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Defense Intelligence Reference Document Inertial Electrostatic Confinement Fusion

Defense Intelligence Agency · 72 pages · text from the file's own layer

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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In this RF gun, a graded index magnetic field is used to increase the ionization
efficiency. A key component is the magnetic focusing lens at the extraction port. This
allows very efficient differential pumping between the high pressure gun chamber and
the low pressure IEC chamber. It also provides some control of the angular velocity of
entering ions.
The UIUC RF ion-injector is shown attached to an IEC chamber in Figure 1.6, and a
photograph of the focal spot achieved with injection from this single injector is shown in
Figure 1.7. Note that ion scattering off of the center dense plasma "core" causes
noticeable (but "faint") recirculating ion beams observed in the photograph of the
discharge. With additional injectors, the recirculation pattern should become quite
symmetrical about the center. These studies did include differential pumping so that
number of recirculating passes, ~, by an ion was very low, roughly 2. The injected ion
current, I, was about SO mA. Still, based on measurements of neutrons emitted using
deuterium fuel, the Q (fusion energy gain/energy in) was remarkable for such a small
device, order of 10-6 . Based on these results, an aggressive p- 11 B breakeven
experiment using this type of IEC is discussed in Section VI.
Figure 1.6. RF Gun Attached to an IEC Chamber in
the UIUC Laboratory
CLOSING REMARKS
Figure 1.7. Photo of Center Spot Formation. The
main beam observed is a direct path along the injector
angle. Other faint light channels indicate beams for
scattering of the central core region.
As seen, a wealth of information has been developed in studies of gridded IEC devices.
However, the beam-background fusion used in these devices involves important
differences in physics compared to what is needed for future beam-beam IEC reactors.
Most notable is the need to maintain an extremely low background pressure to prevent
interactions with background neutrals. Further, physical grids are subject to damage at
high power levels. As pointed out, some studies show grids can survive at modest
powers. But, for aggressive power units such as the p- 11 B plant of Section VI, they
must be replaced with virtual electrode surfaces creating a deep potential well for ion
confinement. Upscattering out of the well must be minimized while electron
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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.