Fast ignition driven by quasi-monoenergetic ions: Optimal ion type and reduction of ignition energies with an ion beam array

摘要

Fast ignition of inertial fusion targets driven by quasi-monoenergetic ionbeams is investigated by means of numerical simulations. Light and intermediateions such as lithium, carbon, aluminium and vanadium have been considered.Simulations show that the minimum ignition energies of an ideal configurationof compressed Deuterium-Tritium are almost independent on the ion atomicnumber. However, they are obtained for increasing ion energies, which scale,approximately, as Z^2, where Z is the ion atomic number. Assuming that the ionbeam can be focused into 10 {\mu}m spots, a new irradiation scheme is proposedto reduce the ignition energies. The combination of intermediate Z ions, suchas 5.5 GeV vanadium, and the new irradiation scheme allows a reduction of thenumber of ions required for ignition by, roughly, three orders of magnitudewhen compared with the standard proton fast ignition scheme.