  There currently exists a number of different schemes for laser based ion
acceleration in the literature. Some of these schemes are also partly
overlapping, making a clear distinction between the schemes difficult in
certain parameter regimes. Here, we provide a systematic numerical comparison
between the following schemes and their analytical models: light-sail
acceleration, Coulomb explosions, hole boring acceleration, and target normal
sheath acceleration (TNSA). We study realistic laser parameters and various
different target designs, each optimized for one of the acceleration schemes,
respectively. As a means of comparing the schemes, we compute the ion current
density generated at different laser powers, using two-dimensional
particle-in-cell (PIC) simulations, and benchmark the particular analytical
models for the corresponding schemes against the numerical results. Finally, we
discuss the consequences for attaining high fluxes through the studied laser
ion-acceleration schemes.
