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This Defense Intelligence Agency reference document, dated 10 March 2010, covers inertial electrostatic confinement (IEC) fusion. It was produced in FY 2009 under the DIA's Advanced Aerospace Weapon System Applications (AAWSA) program. The report focuses on work at the University of Illinois Urbana-Champaign and reviews IEC basics, experiments, theory and applications such as neutron sources, explosives detection and space propulsion. It concludes by proposing a breakeven experiment for p-11B fusion that uses a hydrogen plasma simulation.
“BEAMS”43 pages
UNCLASSIFIED/;SflHl 8FFIIItliL '1181!! 8HLV results. Rider was particularly interested in the claim that due to its beam-like non- Maxwellian plasma, the IEC can burn "advanced fusion fuels" such as D- 3 He and p- 11 B easier than traditional Maxwellian type plasma devices (Tokomaks, etc.). Thus, he considered use of D-T, D-D, D- 3 He, 3He-3 He, p- 11 B and p- 6Li fuels. Due to their high Z components, all of these fuels must battle large energy losses via Bremsstrahlung. These losses were evaluated using the traditional formula, but his evaluation has a built in bias since the loses depend heavily on the electron ion temperature ratio which in turn depends strongly on the values assumed as already discussed. Deviation from an equilibrium electron energy distribution also strongly affects radiation emission. Using the Maxwellian average values, he found that Bremsstrahlung losses would be prohibitively large for 3He- 3He, p- 11 B, and p- 6Li reactors and will be a considerable fraction of the fusion power for D- 3He and D-D reactors limiting use to D-T. As a corollary, he concludes in contradiction with earlier claims that it does not appear possible for the dense central region of a reactor-grade IEC device to maintain a significantly non-Maxwellian ion distribution or keep a low electron to ion temperature ratio. The problem, however, is that the assumed rate constants would naturally force this conclusion. Further, these rate constants lead to Rider's build-in result forcing the ions to form a Maxwellian distribution with a mean energy close to the energy of the potential. Consequently, in his analysis, ions in the energetic tail of the distribution are lost at rates faster the fusion rate, giving low Q values. Rider considered the Polywell type IEC and even with exceedingly optimistic assumptions about the potential well, he found the electron losses are intolerable for all fuels "except perhaps DT". Based on these results, Rider concludes that for the IEC system to be used as a fusion reactor it will be necessary to find methods to "circumvent these problems, especially the excessive Bremsstrahlung losses". Certainly reducing radiation losses should be an ongoing study, but his pessimism appears to be overdone. The problem with Rider's analysis is his not using reaction and scattering rates averaged over the non-Maxwellian distribution characteristic of an IEC reactor. This includes both the beam-like ion distribution and the large ion-electron temperature ratio. This very basic energy analysis should be redone with revised reaction rate data, but to date have not been reported. Despite questions about Rider's analysis and pessimistic conclusion, his recommendations of issues to study and overcome remain quite valid. NEUTRON SOURCE SIMULATIONS Several simulation studies have focused on neutron source type IECs. In this case, as opposed to future power reactors, the background gas is of sufficient pressure, resulting in beam-background scaling of the fusion rate (i.e., theoretically this gives a current x pressure scaling). Charge exchange also becomes a significant factor in device performance. In Reference 4.8, Miley et al. used an analytical model of charge- exchange collisions in the IEC plasma to include ion time-of-flight and fusion neutron generation rates. Results from the model simulating 10 mA of o+ ion current in a 30-cm diameter IEC device at 50 kV matched the experimental results of 106 fusion neutrons per second. The model was also used to find the effects of grid diameter on neutron yield and show that the yield scales as grid diameter is raised to the power -0.41. This factor is very close to the experimental scaling observed from the UIUC neutron source 44 UNCLASSIFIED,' }P8"1 8PPll!l"'I! l!l!il! 8111!¥
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Report, from the dia collection. The PDF is mirrored here; the original link is under it. 72 pages are in the text index: search them above, or from the library's search.