  We study transverse and longitudinal electron heating effects on the target
stability and the ion spectra in the radiation pressure dominated regime of ion
acceleration by means of multi dimensional particle-in-cell (PIC) simulations.
Efficient ion acceleration occurs when the longitudinal electron temperature is
kept as low as possible. However, tailoring of the transverse electron
temperature is required in view of suppressing the transverse instability,
which can keep the target structure intact for longer duration during the
acceleration stage. We suggest using the surface erosion of the target to
increase the transverse temperature, which improves both the final peak energy
and the spectral quality of the ions in comparison with a normal flat target.
