Historical research guide · 0076 · 2010
DIRD Aneutronic Fusion Propulsion II
DIA / AAWSAP contractor
In one minute
The Defense Intelligence Agency’s 2010 report compares fusion propulsion schemes, on fuels such as hydrogen–boron-11 whose products are charged particles rather than tritium-breeding neutron streams. Charged fusion products could be directed through magnetic nozzles; the report contrasts them with the shielding and materials-replacement demands of deuterium-tritium reactions. It surveys field-reversed configurations, dense plasma focus and inertial electrostatic confinement. Its dense-plasma-focus design point is a 16-tonne system pulsed at 10 hertz or more, about 800 megawatts, about 1,000 kilonewtons and 1,300 seconds of specific impulse. Figures describe an electrostatic jet. These are design calculations, not flight results. The company list is a 2010 snapshot. The roadmap starts with physics and technology demonstrations and ends with a crewed mission; the report says fusion alone is not a practical interstellar system.
Connection
The report ties fuel choice to nozzle design, radiation shielding, power delivery and the path from a confinement experiment to a vehicle. It also separates a solar-system propulsion roadmap from the further physics needed for an interstellar trip.
From the source
The threshold for applying fusion to propulsion is considerably relaxed compared with terrestrial power, especially with fuels that avoid tritium: tritium must be continuously bred, and its reactions yield fast neutrons that require shielding and cause structural materials to be periodically replaced.Summary, p. v; Chapter 1: Concept Overview, pp. 1-2
Aneutronic ignition costs more to reach: the ignition temperature is up to a factor of ten higher than for deuterium-tritium, and the confinement power required for ignition is one to two orders of magnitude greater, which is why unique confinement concepts are needed rather than the tokamak.Chapter 2: Fusion Plasma Physics, Tables 2 and 3, pp. 4-5
A 16-tonne dense plasma focus system with direct energy conversion coils at the thruster nozzle, continuously fuelled with hydrogen and boron gas and pulsed at 10 Hz or higher, is analysed as producing about 800 MW and roughly 1,000 kN of thrust at a specific impulse of about 1,300 seconds, expelling plasma fusion products above 100 keV.Chapter 3: Fusion Propulsion, Dense Plasma Focus Reactors, p. 12
An inertial electrostatic confinement jet thruster is estimated to give 35 mN of thrust for 750 watts at 500 volts — a specific impulse of 3,000 seconds, or 45 mN per kilowatt, superior to advanced Hall current thrusters — and adding a 150 kWe ion beam to heat a proton–boron-11 plasma close to ignition would raise the specific impulse above 5,000 seconds with thrust above 5 N per kilowatt.Chapter 4: Applications, Earth Orbit, pp. 17-18
Five privately funded companies were already building the relevant reactors when the report was written — Lawrenceville Plasma Physics (dense plasma focus, proton–boron-11), TriAlpha (beam-heated field-reversed configuration, proton–boron-11), EMC2 (Polywell electrodeless inertial electrostatic confinement), Electron Power Systems and General Fusion — holding between 4 and 50 million dollars each, and their success in the next few years may accelerate the implementation of aneutronic fusion propulsion.Chapter 5: Recent Developments, Privately Funded Programs and Table 4, pp. 23-24
Aneutronic fusion propulsion will not be practical beyond the solar system unless breakthrough propulsion physics is developed that can assist the flight to the next stellar system, where fusion thrusters can then be used; the report’s roadmap runs physics demonstration, technology development, ground demonstration, flight demonstration and crewed mission across roughly 2010 to 2060.Chapter 6, Figure 20 roadmap, p. 29; Chapter 7: Conclusions, p. 30
The way in
https://documents2.theblackvault.com/documents/dia/AAWSAP-DIRDs/DIRD_37-DIRD_Aneutronic_Fusion_Propulsion_II.pdfHow to cite it
DIA / AAWSAP contractor (2010) DIRD Aneutronic Fusion Propulsion II https://documents2.theblackvault.com/documents/dia/AAWSAP-DIRDs/DIRD_37-DIRD_Aneutronic_Fusion_Propulsion_II.pdf