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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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3.13 J. Khachan, A. Samarian, "Dust diagnostics on an inertial electrostatic
confinement discharge", Phys. Letters A, vol. 363, no. 4 (2007) pp. 297-301.
3.14 L. Blackhall, J. Khachan, "A simple electric thruster based on ion charge
exchange", vol. 40, No. 8, (2007) pp. 2491-2494.
Section IV. IEC Theory
Early basic IEC theory was briefly
described in Section I. Section IV will
now turn to some more recent studies
starting with an early study by Bill
Nevins (Reference 4.1) that has caused
concern in the community about the
suitability of the IEC for a fusion power
reactor. Nevins did a semi analytic
analysis where IEC systems are
predicated including a non-equilibrium
ion distribution function. Coulomb
collisions between ions cause this
distribution to relax to a Maxwellian on
the ion-ion collisional time scale. His
Onion-shaped
conductor
ov
Reflector
'''
/,,'0'
1/.;,~;;
"~
e emitter
\\\analysis suggests that the input power
required to prevent this relaxation, thus
maintaining the IEC configuration for
times beyond the ion-ion collisional time -Wo kV - few V
Superconducting
magnet
scale, is greater than the fusion power
produced. Thus, he concluded that IEC
systems show little promise for the
development of commercial electric
power plants. Nevin's analysis appears
to be very thorough, however, as
discussed next, it suffers from several
Figure 4.1. Cross Section of the Experimental Layout
of the PFX-1 Experiment. The emitter -electron source,
onion-shaped anode and reflector form an axial
electrostatic well for electron axial confinement. Radial
confinement is provided by the axial magnetic field. The
reflector is biased slightly more negative than the emitter
to avoid electron losses to the reflector.
key, but subtle assumptions that may force the pessimistic results.
Later, to further explore issues raised by Nevins, Luis Chacon, doing his thesis with G.
Miley, decided to use a Fokker Plank model for analysis of the IEC so that some of the
questionable assumptions used by Nevins could be relaxed. This study, presented in
Reference 4.2, specifically dealt with a Penning-type IEC due to interest in the Penning
trap experiment at LANL. The experimental device, PFX-1 is illustrated in Figure 4.2
while the reactor-like configuration modeled by Chacon is shown in Figure 4.2. It should
be stressed however, that the conclusions still apply in principle to the ion injected IEC
since the issues involve the potential well trapping common to both. The Penning trap
and the ion injected devices differ in how the well is formed and stabilized, but the
physics of trapped plasma confinement is the same. Namely, the time scale for
collisional degradation of the beam-like ion distribution function is crucial since short
times (as the fusion time) would prevent a power reactor. Nevins addressed this issue
by calculating collisional relaxation rates from a beam-like, monoenergetic ion
population, absolutely confined in a square potential well. From his analysis, Nevins
concluded that the IEC will thermalize and lose ion focusing before enough fusion
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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.