A new twist for inertial fusion energy: Impact ignition

A totally new ignition scheme is proposed, in which the compressed DT main fuel is ignited by impact collision of another fraction of separately imploded DT fuel, which is accelerated in the hollow conical target to hyper-velocities in the order of 108 cm/s. Its kinetic energy is directly converted into thermal energy corresponding to temperatures >5 keV on the collision with the main fuel, and this self-heated portion plays the role of ignitor. The ignitor shell is irradiated typically by nsec-pulses at intensities >1015 W/cm2 and laser wavelength of 0.35 μm to exert ablation pressures >100 Mbar. A preliminary two-dimensional hydrodynamic simulation shows substantial heating of the compressed core. The impact-shell acceleration and consequent working windows for the beam and target parameters are addressed based on a rocket model. Simple physics, high-energy coupling efficiency, low cost, not needing a PW laser, and affordability of investigation in laboratories under rather well-established physical understanding and experimental know-how are considered to be the notable advantages of the present scheme.