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.

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“The Times”31 pages

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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region is essential to decrease the center potential and consequently allow incoming
beam ions to penetrate into the core region. In the DaIEC, it is possible to assist this
effect by an external control of the centerline potential by applying a bias voltage to the
dipole coil. In the UIUC experiment this was done by applying a voltage to a small
copper ring inserted in the core of the dipole magnet. The increase in the electron
density with a small center line bias applied was about 30 percent while the applied
voltage to the dipole structure was ~3 percent of the discharge voltage. The present
setup prevented the use of larger applied voltages which could further improve
neutralization, but these results still demonstrate the basic concept of dipole focusing
with coil bias control.
Figure 3.6 shows how the electron density changes with increasing magnetic field
measured at various coil biases in the current experiment. It is found that electron
density increases about 17 times more than that of non-magnetic field measurement.
So far, this increase is very close to our theoretical estimations.
Electron density vs B-field 25mTorr
I.00E+0S
0 100 200 300 400 500 600 700 800
B-field strength (Gauss) I--- Ground -+- Vc=-lOOV ----r- Vc=+IOOV I
Figure 3.6. Electron Density vs. Dipole Magnet Field Strength at 25mTorr, 20mA
The next section turns to some very interesting diagnostic studies of IEC devices,
including a jet thruster configuration, done by Joe Khachan's group at the University of
Sydney, Australia.
KHACHAN'S STUDIES AT U OF SYDNEY
Joe Khachan's IEC research at the University of Sydney has stressed studies of optical
emission spectroscopy of gridded IEC devices (Reference 3.11, 3.12). Using Doppler
spectroscopy of the Hydrogen Ha line they have shown that the micro-channels in an
IEC discharge operating in the units at tens of mTorr pressure range (for voltages less
than 30 kV) are mostly composed of molecular ions with approximately 20 percent
atomic hydrogen. They have also developed a spectroscopic model based on collisional
radioactive modeling to spectroscopically measure ion densities, electron energies and
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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.