“BEAMS”43 pages
- 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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This capability can provide valuable data regarding 3He fusion cross sections at "low"
energies with better counting statistics than accelerator measurements. It appears that
good progress has been made in this direction.
CLOSING COMMENTS
The experiments selected for this section are far from exhaustive. The main
concentration here is on ion-injected IECs such as studied at the UIUC, although
various electron injected devices such as the "Polywell" are mentioned. The
experiments were selected then to explain some issues and status relative to gridded
devices for near-term applications such as neutron sources and also to address some
issues such as ion injection related to future fusion power units. The latter issues
revolve around how to create deep potential wells in the IEC and trap the reacting ions
in the well while excluding neutral gas atoms. The use of external ion sources with
differential pumping then becomes a key approach for production of ions while keeping
ultra low background pressure in the reacting chamber. This is the approach used at
the UIUC. However, introduction of the source into the configuration such that the ions
are born at potentials below the well depth is another possibility as shown by the hybrid
magnetron source work in Japan. Another point noted is the advantage of using pulsed
operation to obtain high peak ion currents to take advantage of the ion density squared
scaling for beam-beam reactions.
REFERENCES
2.1 R. L. Hirsch, "Inertial-Electrostatic Confinement of Ionized Fusion Gases," J. Appl.
Physics 38, no.11, (1967) pp. 4522-4534.
2.2 A. L. Gardner, "Studies of Charged-Particle Distributions in an Electrostatic
Confinement System, "U. S. Atomic Energy Commission Final Report N. C00-2180-7,
Washington, D. C. (1974).
2.3 G. H. Miley, Y. Gu, J. M. DeMorea, R. A. Stubbers, T. A. Hochberg, J. H. Nadler,
and R. A. Anderl, "Discharge Characteristics of the Spherical Inertial Electrostatic
Confinement (IEC) Device," IEEE Transactions Plasma Science, Vol. 24, No. 4, (1997)
pp. 733-739.
2.4 T.J. McGuire and R.J. Sedwick, "Improving IEC Particle Confinement Times Using
Multiple Grids" 7th US-Japan IEC Workshop, Los Alamos National Laboratory, NM,
March 14-16 (2005).
2.5 R.A. Anderl, J.K. Hartwell, J.H. Nadler, J.M. DeMora, R.A. Stubbers, and G.H.
Miley, "Development of an IEC Neutron Source for NDE," 16th Symposium on Fusion
Engineering, eds. G.H. Miley and C.M. Elliott, IEEE Conf. Proc. 95CH35852, IEEE,
Piscataway, NJ, (1996) pp. 1482-1485.
2.6 Y. Gu, M. Williams, R. Stubbers, and G. Miley, "Pulsed Operation of Spherical
Inertial-Electrostatic Confinement Device", Fusion Technology, Vol. 30, no. 3, (1996)
pp. 1342-1346.
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