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AAWSAP DIRD, Inertial Electrostatic Confinement Fusion, March 2010

U.S. Department of War · 2010-03-10 · 72 pages · text from the file's own layer

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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beam-like ions. Since electron energy loss processes such as radiation emission are
serious, the Lawson temperature criterion must be modified for the IEC. A first rough
estimate is the Te/T1< 1/3 for DT. (Here T1and Te are the ion and electron
"temperatures", respectively). Control of th is ratio is a complex physics issue, involving
the relative ion and electron source rates and energies and the potential well structure.
In later sections use of p- 11B (hydrogen-boron-11) fuel in the IEC is considered. This is
very attractive since it provides all charged particle reaction products, making this an
unique "aneutronic" system. Such a reactor represents a truly ideal system from an
environmental and energy sustainability perspective. However, for such fuels, t he
Larson criterion becomes much more demanding, increasing nT by two orders of
magnitude and T to 150 kV. Also, for the IEC, a Te/T1< 1/9 becomes essential. (Using
temperature ration is a very simplified representation. The radiation losses are quite
sensitive to deviation in the actual energy distribution of the ions and electrons . For
example, electron Bremsstrahlung emission primarily comes from the high energy "tail"
of the electron distribution while energy transfer with ions is dominated by the "foot" of
the electron distribution. At high powers, interactions in these regions can become quite
non -linear, depleting or "burning out0 the local populations in these regions. This effect
causes energy losses to saturate, hence can be quite beneficial under some
circumstance . However, the phenomenon is complex to evaluate numerically, so little
has been reported on it for IECs to date). The very aggressive p- 11B Lawson
requirement is employed in the design of the breakeven experiment of Section VI.
While this discussion of IEC physics has been greatly simplified, it hopefully provides
more insight into the basic concepts and issue before delving into more detail.
IEC BACKGROUND
Inertial Electrostatic Confinement (IEC) was conceived of by Philo Farnsworth, the
inventor of electronic television, as an approach to fusion power using electrostatic
fields for confinement (Reference 1.2). When he did this in 1955, the prime approaches
being pursued worldwide were magnetic confinement or inertial (laser compression of
targets) confinement. In fact, electrostatic confinement had been written off by most
scientists due to Earnshaw's theorem (Reference 1.4) which stated that plasma could
not be confined by electrostatic fields alone. That was simply an expression of the fact
that use of a biased plate to confine one species, say ions, would automatically attract
the opposite species, electrons, such that the whole plasma would transport to the
plate. Farnsworth seemed to intuitively understand that this theorem assumed steady
state, so that if, as in IEC, the ions were dynamically moving and confined, they would
electrostatically confine the electrons. Farnsworth went further and realized that in a
spherical system virtual electrodes would form a high density plasma region if the
confined ions were focused at the center of the sphere (Reference 1.2).
While Hirsh worked with Farnsworth to demonstrate early experimental success with
IEC experiments (Reference 1.2), the concept passed from view as magnetic and
inertial confinement resea1rch exponentiated. Then in the late 1990s R. W. Bussard
revived the concept with the hybrid IEC magnetic approach (Reference 1.6- 1.7). In this
approach the electrons were confined in the magnetic field, forming a potentials trap for
ions. [Note the similarity to the original conceptual potential well discussed by Elmore,
et al. (Reference 1.1)]. Upon invitation by R.W. Bussard to join this effort, the author,
George Miley, undertook supporting experiments that were a variation of the original
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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.