Ion acceleration due to explosions of nanoparticles driven by hot electrons

Plasma expansion into vacuum and resultant ion acceleration is studied both analytically and numerically, where the expansion of an initially uniform nanoparticle with radius $R_{f0}$ and electron density $n_{e0}$ is driven by explosion of thrmal electrons with initial temperature $T_{e0}$. Such key outputs as the energy spectrum, maximum ion kinetic energy, and electrons-to-ions energy transfer efficiency 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 [Phys. Plasmas Vol.13, 012105 (2006)], which describes an expansion of a finite-size non-quasi-neutral plasma mass into vacuum with a full account of charge separation effects.