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.
UNCLASSIFIED/ /FOR 8FFIEJIAL ~SE er•tv experimental parameters were obtained. The parameters which were varied include the background pressure, the ratio of electron to ion circulating currents, the applied potential difference between the grids, and the inner grid variables such as measured current, transparency, and construction error. When estimates of each of these parameters which simulate the ion injection mode experiment were inserted into the model, the resulting potential profile exhibited no more than a shallow potential well. This result is consistent with that of beam defection measurements in the ion injection mode experiments. In spite of these assumptions, the model is extremely valuable in determining the relative (sensitivity of the potential well profile and depth to effects of many of the system parameters. It has been found that for the "medium" level of ion currents under discussion, the most critical factors which inhibit deep well formation are inadequate spherical focusing and charge neutralization. The focusing is determined to a great extent by the degree to which the grids are spherical potential surfaces. The grid must approach a spherical shape within a few percent before other factors such as grid transparency and background pressure play an important role. However, as the current is increased, the requirements for sphericity are somewhat relaxed. For a grid construction error of less than 5 percent, increasing the grid transparency and decreasing the pressure will also lead to significant improvement in well depth." These results were somewhat encouraging. However, they showed that grid deformation could be very harmful. This deserves several comments. First, the present author (G. Miley) later showed that design of grids with larger openings provided the STAR mode where ion beams passed through the center of the openings, avoid ing grid collisions and making sphericity of the grid itself less important. This is important for small neutron/proton source type devices . However, the assumption of grids fails to address the question of how a grid could survive in a power reactor or if they could be eliminated to use a potent ial well with virtual electrode formation. The use of grids cannot be completely ruled out for power reactors. Magnetic field protection techniques, active cooling, etc. are conceivable. Another question relates to the role of background gas in the IEC. The point is this: When Miley moved to simplify the device for small neutron sources, he used the discharge between the grid and vessel to form the ions needed for acceleration and fusion. This inherently forces use of a modest background neutral gas pressure of the fuel (typically deuterium) inside the reaction vessel. That in turn results in ion reactions with the background gas becoming a dominant process in these IECs . Such interaction includes fusion itself, scattering, charge exchange, etc. This greatly changes the plasma physics of the IEC as opposed to the ideal of a potential well with "zero" background pressure. Some key differences in the physics of such IECs were brought out by Tim Thomson in his experimental study described in Reference 1.4. He noted that: "In present gridded systems, convergence is not important since beam -target fusion reaction dominate the reactivity of these devices, as evidenced by the linear scaling of reactivity of these devices, as evidenced by the linear scaling of reactivity with the cathode current. In fact, convergence may reduce the reactivity by forming a virtual anode that limits the centr al ion density. However, this space charge effect can be overcome by proper introduction of electrons. Good convergence is required to achieve optimal beam -beam reactivity scaling for the application that require higher fusion reaction rates, and the importance of symmetry in determining convergence places a UNCLASSIFIED/ /P"Olt 8FFIEJIAk Wliii QrslL¥ 7
Not linked to a story yet.
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.