which have lower effective gamma, may therefore be advantageous. Future work will examine the fusion energy gain of this concept. If economically attractive gains of ~10 can be attained, the fusion energy yield will be ~1-2 GJ, which is easily containable, in contrast to the prohibitively large 100 GJ yields expected for the conventional MTIFE approach. The production of highly supersonic plasma jets on the larger scale might also open a new window into the physics of high Mach number astrophysical jets.

This work was supported by the U.S. Department of Energy under Grant De-FG03-95ER54309.

Y.C. Francis Thio affiliation: NASA Marshall Space Flight Center currently with DOE Office of Fusion Energy Sciences, USA.

Characterization: C

Comments:

The University of Texas at Austin

Innovative Confinement Concepts Workshop
February 13-16, 2006
Austin, Texas

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