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This Defense Intelligence Reference Document, dated 1 November 2010, was produced by the Defense Intelligence Agency under its Advanced Aerospace Weapon System Applications (AAWSA) Program. It surveys propulsion technologies that include chemical, ion, and nuclear fission rockets, fusion schemes, aneutronic fusion, and antimatter propulsion. It also covers radiation shielding and speculates on research needs over the next 30 years for missions from low Earth orbit to Mars, Jupiter, Saturn, and Alpha Centauri. The document concludes that aneutronic fusion promises to be an important mechanism for future space propulsion.
UNCLASSIFIED/ /PS"-. 9PPl!ltllt t!l91!! 9HLY Chapter 2: Nuclear Fusion Rocket Design CLASSIC NUCLEAR FUSION SCHEMES Nuclear fusion, which powers the Sun and the stars, begins with the collision of two lightweight atomic nuclei to create two new particles with the release of energy. As an example, if two specific isotopes of hydrogen (tritium and deuterium) were to collide, the reaction would produce a neutron plus an alpha particle (ionized helium nucleus). (2.1) The 17.6 MeV of energy is split between the kinetic energy of the neutron (14.1 MeV) and the helium nucleus (3.5 MeV) based on conservation of energy and conservation of momentum. The kinetic energy is eventually converted into heat in a fusion reactor. The 14.1-MeV neutron will penetrate far into lead or steel shielding and can cause considerable material damage. The ionized helium nucleus, however, will not go very far through any material without being absorbed and dissipating its energy as heat. There is a novel way to capture the energy from the ionized nucleus. As shown in Error! Reference source not found., a magnetohydrodynamic (MHD) generator can b e used to harness the energy from the helium ions and convert it directly into electricity. The electricity could be used to power an ion drive on a spacecraft or provide power for life support. Equation 2.2, known as the Lorentz force equation, illustrates which parameters are involved and how they are related: Direction of the Magnetic Field, B Pathof1on.s B~tween the Magnets w w .I! F~e(Vxff) Electodes on the Top and Bottom of the Channel Carry Electrical Current Away on Each Side of the Channel Generate the Magnetic Field Figure 5. Schematic Design of a Magnetohydrodyanamic (MHD) Generator. (2.2) The velocity (V) of the ions interacts with the magnetic field (B) and forces positively charged ions to move downward in the channel to an electrode where they impart an 13 UNCLASSIFIED/ ,'1"81l 81"1"U!l*le lel!ii lil'lle~I
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 50 pages are in the text index: search them above, or from the library's search.