Documents / Official release
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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was obtained from recirculation beam-beam reactions in a potential well such as in
Figure 2.1 (but without multiple structures). Indeed, to further confirm the existence of
a potential well, Hirsch did both collimated neutron and gamma measures. As shown in
the paper, he found structure for both consistent with well formation. One possible
explanation is that the ion-electron densities obtained were high enough to "burn out"
(completely ioni ze) the background neutrals in the potential well. There is no direct
evidence to support this view however.
These important results have never been fully explained. Attempts to reproduce his
experiments were done by Gardner and co-workers at Brigham Young University
(Reference 2.1) who borrowed the original device used by Hirsch. However, despite
many months of effort, the neutron production they obtained was significantly lower
than that reported by Hirsch. They attributed this problem to a failure to regain the gun
alignment necessary to have a highly converged plasma "core" in the center of the
device. A major hurdle to this appears to have been that no provision was made to
allow precision alignment of the gun ions entering the device (although the
investigators did not mention this explicitly). Later when Miley reinitiated gun
experiments, his first gun design followed many of the design elements used by Hirsch,
but incorporated electrostatic beam steering. This worked well, but the design was
eve ntually discarded to move to RF guns with much higher beam currents. In addition,
the gun desig n of Figure 1.5 uses a magnetic nozzle for reducing the exiting beam
diameter and to allow strong differential pumping (not used in the prior Hirsch
experiments).
It should be stressed again here that the terms "injector" and "gun" are misleading.
The objective is to simply "flow" low energy ions into the device such that they are then
accelerated to fusion energies by either the grid or the virtual electrode structure. Thus,
a loss of "excess" energy after injection is needed trap the ion, i.e. prevent it from
simply passing through the potential well and hitting the opposite wall. A biased
reflector on the opposite wall can be introduced to help prevent this, but this only works
well if the entering ions have little excess energy. To further understand this problem,
the reader is advised to study the design of the Hirsch chamber of Reference 2.2 which
uses an auxiliary biased grid ("reflector") near the wall. Indeed the issue of how to best
introduce ions into t he potential well so t hat t heir energy fa lls below that required to
escape the well is a key for proper design of the IEC. In addition to designs to cause an
initial ion energy loss to "drop" them into the potential well, designs with ion sourced
" imbedded" in t he well such that ions are born trapped are discussed later.
Gridded devices for near-term applications such as neutron activation analysis (NAA) do
not rely on virtual well potential traps. Rather, the negative bias of the grid forms a
potential trap, and ions are born within the potential trap by ionization collisions in the
internal plasma discharge.
Note that the electron injected case faces the same problem of getting ions into the
potential trap. The approach used with the Polywell employs an embedded ion source
plus relies on "burn out" densities to eliminate neutrals. Success with this technique,
after many problems, was the key that lead to the "breakthrough" reported by R. W.
Bussard (as noted earlier) just before he passed away.
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 72 pages are in the text index: search them above, or from the library's search.