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This Defense Intelligence Agency reference document, dated 1 November 2010, is one of a series of advanced technology reports produced in FY 2010 under the Advanced Aerospace Weapons System Applications (AAWSA) Program. It covers fusion plasma physics, confinement methods, and propulsion concepts that use aneutronic fuels such as hydrogen and boron-11. It concludes that such thrusters may soon replace satellite ion thrusters. It also finds that they will not be practical beyond the solar system without breakthrough propulsion physics.
UNCLASSIFIED/)'P9R: 9PPll!ltllt '11815 8Htlf MAGNETO-INERTIAL CONFINEMENT This method of confinement is an adaptation of the inertial confinement system (ICF) described above, but also uses some of the methods developed for magnetic confinement in an attempt to lower the fusion ignition requirements for implosion velocity and power density. 9 This concept uses a strong magnetic field within a conducting shell (a magnetic flux conserver). The inertial fusion target plasma lies within the conducting shell. As the shell is imploded, the magnetic intensity increases dramatically, constraining and heating the plasma and facilitating fusion. This concept is being pursued in the United States by the Office of Fusion Energy Sciences of the Department of Energy. Currently there are two classes: High-gain magneto-inertial fusion (MIF) and low-to-intermediate-gain magneto-inertial fusion. High-Gain MIF The heating power directed into a hot spot for fusion ignition must be greater than the rate of heat energy loss, and this implies that a high implosion velocity is needed for high-yield fusion. However, a higher implosion velocity actually lowers the efficiency of fusion, since less of the cold fuel is assembled (the higher velocity increases the breakdown of density barriers or growth rate of the Rayleigh-Taylor instability). As described above, lasers are typically used for direct implosion of the fuel pellet but, to date, this is not very efficient and the cost per unit energy is high. With a magnetized target, however, the implosion velocity need not be so high to initiate fusion ignition, thus lowering the input energy cost without sacrificing efficiency. Low-to-Intermediate MIF For low-yield fusion, electromagnetic pulsed power can be substituted for lasers or particle beams to compress the target. A lower implosion velocity implies that a larger shell can be used, leading to longer burn duration and a much lower density target. It is thought that by using an imposed magnetic field, a solid or liquid shell (liner) and a gaseous target can be used, rather than the usual cryogenic solid fuel pellets. Such is the case for the Magnetized Target Fusion experiment being performed at LANL (shown in Figure 6). A similar pulsed compression of a fusion fuel gas can be achieved without a target by instead using Dense Plasma Focus (DPF) having annular electrodes (shown in Figure 7). In this case a capacitor bank is discharged into the electrodes driving a nanosecond to microsecond pulse that will heat the plasma created to ignition temperatures. This by far is the simplest and least elaborate magnetic confinement concept to achieve aneutronic fusion ignition. 9 UNCLASSIFIED/ ,'1"9i.! 91"1"!e!llit tl!9I!! 9HLV
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 36 pages are in the text index: search them above, or from the library's search.