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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. 5 …Sketch of Two Opposite Limits of the Beam·Maxwellian Equilibrium .. 38 Figure 4.5. The Definition…
  • p. 6 …Comparison of Analytical and Numerical Estimates of Q-Values in a Beam-Dominated Solution -- for a…
  • p. 8 …shows the "Star Mode" discharge where ion beams are created that pass through the grid openings…
  • p. 9 …discussed later where the recirculating ions possess beam-like trajectories passing through the center of the…
  • p. 10 UNCLASSIFIED/ ;raA 8FFIIItliL ~81!! SHL'f beam-like ions. Since electron energy loss processes such as…
  • p. 11 …In addition, its beam-like reactions (highly non-Maxwellian) make the IEC very well suited for…
  • p. 13 …a beam created at the anode and accelerated by the applied cathode voltage; a low-energy…
  • p. 14 …Good convergence is required to achieve optimal beam-beam reactivity scaling for the application that require…
  • p. 15 …The observed loss of convergence with decreasing pressure and increasing current makes achieving significant beam-beam…
  • p. 16 …For a power reactor the objective is to obtain ion beam-beam collisions in this central…
  • p. 17 …the "conventional" beam-like one. A key issue for this concept is how much plasma compression…
  • p. 19 …The main beam observed is a direct path along the injector angle. Other faint light channels…
  • p. 21 …Note that six ion "guns" were used to create a low energy ion beam that entered…
  • p. 22 UNCLASSIFIED/;SflHl 8FFIIItliL ~81!! 8HL'I' was obtained from recirculation beam-beam reactions in a potential…
  • p. 23 …The key physics point is that the beam-beam fusion rate scales as the ion current…
  • p. 26 …Scoping calculations of beam-background fusion rates predict that a 3 He- 3 He reaction product…
  • p. 27 …of the ion density squared scaling for beam-beam reactions. REFERENCES 2.1 R. L. Hirsch…
  • p. 28 …As such, the beam convergence (compression) is limited to lower values, hence lower core densities (an…
  • p. 30 …by the intersection of the multiple ion beams, serves to deflect ions into the escaping jet…
  • p. 31 …The result is the formation of the intense space charge neutralized ion beam (or "plasma jet…
  • p. 32 …in the symmetric microchannels into a directed beam or jet. Comparison to a Conventional "Plasma" Thruster…
  • p. 33 …The ion beams finally exit through an opening in the ground sphere of the IEC device…
  • p. 35 …These devices operate with ~ 80- keV D-ion beams using the non-Maxwellian character of the…
  • p. 36 …Two ion sources inject 40-keV deuterium and helium-3 ion beams toward the center of…
  • p. 37 …Indeed in this case fusion is dominated by beam-beam (non- Maxwellian reactions). Also, the dipole…
  • p. 38 …the center potential and consequently allow incoming beam ions to penetrate into the core region. In…
  • p. 39 …Comparison of Analytical and Numerical Estimates of Q-values in a beam-Dominated Solution -- for a…
  • p. 40 …Hora, "Converging Beam Neutron Source for Driving a Sub-critical Fission Reactor", Proceedings, ICONE 8, CD…
  • p. 41 …Namely, the time scale for collisional degradation of the beam-like ion distribution function is crucial…
  • p. 42 …For example, a tightly focused monoenergetic ion beam is in fact a pessimistic scenario, because different…
  • p. 44 …Thus, weak sinks and strong sources will result in a large beam population, increasing the beam…
  • p. 45 …Sketch of Two Opposite Limits of the Beam-Maxwellian Equilibrium. The solid line corresponds to a…
  • p. 46 …injected beam current, average injection energy, energy spread associated with the velocity component in both parallel…
  • p. 47 …As stated in Section I, the current scaling for beam-beam reactions is strictly 12. However…
  • p. 48 …is very encouraging for formation of deep wells in IEC devices designed for reactors using beam…
  • p. 49 …To do this, it is assumed that the electrostatic confinement equilibrium ion beams are proportional to…
  • p. 50 …When an ion beam is hot, the waves excited by the instability are ion acoustic type…
  • p. 51 …Rider was particularly interested in the claim that due to its beam-like non- Maxwellian plasma…
  • p. 52 …Diagram Showing Equipotential Surfaces of the IEC Cathode Grid and Their Focusing Effect on a Beam…
  • p. 59 …of detectors, the detector configuration, the collimated beam size, the acquisition time, and other scan-related…
  • p. 63 …Alternately, for space propulsion, the proton beam, augmented by injection of heavy atoms to increase the…
  • p. 68 …Due to its inherent non-Maxwellian (beam-like) plasma, the IEC is especially well suited for…
  • p. 70 …This configuration is highly non-Maxwellian due to the beam dominated nature of the trapped ions…
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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
34
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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.