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This Defense Intelligence Reference Document, dated 10 March 2010, was prepared by the Defense Intelligence Agency's Defense Warning Office under the Advanced Aerospace Weapon System Applications Program. It surveys the basics, experimental status, theory and possible uses of inertial electrostatic confinement (IEC) fusion, with emphasis on work at the University of Illinois Urbana-Champaign. It covers neutron sources, explosives detection and space propulsion. It ends by proposing a 12-gun hydrogen plasma experiment meant to show breakeven conditions for p-11B fuel.
From the source:Release of 2026-09-18 Incident: 3/10/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys inertial electrostatic confinement (IEC) fusion, a relatively unconventional fusion concept that uses electric fields rather than the more established magnetic or laser-based approaches to confine ions, and it reviews both the underlying physics and the experimental work associated with the concept. The report emphasizes that IEC may have nearer-term value as a compact neutron, proton, or x-ray source and as a platform for studying experimental fusion approaches, while also presenting more ambitious possibilities such as aneutronic power generation and propulsion applications. At the same time, it makes clear that the concept remained far from practical fusion power, with experimental devices operating several orders of magnitude below breakeven and with major unresolved issues involving confinement, losses, grid damage, and scale-up. Overall, the document treats IEC as a technically interesting but still highly speculative path toward fusion energy, while suggesting that its more limited spin-off applications were more plausible in the near term than its long-range power generation or propulsion applications.
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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- 3He and p- 11 B
easier than traditiona l Maxwellian type plasma devices {Tokomaks, etc.). Thus, he
considered use of D-T, D-D, D- 3He, 3He- 3He, p- 11B 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 form ula, 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
proh ibitively large for 3He- 3He, p- 11B, 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 D+ ion current in a 30-cm
diameter IEC device at SO 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
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