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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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primarily because the explicit time-step
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when they cannot resolve the fastest
time scale supported by the model.
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finite-grid instabilities that require ~
resolution of spatial scales comparable Figure 4.10. Plot of Growth Rate of Spherically
Converging/Diverging Ion-Beam Instability for the
to the Debye length. In order to Variation of the Angular Velocity Spread, i.e., for 13 =
improve the conservations property of T/ lecticl (Nomenclature defined in Reference 6.1}
implicit moment particle-in-cell
algorithm, H.J. Kim developed a fully implicit particle- in-cell scheme and implemented it
using a Jacobian-free Newton-Krylov algorithm that does not require actual formation
and storage of the Jacobian matrix to minimize the computational costs. The scheme
features the following properties: 1) fully implicit method where all quantities of both
the particle and the field equations are consistent at each time step, and 2) a good
property for energy conservations.
H. J. Kim's study verified that the algorithm correctly handles the typical electrostatic
modes. For example, the results agree with the linear dispersion relations for simple
limits of two cold electron counter-streaming instabilities, electron Landau damping,
and ion acoustic waves. The simulation experience presented here demonstrates the
energy conservation property of the systems and the efficacy of nonlinear solver
combined with an efficient pre-condition ing wh ich is derived from the nonlinear Poisson
equation and particle description relations. For ion acoustic waves, the maximum
variation in the total energy is much less than 0.1 percent, indicating that a fully
implicit technique performs well in that particular simulation. The number of linear and
nonlinear iterations is significantly reduced when the preconditioner is applied. In fact,
for the case of linear iterations, the iteration number of a preconditioned linear system
is 10 times smaller than that of a linear solver without preconditioner. In addition, grid
convergence test shows that the scaling of CPU time is virtually linear according to the
grid number. The time convergence test suggests that employing the largest time step
compatible with accuracy in a given calculation is the most efficient route for obtaining
the solution because the CPU time decreases as the t ime step increases.
H. J. Kim performed a normal mode analysis of the ion-ion counter-streaming instability
in a spherical inertial electrostatic confinement in order to gain insights into the ion
injected inertial electrostatic confinement equilib rium configuration. To do this, it is
assumed that the electrostatic confinement equilibrium ion beams are proportional to
1/r2, effectively neutralizing the background electron density. It is evident from the
analysis of cold ion beams that two-stream instability in finite spherical systems may be
excited for small beam velocities compared to those of homogeneous and infinite
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