Laser Ion Acceleration: Status and Perspectives for Fusion

High power short-pulse lasers presently reach peak powers of a few hundred Terawatts up to a Petawatt, and routinely reach focal intensities of 10(18) - 10(21) W/cm(2). These lasers are able to produce various secondary radiation, from relativistic electrons and multi-MeV/nucleon ions to high-energetic X-rays and gamma-rays. In many laboratories world-wide large efforts are presently devoted to a rapid development of this novel tool of particle acceleration, targeting nuclear, fundamental and high-field physics studies as well as various applications. Based on the Radiation Pressure Acceleration mechanism, laser-accelerated ion beams can be generated with solid-state density, thus exceeding beams from conventional accelerators by about 14 orders of magnitudes. This opens the perspective of a novel reaction scheme called 'fission-fusion', where in a first step fission is induced both in laser-accelerated fissile projectiles from a 'production target' and in a second 'reaction target' again from fissile material hit by the accelerated projectiles. Due to the unprecedented ion density, (neutron-rich) light fission fragments from projectile and target can fuse again, forming extremely exotic species approaching the region of the N = 126 waiting point of the r-process. Within the next 5 years a new EU-funded large-scale research infrastructure (ELI: Extreme Light Infrastructure) will be constructed, with one of its four pillars exclusively devoted to nuclear physics based on high intensity lasers (ELI-Nuclear Physics, to be built in Magurele/Bucharest). Studies of laser-induced nuclear reactions like the 'fission-fusion' mechanism will be amongst the experimental flagship projects pursued there.