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Defense Intelligence Reference Document Inertial Electrostatic Confinement Fusion

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This Defense Intelligence Agency reference document, dated 10 March 2010, covers inertial electrostatic confinement (IEC) fusion. It was produced in FY 2009 under the DIA's Advanced Aerospace Weapon System Applications (AAWSA) program. The report focuses on work at the University of Illinois Urbana-Champaign and reviews IEC basics, experiments, theory and applications such as neutron sources, explosives detection and space propulsion. It concludes by proposing a breakeven experiment for p-11B fusion that uses a hydrogen plasma simulation.

  • p. 8 …This is important for long run times since 10n bombardment of the grids, hence grid wire…
  • p. 9 …This time can be restated in terms of the number of ion recirculations in the IEC…
  • p. 15 …This work and others on the small gridded systems at that time showed several important problems…
  • p. 17 …interesting concept is the idea of ion focusing, either in space or time, or some other…
  • p. 18 …confinement time for aneutronic fusion. This assumes, however, very precise control is maintained over the energy…
  • p. 23 …By selecting the pulse width to match or exceed the ion confinement time, typically order of…
  • p. 27 …This is the approach used at the UIUC. However, introduction of the source into the configuration…
  • p. 30 …The second jet would serve the integration purpose of the platform without having to expend time…
  • p. 35 …The issue then is how to achieve adequate confinement times. The approach being pursued at UIUC…
  • p. 36 …step in a timely fashion, however. The Dipole Assisted IEC (DaIEC) The dipole assisted IEC DaIEC…
  • p. 38 …in the current experiment. It is found that electron density increases about 17 times more than…
  • p. 41 …Namely, the time scale for collisional degradation of the beam-like ion distribution function is crucial…
  • p. 42 …would homogenize the speed within the ion beam a~er some time, making the speed difference…
  • p. 43 …1) The electrostatic well is deep enough (Eo > 100 kV); 2) Ion confinement time is long…
  • p. 44 …The source to sink issue noted several times here can be explained as follows. Two opposite…
  • p. 49 …The time convergence test suggests that employing the largest time step compatible with accuracy in a…
  • p. 50 …When an ion beam is hot, the waves excited by the instability are ion acoustic type…
  • p. 51 …used an analytical model of charge- exchange collisions in the IEC plasma to include ion time…
  • p. 53 …Nevins, Can inertial electrostatic confinement work beyond the ion-ion collisional time scale?" Phys. Plasmas, Vol…
  • p. 54 …This method uses a pulsed high-energy neutron source and the time-of-flight (TOF) diagnostics…
  • p. 57 …The longer the charge time, the higher the charge in the energy storage capacitor bank and…
  • p. 58 …The challenge in these systems is that the unloading time is short and the container is…
  • p. 59 …by the number of detectors, the detector configuration, the collimated beam size, the acquisition time, and…
  • p. 62 …The Tokamak has a shorter trip time by employing a power level that is six times…
  • p. 63 …In this fashion, an array of multiple IECs increase the overall confinement time roughly in proportion…
  • p. 64 …This recirculation significantly increases the confinement time verses that of a simple cusp devise, leading to…
  • p. 65 …This re-trapping greatly increases the confinement time of a MCSA fusion device. 58 UNCLASSIFIED/;CEiOAt…
  • p. 66 …in the IEC high power-to-weight of the MCSA enables fast trip times. The concept…
  • p. 67 …across the outer surface, so increased confinement times have been achieved by going to the massively…
  • p. 68 …Here n is the ion density and Tis the ion confinement time. Assuming the converged core…
  • p. 69 …A specially designed radio frequency (RF) ion gun is installed on the side of the chamber…
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predict fusion rates. This latter achievement makes spectroscopic measurements
simpler to carry out since hydrogen can be used to predict these fusion rates, which
excludes the radiation hazard in a laboratory situation where shielding is not possible.
In follow-on work, they simplified the modeling of charge exchange with an analytical
approach to charge exchange modeling based on Markov chain theory.
Table 4.1. Comparison of Analytical and Numerical Estimates of Q-values in
a beam-Dominated Solution -- for a SO-kV Square Well.
Analytical BAFP
(Chacon)
With co-moving ions Q ~ 0.21 - Ref. 4.1, Nevins -
Without co-moving ions Q ~ 1.3 - Ref. 4.2, Chacon Q~ 1
The movement of neutrals moving away from the cathode seen from the spectroscopic
measurements was also confirmed by carrying out a dusty plasma measurement to
show charged micron sized insulating spheres (dust) experience a force away from the
cathode centre (Reference 3.13). The explanation of this was attributed to a local
potential maximum established at the center of the cathode, which accelerates ions at
that point away from the center. Due to charge exchange, ions become neutrals and
are able to leave along the microchannels out to the anode. The ion drag force on the
dust moved the dust particles away from the center. Based on this observation,
Khachan has engineered the collimated beam of exiting neutrals from the cathode to
make a simple electric propulsion thruster where a unidirectional micro-channel
emerges from a conical cathode (Reference 3.14). He claims that the specific impulse of
the thruster and its efficiency greatly exceed existing electric propulsion thrusters. Note
that this concept, while having some similarities, differs in some details from Miley's jet
thrusts describe earlier.
CONCLUDING REMARKS
The primary focus of this section has been on two key alternate geometries: The
cylindrical and jet IECs. Both provide unique capabilities for applications using IEC
sources and IEC space thruster, respectively. These uses, however, require competition
in commercial markets with other options. This IEC technology is just now emerging, so
its success in commercialization has yet to be established. More about such applications
is discussed in Section V.
In conclusion, the DaIEC is a very interesting alternate IEC configuration. However, it
has received little experimental study to date, so much more needs to be done to fully
evaluate its potential.
REFERENCES
3.1 B. Bromley, L. Chacon, and G. Miley, "Approximate Modeling of Cylindrical Inertial
Electrostatic Confinement, (IEC) Fusion Neutron Generator," Proc. 16th International
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Report, from the dia collection. The PDF is mirrored here; the original link is under it. 72 pages are in the text index: search them above, or from the library's search.