Ion acceleration due to explosions of nanoparticles driven by thermal electrons

Plasma expansion into vacuum and resultant ion acceleration is theoretically studied, where the expansion of an initially uniform nanoparticle with radius R_f0 and electron density n_e0 is driven by explosion of thermal electrons with initial temperature T_e0. Such key outputs as the energy spectrum and maximum ion kinetic energy are explicitly given as a function of R_f0, n_e0, and T_e0. The simulation results turn out to be well reproduced by a self-similar solution, which describes non-relativistic expansion of a finite plasma mass with a full account of charge separation effects.