A new approach to inertial fusion

Projectile fusion is a new approach to inertial fusion that is simpler, more energy efficient, and has lower physics risk. Inertial fusion is a pulsed process, where, like an internal combustion engine, a small amount of fuel is injected and sparked to make it burn. The main existing approach to inertial fusion uses a large laser as the "spark plug", triggering the reaction. We use a high velocity projectile instead.

The projectile impacts a target containing fusion fuel. The target must focus the energy of the projectile, imploding the fuel to the temperatures and densities needed to make it fuse.

The target design is the key technology

Projectile fusion has been considered before and the required velocity was found to be very high. First Light’s target technology is the crucial game-changer. Our targets have two aspects, an amplifier and a fuel capsule. The amplifier does two things, it boosts the pressure generated by the impact of the projectile, delivering a much higher pressure to the fuel. This amplification reduces the required projectile velocity; the fuel implodes much faster than the original impact.

The amplifier also creates convergence. Whilst the initial impact comes from only one side, the fuel is squashed from many directions. This is crucial for reaching the required final density.

In a power plant the target would simply be dropped into the reaction chamber and the projectile would be launched downwards though the same entrance, such that it catches up with the target at the right moment. The simple geometry of the vessel, with only one entrance hole, allows the use of a liquid first wall. The flowing liquid protects the chamber from the huge energy release, neatly sidestepping some of the most difficult engineering issues in other approaches to fusion.