  The proton-Boron 11 (p-B11) fusion reaction is much harder to harness for
commercial power than the easiest fusion reaction, namely the deuterium and
tritium (DT) reaction. The p-B11 reaction requires much higher temperatures,
and, even at those higher temperatures, the cross section is much smaller.
However, as opposed to tritium, the reactants are both abundant and
non-radioactive. It is also an aneutronic reaction, thus avoiding
radioactivity-inducing neutrons. Economical fusion can only result, however, if
the plasma is nearly ignited; in other words if the fusion power is at least
nearly equal to the power lost due to radiation and thermal conduction. Because
the required temperatures are so high, ignition is thought barely possible for
p-B11, with fusion power exceeding the bremsstrahlung power by only around 3\%.
We show that there is a high upside to changing the natural flow of power in
the reactor, putting more power into protons, and less into the electrons. This
redirection can be done using waves, which tap the alpha particle power and
redirect it into protons through alpha channeling. Using a simple power balance
model, we show that such channeling could reduce the required energy
confinement time for ignition by a factor of 2.6 when energy is channeled into
thermal protons, and a factor of 6.9 when channeled into fast protons near the
peak of the reactivity. Thus, alpha channeling could dramatically improve the
feasibility of economical p-B11 fusion energy.
