Multi-layer phenomena in petawatt laser-driven acceleration of heavy ions

Abstract Laser-accelerated high-flux-intensity heavy-ion beams are of importance for new-type accelerators. A particle-in-cell program (Smilei) is employed to simulate the entire process of SEL-100 PW laser-accelerated heavy particles using different nanoscale short targets with thickness of 100 nm Cr, Fe, Ag, Ta, Au, Pb, Th, and U, as well as thickness of 200 nm Al and Ca. An obvious stratification is observed in the simulation. The layering phenomenon is a hybrid acceleration mechanism reflecting Target Normal Sheath Acceleration and Radiation Pressure Acceleration, and this phenomenon is understood from the simulated energy spectrum, ionization, and spatial electric field distribution. According to the stratification, it is suggested that high quality of heavy-ion beams could be expected for fusion reactions to synthesize superheavy nuclei. Two plasma clusters in the stratification are observed simultaneously, which suggest new techniques for plasma experiments, as well as thinner metal targets in precision machining process.