AAWSAP DIRD, Aneutronic Fusion Propulsion II, November 2010

This Defense Intelligence Reference Document, dated 1 November 2010, was prepared by the Defense Intelligence Agency's Defense Warning Office under the Advanced Aerospace Weapons System Applications program. It reviews fusion plasma physics, confinement methods and propulsion concepts that use aneutronic fusion fuels such as hydrogen and boron-11. It concludes that pulsed DPF or IEC thrusters may replace satellite ion thrusters in the near term. It also finds that aneutronic fusion propulsion will not be practical beyond the solar system without breakthrough propulsion physics.

From the source: Release of 2026-09-18 Incident: 11/1/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD revisits aneutronic fusion propulsion in a more systems-oriented manner, arguing that fusion concepts using low-neutron fuels such as proton-boron or helium-3 could become attractive for space propulsion because they reduce shielding burdens and may support direct conversion of charged-particle energy into thrust or onboard power. The report reviews the relevant fusion plasma physics and focuses on several candidate confinement approaches, then connects those concepts to possible applications in near-space, orbital, and interplanetary propulsion. It presents the most plausible nearer-term use as very high-power electric or plasma propulsion for satellites and deep-space missions rather than atmospheric flight or interstellar travel, while emphasizing that major obstacles remain in ignition, sustained confinement, system mass, power handling, fuel storage, launch integration, and end-to-end engineering.

UNCLASSIFIED/ Jfdk OFFICIAL U.!I! 9HL>f
Ion lqectOI' fl
llagllelE
... Pllsllla
Tlmtstl
\
Figure 9. Colliding Beam Fusion Reactor [Cheung et al. 2004]
Dense Plasma Focus Reactors
The Dense Plasma Focus (DPF) designs that operate at extremely high plasma pressure
because of the intense electrostatic pulse have been evaluated for (p,B 11)-fueled
propulsion systems. A parametric analysis by Knecht12 has shown that a system of 16
to 24 Mg can produce 400-900 MW of power with thrusts of 500-1000 kN at lsp of
1,500-2,000 seconds. More detailed analyses of this design indicate that for a 16-Mg
system using direct energy conversion coils at the thruster nozzle, (Figure 10)
producing an lsp of about 1300 seconds at 800 MW could generate about 1000 kN of
thrust.13
This system is continuously fueled with H2 and boron gas, and the electrodes are pulsed
at a 10-Hz rate or higher with the > 100 keV plasma fusion products and unfused fuel
expelled to provide thrust after passing through a direct-energy converter cooled by a
separate H2 coolant that is also expelled in the plasma stream.
Magneto- Inertial Confinement
Reactors
The concept of magnetized target fusion
using field-reversed configuration plasmoids
has been tested. 14 A high-density
compressed plasmoid is formed by a staged
axial and radial compression of two
colliding/merging FRC plasmas where the
energy that is required for the implosion
compression and heating of the magnetized
target plasmoid is stored in the kinetic
energy of the plasmas used to compress it.
The confinement properties are expected to
achieve ignition for aneutronic fuels and may
lead to the smaller reactor mass for
propulsion of 20 Mg producing
300 MW (shown in Figure 11).
Figure 10. DPF Thruster System
with Direct Conversion
UNCLASSIFIED//FOR OfifilCIA.k Wi& 0NLY
12