AAWSAP DIRD, Aneutronic Fusion Propulsion I, November 2010

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are 800 keV and 300 keV, respectively, much higher than the 50 keV required for D-T
neutronic fusion.
/H
0
m /He
~
0 /
ffi
/He
/1B @ /
~
m /He
3x /He+8.7MeV
Figure 10. The Fusion of Hydrogen-1 and Boron-11 Produces Three Alpha Particles
Fortunately, both lithium-6 and boron-11 are readily available, while tritium must be
manufactured due to its 12.6-year halflife. Lithium-6 represents 7.5% of all lithium on
Earth. Lithium is mined at Silverpeak, Nevada.
Another concern in choosing an effective aneutronic fusion scheme is bremmstrahlung,
or "braking radiation." This term refers to the x-rays emitted as electrons pass through
metals and interact with electrons in the outer shells of the metal atoms. In order to
ignite a fusion reaction, the gases must be heated to the point where they ionize and
form a plasma. Electrons stripped from the ions in the plasma will interact with the
walls of the chamber that house the plasma and bremmstrahlung x-rays will result.
Bremmstrahlung is a parasitic process that decreases the temperature of the plasma
and reduces the chance of fusion. While the two favored fusion schemes, p-Li6 and p­
B11, can generate significant bremmstrahlung losses, there are techniques proposed
using electromagnets to direct both electrons and ions to minimize x-ray production.
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